ConstantFolding.cpp revision debcb01b0f0a15f568ca69e8f288fade4bfc7297
1bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell//===-- ConstantFolding.cpp - Analyze constant folding possibilities ------===// 2bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell// 3bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell// The LLVM Compiler Infrastructure 4bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell// 54ee451de366474b9c228b4e5fa573795a715216dChris Lattner// This file is distributed under the University of Illinois Open Source 64ee451de366474b9c228b4e5fa573795a715216dChris Lattner// License. See LICENSE.TXT for details. 7bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell// 8bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell//===----------------------------------------------------------------------===// 9bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell// 10bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell// This family of functions determines the possibility of performing constant 11bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell// folding. 12bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell// 13bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell//===----------------------------------------------------------------------===// 14bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell 15bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell#include "llvm/Analysis/ConstantFolding.h" 16bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell#include "llvm/Constants.h" 17bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell#include "llvm/DerivedTypes.h" 185520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner#include "llvm/Function.h" 199a38e3e3991ea443e555d8060f91202a786acdd4Dan Gohman#include "llvm/GlobalVariable.h" 20bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell#include "llvm/Instructions.h" 21bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell#include "llvm/Intrinsics.h" 22508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson#include "llvm/LLVMContext.h" 235520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner#include "llvm/ADT/SmallVector.h" 24c5f6a1f9d61d74017d90e149728cb3d283e0a0e0Chris Lattner#include "llvm/ADT/StringMap.h" 2503dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner#include "llvm/Target/TargetData.h" 26c25e7581b9b8088910da31702d4ca21c4734c6d7Torok Edwin#include "llvm/Support/ErrorHandling.h" 27bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell#include "llvm/Support/GetElementPtrTypeIterator.h" 28bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell#include "llvm/Support/MathExtras.h" 29bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell#include <cerrno> 3097af751deb9b26fd42fbcee082da9ccc4ded5b45Jeff Cohen#include <cmath> 31bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswellusing namespace llvm; 32bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell 3303dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner//===----------------------------------------------------------------------===// 3403dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner// Constant Folding internal helper functions 3503dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner//===----------------------------------------------------------------------===// 3603dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner 3703dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner/// IsConstantOffsetFromGlobal - If this constant is actually a constant offset 3803dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner/// from a global, return the global and the constant. Because of 3903dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner/// constantexprs, this function is recursive. 4003dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattnerstatic bool IsConstantOffsetFromGlobal(Constant *C, GlobalValue *&GV, 4103dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner int64_t &Offset, const TargetData &TD) { 4203dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner // Trivial case, constant is the global. 4303dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner if ((GV = dyn_cast<GlobalValue>(C))) { 4403dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner Offset = 0; 4503dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner return true; 4603dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner } 4703dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner 4803dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner // Otherwise, if this isn't a constant expr, bail out. 4903dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner ConstantExpr *CE = dyn_cast<ConstantExpr>(C); 5003dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner if (!CE) return false; 5103dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner 5203dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner // Look through ptr->int and ptr->ptr casts. 5303dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner if (CE->getOpcode() == Instruction::PtrToInt || 5403dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner CE->getOpcode() == Instruction::BitCast) 5503dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner return IsConstantOffsetFromGlobal(CE->getOperand(0), GV, Offset, TD); 5603dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner 5703dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner // i32* getelementptr ([5 x i32]* @a, i32 0, i32 5) 5803dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner if (CE->getOpcode() == Instruction::GetElementPtr) { 5903dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner // Cannot compute this if the element type of the pointer is missing size 6003dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner // info. 61f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner if (!cast<PointerType>(CE->getOperand(0)->getType()) 62f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner ->getElementType()->isSized()) 6303dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner return false; 6403dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner 6503dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner // If the base isn't a global+constant, we aren't either. 6603dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner if (!IsConstantOffsetFromGlobal(CE->getOperand(0), GV, Offset, TD)) 6703dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner return false; 6803dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner 6903dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner // Otherwise, add any offset that our operands provide. 7003dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner gep_type_iterator GTI = gep_type_begin(CE); 71de2d74b213844b17eb5327fba27f21e699d3af66Gabor Greif for (User::const_op_iterator i = CE->op_begin() + 1, e = CE->op_end(); 72785c6af9797fcf551feef70f2ecb5cd075b6e3c4Gabor Greif i != e; ++i, ++GTI) { 73de2d74b213844b17eb5327fba27f21e699d3af66Gabor Greif ConstantInt *CI = dyn_cast<ConstantInt>(*i); 7403dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner if (!CI) return false; // Index isn't a simple constant? 7503dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner if (CI->getZExtValue() == 0) continue; // Not adding anything. 7603dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner 7703dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner if (const StructType *ST = dyn_cast<StructType>(*GTI)) { 7803dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner // N = N + Offset 79b1919e2f08ecb37140af676fd2916f8d5ed7df3dChris Lattner Offset += TD.getStructLayout(ST)->getElementOffset(CI->getZExtValue()); 8003dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner } else { 81ca5183d445954a9b2a570d6bbba1bc2b00ad6442Jeff Cohen const SequentialType *SQT = cast<SequentialType>(*GTI); 82777d2306b36816a53bc1ae1244c0dc7d998ae691Duncan Sands Offset += TD.getTypeAllocSize(SQT->getElementType())*CI->getSExtValue(); 8303dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner } 8403dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner } 8503dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner return true; 8603dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner } 8703dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner 8803dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner return false; 8903dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner} 9003dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner 9103dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner 9203dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner/// SymbolicallyEvaluateBinop - One of Op0/Op1 is a constant expression. 9367e3566d8f6875e9c92d224f493023408a66227eNick Lewycky/// Attempt to symbolically evaluate the result of a binary operator merging 9403dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner/// these together. If target data info is available, it is provided as TD, 9503dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner/// otherwise TD is null. 9603dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattnerstatic Constant *SymbolicallyEvaluateBinop(unsigned Opc, Constant *Op0, 97508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson Constant *Op1, const TargetData *TD, 98e922c0201916e0b980ab3cfe91e1413e68d55647Owen Anderson LLVMContext &Context){ 9903dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner // SROA 10003dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner 10103dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner // Fold (and 0xffffffff00000000, (shl x, 32)) -> shl. 10203dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner // Fold (lshr (or X, Y), 32) -> (lshr [X/Y], 32) if one doesn't contribute 10303dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner // bits. 10403dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner 10503dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner 10603dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner // If the constant expr is something like &A[123] - &A[4].f, fold this into a 10703dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner // constant. This happens frequently when iterating over a global array. 10803dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner if (Opc == Instruction::Sub && TD) { 10903dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner GlobalValue *GV1, *GV2; 11003dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner int64_t Offs1, Offs2; 11103dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner 11203dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner if (IsConstantOffsetFromGlobal(Op0, GV1, Offs1, *TD)) 11303dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner if (IsConstantOffsetFromGlobal(Op1, GV2, Offs2, *TD) && 11403dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner GV1 == GV2) { 11503dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner // (&GV+C1) - (&GV+C2) -> C1-C2, pointer arithmetic cannot overflow. 116eed707b1e6097aac2bb6b3d47271f6300ace7f2eOwen Anderson return ConstantInt::get(Op0->getType(), Offs1-Offs2); 11703dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner } 11803dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner } 11903dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner 12003dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner return 0; 12103dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner} 12203dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner 12303dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner/// SymbolicallyEvaluateGEP - If we can symbolically evaluate the specified GEP 12403dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner/// constant expression, do so. 125f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattnerstatic Constant *SymbolicallyEvaluateGEP(Constant* const* Ops, unsigned NumOps, 12603dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner const Type *ResultTy, 127e922c0201916e0b980ab3cfe91e1413e68d55647Owen Anderson LLVMContext &Context, 12803dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner const TargetData *TD) { 12903dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner Constant *Ptr = Ops[0]; 130268e7d7a9446bb89b80472cdb7b9803f16c0191eChris Lattner if (!TD || !cast<PointerType>(Ptr->getType())->getElementType()->isSized()) 13103dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner return 0; 13203dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner 133268e7d7a9446bb89b80472cdb7b9803f16c0191eChris Lattner uint64_t BasePtr = 0; 134268e7d7a9446bb89b80472cdb7b9803f16c0191eChris Lattner if (!Ptr->isNullValue()) { 135268e7d7a9446bb89b80472cdb7b9803f16c0191eChris Lattner // If this is a inttoptr from a constant int, we can fold this as the base, 136268e7d7a9446bb89b80472cdb7b9803f16c0191eChris Lattner // otherwise we can't. 137268e7d7a9446bb89b80472cdb7b9803f16c0191eChris Lattner if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Ptr)) 138268e7d7a9446bb89b80472cdb7b9803f16c0191eChris Lattner if (CE->getOpcode() == Instruction::IntToPtr) 139268e7d7a9446bb89b80472cdb7b9803f16c0191eChris Lattner if (ConstantInt *Base = dyn_cast<ConstantInt>(CE->getOperand(0))) 140268e7d7a9446bb89b80472cdb7b9803f16c0191eChris Lattner BasePtr = Base->getZExtValue(); 141268e7d7a9446bb89b80472cdb7b9803f16c0191eChris Lattner 142268e7d7a9446bb89b80472cdb7b9803f16c0191eChris Lattner if (BasePtr == 0) 143268e7d7a9446bb89b80472cdb7b9803f16c0191eChris Lattner return 0; 14403dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner } 145268e7d7a9446bb89b80472cdb7b9803f16c0191eChris Lattner 146268e7d7a9446bb89b80472cdb7b9803f16c0191eChris Lattner // If this is a constant expr gep that is effectively computing an 147268e7d7a9446bb89b80472cdb7b9803f16c0191eChris Lattner // "offsetof", fold it into 'cast int Size to T*' instead of 'gep 0, 0, 12' 148268e7d7a9446bb89b80472cdb7b9803f16c0191eChris Lattner for (unsigned i = 1; i != NumOps; ++i) 149268e7d7a9446bb89b80472cdb7b9803f16c0191eChris Lattner if (!isa<ConstantInt>(Ops[i])) 150268e7d7a9446bb89b80472cdb7b9803f16c0191eChris Lattner return false; 151268e7d7a9446bb89b80472cdb7b9803f16c0191eChris Lattner 152268e7d7a9446bb89b80472cdb7b9803f16c0191eChris Lattner uint64_t Offset = TD->getIndexedOffset(Ptr->getType(), 153268e7d7a9446bb89b80472cdb7b9803f16c0191eChris Lattner (Value**)Ops+1, NumOps-1); 154eed707b1e6097aac2bb6b3d47271f6300ace7f2eOwen Anderson Constant *C = ConstantInt::get(TD->getIntPtrType(), Offset+BasePtr); 155baf3c404409d5e47b13984a7f95bfbd6d1f2e79eOwen Anderson return ConstantExpr::getIntToPtr(C, ResultTy); 15603dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner} 15703dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner 1581afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner/// FoldBitCast - Constant fold bitcast, symbolically evaluating it with 1591afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner/// targetdata. Return 0 if unfoldable. 1601afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattnerstatic Constant *FoldBitCast(Constant *C, const Type *DestTy, 161e922c0201916e0b980ab3cfe91e1413e68d55647Owen Anderson const TargetData &TD, LLVMContext &Context) { 1621afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner // If this is a bitcast from constant vector -> vector, fold it. 1631afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner if (ConstantVector *CV = dyn_cast<ConstantVector>(C)) { 1641afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner if (const VectorType *DestVTy = dyn_cast<VectorType>(DestTy)) { 1651afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner // If the element types match, VMCore can fold it. 1661afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner unsigned NumDstElt = DestVTy->getNumElements(); 1671afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner unsigned NumSrcElt = CV->getNumOperands(); 1681afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner if (NumDstElt == NumSrcElt) 1691afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner return 0; 1701afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner 1711afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner const Type *SrcEltTy = CV->getType()->getElementType(); 1721afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner const Type *DstEltTy = DestVTy->getElementType(); 1731afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner 1741afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner // Otherwise, we're changing the number of elements in a vector, which 1751afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner // requires endianness information to do the right thing. For example, 1761afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner // bitcast (<2 x i64> <i64 0, i64 1> to <4 x i32>) 1771afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner // folds to (little endian): 1781afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner // <4 x i32> <i32 0, i32 0, i32 1, i32 0> 1791afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner // and to (big endian): 1801afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner // <4 x i32> <i32 0, i32 0, i32 0, i32 1> 1811afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner 1821afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner // First thing is first. We only want to think about integer here, so if 1831afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner // we have something in FP form, recast it as integer. 1841afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner if (DstEltTy->isFloatingPoint()) { 1851afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner // Fold to an vector of integers with same size as our FP type. 1861afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner unsigned FPWidth = DstEltTy->getPrimitiveSizeInBits(); 187debcb01b0f0a15f568ca69e8f288fade4bfc7297Owen Anderson const Type *DestIVTy = VectorType::get( 188debcb01b0f0a15f568ca69e8f288fade4bfc7297Owen Anderson IntegerType::get(FPWidth), NumDstElt); 1891afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner // Recursively handle this integer conversion, if possible. 190508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson C = FoldBitCast(C, DestIVTy, TD, Context); 1911afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner if (!C) return 0; 1921afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner 1931afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner // Finally, VMCore can handle this now that #elts line up. 194baf3c404409d5e47b13984a7f95bfbd6d1f2e79eOwen Anderson return ConstantExpr::getBitCast(C, DestTy); 1951afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner } 1961afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner 1971afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner // Okay, we know the destination is integer, if the input is FP, convert 1981afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner // it to integer first. 1991afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner if (SrcEltTy->isFloatingPoint()) { 2001afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner unsigned FPWidth = SrcEltTy->getPrimitiveSizeInBits(); 201debcb01b0f0a15f568ca69e8f288fade4bfc7297Owen Anderson const Type *SrcIVTy = VectorType::get( 202debcb01b0f0a15f568ca69e8f288fade4bfc7297Owen Anderson IntegerType::get(FPWidth), NumSrcElt); 2031afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner // Ask VMCore to do the conversion now that #elts line up. 204baf3c404409d5e47b13984a7f95bfbd6d1f2e79eOwen Anderson C = ConstantExpr::getBitCast(C, SrcIVTy); 2051afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner CV = dyn_cast<ConstantVector>(C); 2061afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner if (!CV) return 0; // If VMCore wasn't able to fold it, bail out. 2071afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner } 2081afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner 2091afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner // Now we know that the input and output vectors are both integer vectors 2101afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner // of the same size, and that their #elements is not the same. Do the 2111afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner // conversion here, which depends on whether the input or output has 2121afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner // more elements. 2131afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner bool isLittleEndian = TD.isLittleEndian(); 2141afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner 2151afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner SmallVector<Constant*, 32> Result; 2161afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner if (NumDstElt < NumSrcElt) { 2171afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner // Handle: bitcast (<4 x i32> <i32 0, i32 1, i32 2, i32 3> to <2 x i64>) 218e922c0201916e0b980ab3cfe91e1413e68d55647Owen Anderson Constant *Zero = Context.getNullValue(DstEltTy); 2191afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner unsigned Ratio = NumSrcElt/NumDstElt; 2201afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner unsigned SrcBitSize = SrcEltTy->getPrimitiveSizeInBits(); 2211afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner unsigned SrcElt = 0; 2221afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner for (unsigned i = 0; i != NumDstElt; ++i) { 2231afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner // Build each element of the result. 2241afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner Constant *Elt = Zero; 2251afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner unsigned ShiftAmt = isLittleEndian ? 0 : SrcBitSize*(Ratio-1); 2261afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner for (unsigned j = 0; j != Ratio; ++j) { 2271afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner Constant *Src = dyn_cast<ConstantInt>(CV->getOperand(SrcElt++)); 2281afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner if (!Src) return 0; // Reject constantexpr elements. 2291afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner 2301afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner // Zero extend the element to the right size. 231baf3c404409d5e47b13984a7f95bfbd6d1f2e79eOwen Anderson Src = ConstantExpr::getZExt(Src, Elt->getType()); 2321afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner 2331afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner // Shift it to the right place, depending on endianness. 234baf3c404409d5e47b13984a7f95bfbd6d1f2e79eOwen Anderson Src = ConstantExpr::getShl(Src, 235eed707b1e6097aac2bb6b3d47271f6300ace7f2eOwen Anderson ConstantInt::get(Src->getType(), ShiftAmt)); 2361afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner ShiftAmt += isLittleEndian ? SrcBitSize : -SrcBitSize; 2371afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner 2381afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner // Mix it in. 239baf3c404409d5e47b13984a7f95bfbd6d1f2e79eOwen Anderson Elt = ConstantExpr::getOr(Elt, Src); 2401afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner } 2411afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner Result.push_back(Elt); 2421afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner } 2431afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner } else { 2441afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner // Handle: bitcast (<2 x i64> <i64 0, i64 1> to <4 x i32>) 2451afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner unsigned Ratio = NumDstElt/NumSrcElt; 2461afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner unsigned DstBitSize = DstEltTy->getPrimitiveSizeInBits(); 2471afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner 2481afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner // Loop over each source value, expanding into multiple results. 2491afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner for (unsigned i = 0; i != NumSrcElt; ++i) { 2501afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner Constant *Src = dyn_cast<ConstantInt>(CV->getOperand(i)); 2511afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner if (!Src) return 0; // Reject constantexpr elements. 2521afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner 2531afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner unsigned ShiftAmt = isLittleEndian ? 0 : DstBitSize*(Ratio-1); 2541afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner for (unsigned j = 0; j != Ratio; ++j) { 2551afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner // Shift the piece of the value into the right place, depending on 2561afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner // endianness. 257baf3c404409d5e47b13984a7f95bfbd6d1f2e79eOwen Anderson Constant *Elt = ConstantExpr::getLShr(Src, 258eed707b1e6097aac2bb6b3d47271f6300ace7f2eOwen Anderson ConstantInt::get(Src->getType(), ShiftAmt)); 2591afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner ShiftAmt += isLittleEndian ? DstBitSize : -DstBitSize; 2601afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner 2611afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner // Truncate and remember this piece. 262baf3c404409d5e47b13984a7f95bfbd6d1f2e79eOwen Anderson Result.push_back(ConstantExpr::getTrunc(Elt, DstEltTy)); 2631afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner } 2641afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner } 2651afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner } 2661afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner 267af7ec975870f92245f1f1484ac80a1e2db6a0afaOwen Anderson return ConstantVector::get(Result.data(), Result.size()); 2681afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner } 2691afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner } 2701afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner 2711afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner return 0; 2721afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner} 2731afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner 27403dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner 27503dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner//===----------------------------------------------------------------------===// 27603dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner// Constant Folding public APIs 27703dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner//===----------------------------------------------------------------------===// 27803dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner 27903dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner 2805520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner/// ConstantFoldInstruction - Attempt to constant fold the specified 2815520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner/// instruction. If successful, the constant result is returned, if not, null 2825520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner/// is returned. Note that this function can only fail when attempting to fold 2835520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner/// instructions like loads and stores, which have no constant expression form. 2845520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner/// 285e922c0201916e0b980ab3cfe91e1413e68d55647Owen AndersonConstant *llvm::ConstantFoldInstruction(Instruction *I, LLVMContext &Context, 286508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson const TargetData *TD) { 2875520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner if (PHINode *PN = dyn_cast<PHINode>(I)) { 2885520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner if (PN->getNumIncomingValues() == 0) 289e922c0201916e0b980ab3cfe91e1413e68d55647Owen Anderson return Context.getUndef(PN->getType()); 2905520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner 2915520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner Constant *Result = dyn_cast<Constant>(PN->getIncomingValue(0)); 2925520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner if (Result == 0) return 0; 2935520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner 2945520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner // Handle PHI nodes specially here... 2955520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner for (unsigned i = 1, e = PN->getNumIncomingValues(); i != e; ++i) 2965520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner if (PN->getIncomingValue(i) != Result && PN->getIncomingValue(i) != PN) 2975520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner return 0; // Not all the same incoming constants... 2985520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner 2995520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner // If we reach here, all incoming values are the same constant. 3005520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner return Result; 3015520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner } 3025520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner 3035520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner // Scan the operand list, checking to see if they are all constants, if so, 3045520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner // hand off to ConstantFoldInstOperands. 3055520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner SmallVector<Constant*, 8> Ops; 306de2d74b213844b17eb5327fba27f21e699d3af66Gabor Greif for (User::op_iterator i = I->op_begin(), e = I->op_end(); i != e; ++i) 307de2d74b213844b17eb5327fba27f21e699d3af66Gabor Greif if (Constant *Op = dyn_cast<Constant>(*i)) 3085520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner Ops.push_back(Op); 3095520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner else 3105520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner return 0; // All operands not constant! 3115520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner 312f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner if (const CmpInst *CI = dyn_cast<CmpInst>(I)) 313f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner return ConstantFoldCompareInstOperands(CI->getPredicate(), 314508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson Ops.data(), Ops.size(), 315508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson Context, TD); 316f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner else 317f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner return ConstantFoldInstOperands(I->getOpcode(), I->getType(), 318508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson Ops.data(), Ops.size(), Context, TD); 3195520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner} 3205520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner 3213dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick Lewycky/// ConstantFoldConstantExpression - Attempt to fold the constant expression 3223dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick Lewycky/// using the specified TargetData. If successful, the constant result is 3233dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick Lewycky/// result is returned, if not, null is returned. 3243dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick LewyckyConstant *llvm::ConstantFoldConstantExpression(ConstantExpr *CE, 325e922c0201916e0b980ab3cfe91e1413e68d55647Owen Anderson LLVMContext &Context, 3263dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick Lewycky const TargetData *TD) { 3273dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick Lewycky SmallVector<Constant*, 8> Ops; 3283dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick Lewycky for (User::op_iterator i = CE->op_begin(), e = CE->op_end(); i != e; ++i) 3293dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick Lewycky Ops.push_back(cast<Constant>(*i)); 3303dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick Lewycky 3313dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick Lewycky if (CE->isCompare()) 3323dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick Lewycky return ConstantFoldCompareInstOperands(CE->getPredicate(), 333508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson Ops.data(), Ops.size(), 334508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson Context, TD); 3353dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick Lewycky else 3363dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick Lewycky return ConstantFoldInstOperands(CE->getOpcode(), CE->getType(), 337508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson Ops.data(), Ops.size(), Context, TD); 3383dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick Lewycky} 3393dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick Lewycky 3405520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner/// ConstantFoldInstOperands - Attempt to constant fold an instruction with the 3415520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner/// specified opcode and operands. If successful, the constant result is 3425520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner/// returned, if not, null is returned. Note that this function can fail when 3435520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner/// attempting to fold instructions like loads and stores, which have no 3445520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner/// constant expression form. 3455520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner/// 346f286f6fd93d569befe6e77c94a947e6e04e95685Chris LattnerConstant *llvm::ConstantFoldInstOperands(unsigned Opcode, const Type *DestTy, 347f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner Constant* const* Ops, unsigned NumOps, 348e922c0201916e0b980ab3cfe91e1413e68d55647Owen Anderson LLVMContext &Context, 3495520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner const TargetData *TD) { 35003dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner // Handle easy binops first. 351f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner if (Instruction::isBinaryOp(Opcode)) { 35203dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner if (isa<ConstantExpr>(Ops[0]) || isa<ConstantExpr>(Ops[1])) 353508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson if (Constant *C = SymbolicallyEvaluateBinop(Opcode, Ops[0], Ops[1], TD, 354508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson Context)) 35503dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner return C; 35603dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner 357baf3c404409d5e47b13984a7f95bfbd6d1f2e79eOwen Anderson return ConstantExpr::get(Opcode, Ops[0], Ops[1]); 35803dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner } 3595520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner 360f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner switch (Opcode) { 3615520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner default: return 0; 3625520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner case Instruction::Call: 3635520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner if (Function *F = dyn_cast<Function>(Ops[0])) 3645520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner if (canConstantFoldCallTo(F)) 365ad58eb34342f70f094008e6d08cb4ed814754e64Chris Lattner return ConstantFoldCall(F, Ops+1, NumOps-1); 3665520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner return 0; 3675520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner case Instruction::ICmp: 3685520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner case Instruction::FCmp: 369c23197a26f34f559ea9797de51e187087c039c42Torok Edwin llvm_unreachable("This function is invalid for compares: no predicate specified"); 370001f7534e0311508cc93831a595785bb177f8a18Chris Lattner case Instruction::PtrToInt: 371001f7534e0311508cc93831a595785bb177f8a18Chris Lattner // If the input is a inttoptr, eliminate the pair. This requires knowing 372001f7534e0311508cc93831a595785bb177f8a18Chris Lattner // the width of a pointer, so it can't be done in ConstantExpr::getCast. 373001f7534e0311508cc93831a595785bb177f8a18Chris Lattner if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Ops[0])) { 374001f7534e0311508cc93831a595785bb177f8a18Chris Lattner if (TD && CE->getOpcode() == Instruction::IntToPtr) { 375001f7534e0311508cc93831a595785bb177f8a18Chris Lattner Constant *Input = CE->getOperand(0); 3766de29f8d960505421d61c80cdb738e16720b6c0eDan Gohman unsigned InWidth = Input->getType()->getScalarSizeInBits(); 37704aa2c3520c049333ca216fb794d700310c4a33dNick Lewycky if (TD->getPointerSizeInBits() < InWidth) { 37804aa2c3520c049333ca216fb794d700310c4a33dNick Lewycky Constant *Mask = 379eed707b1e6097aac2bb6b3d47271f6300ace7f2eOwen Anderson ConstantInt::get(Context, APInt::getLowBitsSet(InWidth, 38004aa2c3520c049333ca216fb794d700310c4a33dNick Lewycky TD->getPointerSizeInBits())); 381baf3c404409d5e47b13984a7f95bfbd6d1f2e79eOwen Anderson Input = ConstantExpr::getAnd(Input, Mask); 38204aa2c3520c049333ca216fb794d700310c4a33dNick Lewycky } 383001f7534e0311508cc93831a595785bb177f8a18Chris Lattner // Do a zext or trunc to get to the dest size. 384baf3c404409d5e47b13984a7f95bfbd6d1f2e79eOwen Anderson return ConstantExpr::getIntegerCast(Input, DestTy, false); 385001f7534e0311508cc93831a595785bb177f8a18Chris Lattner } 386001f7534e0311508cc93831a595785bb177f8a18Chris Lattner } 387baf3c404409d5e47b13984a7f95bfbd6d1f2e79eOwen Anderson return ConstantExpr::getCast(Opcode, Ops[0], DestTy); 388001f7534e0311508cc93831a595785bb177f8a18Chris Lattner case Instruction::IntToPtr: 38981b06be055e74a3c23a1c8f17ead97f9f76335eeDuncan Sands // If the input is a ptrtoint, turn the pair into a ptr to ptr bitcast if 39081b06be055e74a3c23a1c8f17ead97f9f76335eeDuncan Sands // the int size is >= the ptr size. This requires knowing the width of a 39181b06be055e74a3c23a1c8f17ead97f9f76335eeDuncan Sands // pointer, so it can't be done in ConstantExpr::getCast. 39281b06be055e74a3c23a1c8f17ead97f9f76335eeDuncan Sands if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Ops[0])) { 3939a38e3e3991ea443e555d8060f91202a786acdd4Dan Gohman if (TD && 39481b06be055e74a3c23a1c8f17ead97f9f76335eeDuncan Sands TD->getPointerSizeInBits() <= 3956de29f8d960505421d61c80cdb738e16720b6c0eDan Gohman CE->getType()->getScalarSizeInBits()) { 3969a38e3e3991ea443e555d8060f91202a786acdd4Dan Gohman if (CE->getOpcode() == Instruction::PtrToInt) { 3979a38e3e3991ea443e555d8060f91202a786acdd4Dan Gohman Constant *Input = CE->getOperand(0); 398508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson Constant *C = FoldBitCast(Input, DestTy, *TD, Context); 399baf3c404409d5e47b13984a7f95bfbd6d1f2e79eOwen Anderson return C ? C : ConstantExpr::getBitCast(Input, DestTy); 4009a38e3e3991ea443e555d8060f91202a786acdd4Dan Gohman } 4019a38e3e3991ea443e555d8060f91202a786acdd4Dan Gohman // If there's a constant offset added to the integer value before 4029a38e3e3991ea443e555d8060f91202a786acdd4Dan Gohman // it is casted back to a pointer, see if the expression can be 4039a38e3e3991ea443e555d8060f91202a786acdd4Dan Gohman // converted into a GEP. 4049a38e3e3991ea443e555d8060f91202a786acdd4Dan Gohman if (CE->getOpcode() == Instruction::Add) 4059a38e3e3991ea443e555d8060f91202a786acdd4Dan Gohman if (ConstantInt *L = dyn_cast<ConstantInt>(CE->getOperand(0))) 4069a38e3e3991ea443e555d8060f91202a786acdd4Dan Gohman if (ConstantExpr *R = dyn_cast<ConstantExpr>(CE->getOperand(1))) 4079a38e3e3991ea443e555d8060f91202a786acdd4Dan Gohman if (R->getOpcode() == Instruction::PtrToInt) 4089a38e3e3991ea443e555d8060f91202a786acdd4Dan Gohman if (GlobalVariable *GV = 4099a38e3e3991ea443e555d8060f91202a786acdd4Dan Gohman dyn_cast<GlobalVariable>(R->getOperand(0))) { 4109a38e3e3991ea443e555d8060f91202a786acdd4Dan Gohman const PointerType *GVTy = cast<PointerType>(GV->getType()); 4119a38e3e3991ea443e555d8060f91202a786acdd4Dan Gohman if (const ArrayType *AT = 4129a38e3e3991ea443e555d8060f91202a786acdd4Dan Gohman dyn_cast<ArrayType>(GVTy->getElementType())) { 4139a38e3e3991ea443e555d8060f91202a786acdd4Dan Gohman const Type *ElTy = AT->getElementType(); 414777d2306b36816a53bc1ae1244c0dc7d998ae691Duncan Sands uint64_t AllocSize = TD->getTypeAllocSize(ElTy); 415777d2306b36816a53bc1ae1244c0dc7d998ae691Duncan Sands APInt PSA(L->getValue().getBitWidth(), AllocSize); 4169a38e3e3991ea443e555d8060f91202a786acdd4Dan Gohman if (ElTy == cast<PointerType>(DestTy)->getElementType() && 4179a38e3e3991ea443e555d8060f91202a786acdd4Dan Gohman L->getValue().urem(PSA) == 0) { 4189a38e3e3991ea443e555d8060f91202a786acdd4Dan Gohman APInt ElemIdx = L->getValue().udiv(PSA); 4199a38e3e3991ea443e555d8060f91202a786acdd4Dan Gohman if (ElemIdx.ult(APInt(ElemIdx.getBitWidth(), 4209a38e3e3991ea443e555d8060f91202a786acdd4Dan Gohman AT->getNumElements()))) { 4219a38e3e3991ea443e555d8060f91202a786acdd4Dan Gohman Constant *Index[] = { 422e922c0201916e0b980ab3cfe91e1413e68d55647Owen Anderson Context.getNullValue(CE->getType()), 423eed707b1e6097aac2bb6b3d47271f6300ace7f2eOwen Anderson ConstantInt::get(Context, ElemIdx) 4249a38e3e3991ea443e555d8060f91202a786acdd4Dan Gohman }; 425508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson return 426baf3c404409d5e47b13984a7f95bfbd6d1f2e79eOwen Anderson ConstantExpr::getGetElementPtr(GV, &Index[0], 2); 4279a38e3e3991ea443e555d8060f91202a786acdd4Dan Gohman } 4289a38e3e3991ea443e555d8060f91202a786acdd4Dan Gohman } 4299a38e3e3991ea443e555d8060f91202a786acdd4Dan Gohman } 4309a38e3e3991ea443e555d8060f91202a786acdd4Dan Gohman } 43181b06be055e74a3c23a1c8f17ead97f9f76335eeDuncan Sands } 43281b06be055e74a3c23a1c8f17ead97f9f76335eeDuncan Sands } 433baf3c404409d5e47b13984a7f95bfbd6d1f2e79eOwen Anderson return ConstantExpr::getCast(Opcode, Ops[0], DestTy); 4345520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner case Instruction::Trunc: 4355520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner case Instruction::ZExt: 4365520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner case Instruction::SExt: 4375520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner case Instruction::FPTrunc: 4385520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner case Instruction::FPExt: 4395520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner case Instruction::UIToFP: 4405520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner case Instruction::SIToFP: 4415520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner case Instruction::FPToUI: 4425520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner case Instruction::FPToSI: 443baf3c404409d5e47b13984a7f95bfbd6d1f2e79eOwen Anderson return ConstantExpr::getCast(Opcode, Ops[0], DestTy); 4445520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner case Instruction::BitCast: 4451afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner if (TD) 446508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson if (Constant *C = FoldBitCast(Ops[0], DestTy, *TD, Context)) 4471afab9c1e0ae2d145ce01718aa14065393117e70Chris Lattner return C; 448baf3c404409d5e47b13984a7f95bfbd6d1f2e79eOwen Anderson return ConstantExpr::getBitCast(Ops[0], DestTy); 4495520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner case Instruction::Select: 450baf3c404409d5e47b13984a7f95bfbd6d1f2e79eOwen Anderson return ConstantExpr::getSelect(Ops[0], Ops[1], Ops[2]); 4515520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner case Instruction::ExtractElement: 452baf3c404409d5e47b13984a7f95bfbd6d1f2e79eOwen Anderson return ConstantExpr::getExtractElement(Ops[0], Ops[1]); 4535520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner case Instruction::InsertElement: 454baf3c404409d5e47b13984a7f95bfbd6d1f2e79eOwen Anderson return ConstantExpr::getInsertElement(Ops[0], Ops[1], Ops[2]); 4555520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner case Instruction::ShuffleVector: 456baf3c404409d5e47b13984a7f95bfbd6d1f2e79eOwen Anderson return ConstantExpr::getShuffleVector(Ops[0], Ops[1], Ops[2]); 4575520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner case Instruction::GetElementPtr: 458508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson if (Constant *C = SymbolicallyEvaluateGEP(Ops, NumOps, DestTy, Context, TD)) 45903dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner return C; 46003dd25ca964813c8b9fe14479443b9c21fb92c55Chris Lattner 461baf3c404409d5e47b13984a7f95bfbd6d1f2e79eOwen Anderson return ConstantExpr::getGetElementPtr(Ops[0], Ops+1, NumOps-1); 4625520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner } 4635520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner} 4645520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner 465f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner/// ConstantFoldCompareInstOperands - Attempt to constant fold a compare 466f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner/// instruction (icmp/fcmp) with the specified operands. If it fails, it 467f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner/// returns a constant expression of the specified operands. 468f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner/// 469f286f6fd93d569befe6e77c94a947e6e04e95685Chris LattnerConstant *llvm::ConstantFoldCompareInstOperands(unsigned Predicate, 470f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner Constant*const * Ops, 471f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner unsigned NumOps, 472e922c0201916e0b980ab3cfe91e1413e68d55647Owen Anderson LLVMContext &Context, 473f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner const TargetData *TD) { 474f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner // fold: icmp (inttoptr x), null -> icmp x, 0 475f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner // fold: icmp (ptrtoint x), 0 -> icmp x, null 4763dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick Lewycky // fold: icmp (inttoptr x), (inttoptr y) -> icmp trunc/zext x, trunc/zext y 477f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner // fold: icmp (ptrtoint x), (ptrtoint y) -> icmp x, y 478f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner // 479f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner // ConstantExpr::getCompare cannot do this, because it doesn't have TD 480f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner // around to know if bit truncation is happening. 481f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner if (ConstantExpr *CE0 = dyn_cast<ConstantExpr>(Ops[0])) { 482f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner if (TD && Ops[1]->isNullValue()) { 483f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner const Type *IntPtrTy = TD->getIntPtrType(); 484f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner if (CE0->getOpcode() == Instruction::IntToPtr) { 485f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner // Convert the integer value to the right size to ensure we get the 486f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner // proper extension or truncation. 487baf3c404409d5e47b13984a7f95bfbd6d1f2e79eOwen Anderson Constant *C = ConstantExpr::getIntegerCast(CE0->getOperand(0), 488f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner IntPtrTy, false); 489e922c0201916e0b980ab3cfe91e1413e68d55647Owen Anderson Constant *NewOps[] = { C, Context.getNullValue(C->getType()) }; 490508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson return ConstantFoldCompareInstOperands(Predicate, NewOps, 2, 491508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson Context, TD); 492f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner } 493f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner 494f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner // Only do this transformation if the int is intptrty in size, otherwise 495f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner // there is a truncation or extension that we aren't modeling. 496f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner if (CE0->getOpcode() == Instruction::PtrToInt && 497f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner CE0->getType() == IntPtrTy) { 498f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner Constant *C = CE0->getOperand(0); 499e922c0201916e0b980ab3cfe91e1413e68d55647Owen Anderson Constant *NewOps[] = { C, Context.getNullValue(C->getType()) }; 500f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner // FIXME! 501508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson return ConstantFoldCompareInstOperands(Predicate, NewOps, 2, 502508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson Context, TD); 503f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner } 504f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner } 505f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner 5063dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick Lewycky if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(Ops[1])) { 5073dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick Lewycky if (TD && CE0->getOpcode() == CE1->getOpcode()) { 5083dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick Lewycky const Type *IntPtrTy = TD->getIntPtrType(); 5093dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick Lewycky 5103dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick Lewycky if (CE0->getOpcode() == Instruction::IntToPtr) { 5113dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick Lewycky // Convert the integer value to the right size to ensure we get the 5123dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick Lewycky // proper extension or truncation. 513baf3c404409d5e47b13984a7f95bfbd6d1f2e79eOwen Anderson Constant *C0 = ConstantExpr::getIntegerCast(CE0->getOperand(0), 5143dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick Lewycky IntPtrTy, false); 515baf3c404409d5e47b13984a7f95bfbd6d1f2e79eOwen Anderson Constant *C1 = ConstantExpr::getIntegerCast(CE1->getOperand(0), 5163dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick Lewycky IntPtrTy, false); 5173dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick Lewycky Constant *NewOps[] = { C0, C1 }; 518508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson return ConstantFoldCompareInstOperands(Predicate, NewOps, 2, 519508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson Context, TD); 5203dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick Lewycky } 5213dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick Lewycky 5223dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick Lewycky // Only do this transformation if the int is intptrty in size, otherwise 5233dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick Lewycky // there is a truncation or extension that we aren't modeling. 5243dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick Lewycky if ((CE0->getOpcode() == Instruction::PtrToInt && 5253dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick Lewycky CE0->getType() == IntPtrTy && 5263dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick Lewycky CE0->getOperand(0)->getType() == CE1->getOperand(0)->getType())) { 5273dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick Lewycky Constant *NewOps[] = { 5283dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick Lewycky CE0->getOperand(0), CE1->getOperand(0) 5293dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick Lewycky }; 530508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson return ConstantFoldCompareInstOperands(Predicate, NewOps, 2, 531508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson Context, TD); 5323dfd7bf5110c47e99fd0fcce96122b90f699ca3aNick Lewycky } 533f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner } 534f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner } 535f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner } 536baf3c404409d5e47b13984a7f95bfbd6d1f2e79eOwen Anderson return ConstantExpr::getCompare(Predicate, Ops[0], Ops[1]); 537f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner} 538f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner 539f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner 5405520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner/// ConstantFoldLoadThroughGEPConstantExpr - Given a constant and a 5415520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner/// getelementptr constantexpr, return the constant value being addressed by the 5425520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner/// constant expression, or null if something is funny and we can't decide. 5435520732b24a5a321140dd79af70d321c7ff3dec9Chris LattnerConstant *llvm::ConstantFoldLoadThroughGEPConstantExpr(Constant *C, 544508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson ConstantExpr *CE, 545e922c0201916e0b980ab3cfe91e1413e68d55647Owen Anderson LLVMContext &Context) { 546e922c0201916e0b980ab3cfe91e1413e68d55647Owen Anderson if (CE->getOperand(1) != Context.getNullValue(CE->getOperand(1)->getType())) 5475520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner return 0; // Do not allow stepping over the value! 5485520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner 5495520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner // Loop over all of the operands, tracking down which value we are 5505520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner // addressing... 5515520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner gep_type_iterator I = gep_type_begin(CE), E = gep_type_end(CE); 5525520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner for (++I; I != E; ++I) 5535520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner if (const StructType *STy = dyn_cast<StructType>(*I)) { 5545520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner ConstantInt *CU = cast<ConstantInt>(I.getOperand()); 5555520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner assert(CU->getZExtValue() < STy->getNumElements() && 5565520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner "Struct index out of range!"); 5575520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner unsigned El = (unsigned)CU->getZExtValue(); 5585520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner if (ConstantStruct *CS = dyn_cast<ConstantStruct>(C)) { 5595520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner C = CS->getOperand(El); 5605520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner } else if (isa<ConstantAggregateZero>(C)) { 561e922c0201916e0b980ab3cfe91e1413e68d55647Owen Anderson C = Context.getNullValue(STy->getElementType(El)); 5625520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner } else if (isa<UndefValue>(C)) { 563e922c0201916e0b980ab3cfe91e1413e68d55647Owen Anderson C = Context.getUndef(STy->getElementType(El)); 5645520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner } else { 5655520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner return 0; 5665520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner } 5675520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner } else if (ConstantInt *CI = dyn_cast<ConstantInt>(I.getOperand())) { 5685520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner if (const ArrayType *ATy = dyn_cast<ArrayType>(*I)) { 5695520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner if (CI->getZExtValue() >= ATy->getNumElements()) 5705520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner return 0; 5715520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner if (ConstantArray *CA = dyn_cast<ConstantArray>(C)) 5725520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner C = CA->getOperand(CI->getZExtValue()); 5735520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner else if (isa<ConstantAggregateZero>(C)) 574e922c0201916e0b980ab3cfe91e1413e68d55647Owen Anderson C = Context.getNullValue(ATy->getElementType()); 5755520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner else if (isa<UndefValue>(C)) 576e922c0201916e0b980ab3cfe91e1413e68d55647Owen Anderson C = Context.getUndef(ATy->getElementType()); 5775520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner else 5785520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner return 0; 5799d6565a5b1fbc4286d6ee638d8f47a3171a9ed7eReid Spencer } else if (const VectorType *PTy = dyn_cast<VectorType>(*I)) { 5805520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner if (CI->getZExtValue() >= PTy->getNumElements()) 5815520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner return 0; 5829d6565a5b1fbc4286d6ee638d8f47a3171a9ed7eReid Spencer if (ConstantVector *CP = dyn_cast<ConstantVector>(C)) 5835520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner C = CP->getOperand(CI->getZExtValue()); 5845520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner else if (isa<ConstantAggregateZero>(C)) 585e922c0201916e0b980ab3cfe91e1413e68d55647Owen Anderson C = Context.getNullValue(PTy->getElementType()); 5865520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner else if (isa<UndefValue>(C)) 587e922c0201916e0b980ab3cfe91e1413e68d55647Owen Anderson C = Context.getUndef(PTy->getElementType()); 5885520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner else 5895520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner return 0; 5905520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner } else { 5915520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner return 0; 5925520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner } 5935520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner } else { 5945520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner return 0; 5955520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner } 5965520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner return C; 5975520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner} 5985520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner 5995520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner 600bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell//===----------------------------------------------------------------------===// 6015520732b24a5a321140dd79af70d321c7ff3dec9Chris Lattner// Constant Folding for Calls 602bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell// 603bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell 604bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell/// canConstantFoldCallTo - Return true if its even possible to fold a call to 605bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell/// the specified function. 606bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswellbool 607fa9b80eb64127b3d9691e18537975635520e51e9Dan Gohmanllvm::canConstantFoldCallTo(const Function *F) { 608bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell switch (F->getIntrinsicID()) { 6099ab7fb3ba47442d521a5bed09a27a5e8e7a786edDale Johannesen case Intrinsic::sqrt: 6109ab7fb3ba47442d521a5bed09a27a5e8e7a786edDale Johannesen case Intrinsic::powi: 611e9391fd9b52e93717b365bdd05c471101323a4dfReid Spencer case Intrinsic::bswap: 612e9391fd9b52e93717b365bdd05c471101323a4dfReid Spencer case Intrinsic::ctpop: 613e9391fd9b52e93717b365bdd05c471101323a4dfReid Spencer case Intrinsic::ctlz: 614e9391fd9b52e93717b365bdd05c471101323a4dfReid Spencer case Intrinsic::cttz: 615bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell return true; 616bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell default: break; 617bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell } 618bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell 6196f532a988e5c02fcb271fb65e9e7b83f0147d3f2Chris Lattner if (!F->hasName()) return false; 620f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar StringRef Name = F->getName(); 621c5f6a1f9d61d74017d90e149728cb3d283e0a0e0Chris Lattner 622c5f6a1f9d61d74017d90e149728cb3d283e0a0e0Chris Lattner // In these cases, the check of the length is required. We don't want to 623c5f6a1f9d61d74017d90e149728cb3d283e0a0e0Chris Lattner // return true for a name like "cos\0blah" which strcmp would return equal to 624c5f6a1f9d61d74017d90e149728cb3d283e0a0e0Chris Lattner // "cos", but has length 8. 625f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar switch (Name[0]) { 626c5f6a1f9d61d74017d90e149728cb3d283e0a0e0Chris Lattner default: return false; 627c5f6a1f9d61d74017d90e149728cb3d283e0a0e0Chris Lattner case 'a': 628f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar return Name == "acos" || Name == "asin" || 629f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar Name == "atan" || Name == "atan2"; 630c5f6a1f9d61d74017d90e149728cb3d283e0a0e0Chris Lattner case 'c': 631f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar return Name == "cos" || Name == "ceil" || Name == "cosf" || Name == "cosh"; 632c5f6a1f9d61d74017d90e149728cb3d283e0a0e0Chris Lattner case 'e': 633f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar return Name == "exp"; 634c5f6a1f9d61d74017d90e149728cb3d283e0a0e0Chris Lattner case 'f': 635f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar return Name == "fabs" || Name == "fmod" || Name == "floor"; 636c5f6a1f9d61d74017d90e149728cb3d283e0a0e0Chris Lattner case 'l': 637f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar return Name == "log" || Name == "log10"; 638c5f6a1f9d61d74017d90e149728cb3d283e0a0e0Chris Lattner case 'p': 639f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar return Name == "pow"; 640c5f6a1f9d61d74017d90e149728cb3d283e0a0e0Chris Lattner case 's': 641f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar return Name == "sin" || Name == "sinh" || Name == "sqrt" || 642f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar Name == "sinf" || Name == "sqrtf"; 643c5f6a1f9d61d74017d90e149728cb3d283e0a0e0Chris Lattner case 't': 644f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar return Name == "tan" || Name == "tanh"; 645bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell } 646bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell} 647bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell 64872d88ae5447a3929c97e88f4c806213847b5d988Chris Lattnerstatic Constant *ConstantFoldFP(double (*NativeFP)(double), double V, 649e922c0201916e0b980ab3cfe91e1413e68d55647Owen Anderson const Type *Ty, LLVMContext &Context) { 650bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell errno = 0; 651bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell V = NativeFP(V); 652f19f58a9360927f8ef50b9a029e8efb780d3d8a8Chris Lattner if (errno != 0) { 653f19f58a9360927f8ef50b9a029e8efb780d3d8a8Chris Lattner errno = 0; 654f19f58a9360927f8ef50b9a029e8efb780d3d8a8Chris Lattner return 0; 65543421b3dd70af5b70e71816521f37502c397cc65Dale Johannesen } 656f19f58a9360927f8ef50b9a029e8efb780d3d8a8Chris Lattner 657f19f58a9360927f8ef50b9a029e8efb780d3d8a8Chris Lattner if (Ty == Type::FloatTy) 6586f83c9c6ef0e7f79825a0a8f22941815e4b684c7Owen Anderson return ConstantFP::get(Context, APFloat((float)V)); 659f19f58a9360927f8ef50b9a029e8efb780d3d8a8Chris Lattner if (Ty == Type::DoubleTy) 6606f83c9c6ef0e7f79825a0a8f22941815e4b684c7Owen Anderson return ConstantFP::get(Context, APFloat(V)); 661c23197a26f34f559ea9797de51e187087c039c42Torok Edwin llvm_unreachable("Can only constant fold float/double"); 66233e456d5f3909e0c7b96e04e5674c25a182da100Gabor Greif return 0; // dummy return to suppress warning 663bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell} 664bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell 665384152444d22d356f7b4090a158da4cbc1f79464Dan Gohmanstatic Constant *ConstantFoldBinaryFP(double (*NativeFP)(double, double), 666384152444d22d356f7b4090a158da4cbc1f79464Dan Gohman double V, double W, 667508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson const Type *Ty, 668e922c0201916e0b980ab3cfe91e1413e68d55647Owen Anderson LLVMContext &Context) { 669384152444d22d356f7b4090a158da4cbc1f79464Dan Gohman errno = 0; 670384152444d22d356f7b4090a158da4cbc1f79464Dan Gohman V = NativeFP(V, W); 671f19f58a9360927f8ef50b9a029e8efb780d3d8a8Chris Lattner if (errno != 0) { 672f19f58a9360927f8ef50b9a029e8efb780d3d8a8Chris Lattner errno = 0; 673f19f58a9360927f8ef50b9a029e8efb780d3d8a8Chris Lattner return 0; 67443421b3dd70af5b70e71816521f37502c397cc65Dale Johannesen } 675f19f58a9360927f8ef50b9a029e8efb780d3d8a8Chris Lattner 676f19f58a9360927f8ef50b9a029e8efb780d3d8a8Chris Lattner if (Ty == Type::FloatTy) 6776f83c9c6ef0e7f79825a0a8f22941815e4b684c7Owen Anderson return ConstantFP::get(Context, APFloat((float)V)); 678f19f58a9360927f8ef50b9a029e8efb780d3d8a8Chris Lattner if (Ty == Type::DoubleTy) 6796f83c9c6ef0e7f79825a0a8f22941815e4b684c7Owen Anderson return ConstantFP::get(Context, APFloat(V)); 680c23197a26f34f559ea9797de51e187087c039c42Torok Edwin llvm_unreachable("Can only constant fold float/double"); 68133e456d5f3909e0c7b96e04e5674c25a182da100Gabor Greif return 0; // dummy return to suppress warning 682384152444d22d356f7b4090a158da4cbc1f79464Dan Gohman} 683384152444d22d356f7b4090a158da4cbc1f79464Dan Gohman 684bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell/// ConstantFoldCall - Attempt to constant fold a call to the specified function 685bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell/// with the specified arguments, returning null if unsuccessful. 68643421b3dd70af5b70e71816521f37502c397cc65Dale Johannesen 687bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John CriswellConstant * 688f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattnerllvm::ConstantFoldCall(Function *F, 689f286f6fd93d569befe6e77c94a947e6e04e95685Chris Lattner Constant* const* Operands, unsigned NumOperands) { 6906f532a988e5c02fcb271fb65e9e7b83f0147d3f2Chris Lattner if (!F->hasName()) return 0; 691e922c0201916e0b980ab3cfe91e1413e68d55647Owen Anderson LLVMContext &Context = F->getContext(); 692f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar StringRef Name = F->getName(); 693c5f6a1f9d61d74017d90e149728cb3d283e0a0e0Chris Lattner 694bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell const Type *Ty = F->getReturnType(); 69572d88ae5447a3929c97e88f4c806213847b5d988Chris Lattner if (NumOperands == 1) { 696bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell if (ConstantFP *Op = dyn_cast<ConstantFP>(Operands[0])) { 69743421b3dd70af5b70e71816521f37502c397cc65Dale Johannesen if (Ty!=Type::FloatTy && Ty!=Type::DoubleTy) 69843421b3dd70af5b70e71816521f37502c397cc65Dale Johannesen return 0; 69943421b3dd70af5b70e71816521f37502c397cc65Dale Johannesen /// Currently APFloat versions of these functions do not exist, so we use 70043421b3dd70af5b70e71816521f37502c397cc65Dale Johannesen /// the host native double versions. Float versions are not called 70143421b3dd70af5b70e71816521f37502c397cc65Dale Johannesen /// directly but for all these it is true (float)(f((double)arg)) == 70243421b3dd70af5b70e71816521f37502c397cc65Dale Johannesen /// f(arg). Long double not supported yet. 70343421b3dd70af5b70e71816521f37502c397cc65Dale Johannesen double V = Ty==Type::FloatTy ? (double)Op->getValueAPF().convertToFloat(): 70443421b3dd70af5b70e71816521f37502c397cc65Dale Johannesen Op->getValueAPF().convertToDouble(); 705f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar switch (Name[0]) { 706c5f6a1f9d61d74017d90e149728cb3d283e0a0e0Chris Lattner case 'a': 707f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar if (Name == "acos") 708508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson return ConstantFoldFP(acos, V, Ty, Context); 709f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar else if (Name == "asin") 710508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson return ConstantFoldFP(asin, V, Ty, Context); 711f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar else if (Name == "atan") 712508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson return ConstantFoldFP(atan, V, Ty, Context); 713c5f6a1f9d61d74017d90e149728cb3d283e0a0e0Chris Lattner break; 714c5f6a1f9d61d74017d90e149728cb3d283e0a0e0Chris Lattner case 'c': 715f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar if (Name == "ceil") 716508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson return ConstantFoldFP(ceil, V, Ty, Context); 717f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar else if (Name == "cos") 718508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson return ConstantFoldFP(cos, V, Ty, Context); 719f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar else if (Name == "cosh") 720508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson return ConstantFoldFP(cosh, V, Ty, Context); 721f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar else if (Name == "cosf") 722508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson return ConstantFoldFP(cos, V, Ty, Context); 723c5f6a1f9d61d74017d90e149728cb3d283e0a0e0Chris Lattner break; 724c5f6a1f9d61d74017d90e149728cb3d283e0a0e0Chris Lattner case 'e': 725f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar if (Name == "exp") 726508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson return ConstantFoldFP(exp, V, Ty, Context); 727c5f6a1f9d61d74017d90e149728cb3d283e0a0e0Chris Lattner break; 728c5f6a1f9d61d74017d90e149728cb3d283e0a0e0Chris Lattner case 'f': 729f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar if (Name == "fabs") 730508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson return ConstantFoldFP(fabs, V, Ty, Context); 731f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar else if (Name == "floor") 732508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson return ConstantFoldFP(floor, V, Ty, Context); 733c5f6a1f9d61d74017d90e149728cb3d283e0a0e0Chris Lattner break; 734c5f6a1f9d61d74017d90e149728cb3d283e0a0e0Chris Lattner case 'l': 735f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar if (Name == "log" && V > 0) 736508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson return ConstantFoldFP(log, V, Ty, Context); 737f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar else if (Name == "log10" && V > 0) 738508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson return ConstantFoldFP(log10, V, Ty, Context); 739f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar else if (Name == "llvm.sqrt.f32" || 740f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar Name == "llvm.sqrt.f64") { 741c5f6a1f9d61d74017d90e149728cb3d283e0a0e0Chris Lattner if (V >= -0.0) 742508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson return ConstantFoldFP(sqrt, V, Ty, Context); 743c5f6a1f9d61d74017d90e149728cb3d283e0a0e0Chris Lattner else // Undefined 744e922c0201916e0b980ab3cfe91e1413e68d55647Owen Anderson return Context.getNullValue(Ty); 745c5f6a1f9d61d74017d90e149728cb3d283e0a0e0Chris Lattner } 746c5f6a1f9d61d74017d90e149728cb3d283e0a0e0Chris Lattner break; 747c5f6a1f9d61d74017d90e149728cb3d283e0a0e0Chris Lattner case 's': 748f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar if (Name == "sin") 749508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson return ConstantFoldFP(sin, V, Ty, Context); 750f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar else if (Name == "sinh") 751508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson return ConstantFoldFP(sinh, V, Ty, Context); 752f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar else if (Name == "sqrt" && V >= 0) 753508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson return ConstantFoldFP(sqrt, V, Ty, Context); 754f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar else if (Name == "sqrtf" && V >= 0) 755508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson return ConstantFoldFP(sqrt, V, Ty, Context); 756f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar else if (Name == "sinf") 757508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson return ConstantFoldFP(sin, V, Ty, Context); 758c5f6a1f9d61d74017d90e149728cb3d283e0a0e0Chris Lattner break; 759c5f6a1f9d61d74017d90e149728cb3d283e0a0e0Chris Lattner case 't': 760f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar if (Name == "tan") 761508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson return ConstantFoldFP(tan, V, Ty, Context); 762f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar else if (Name == "tanh") 763508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson return ConstantFoldFP(tanh, V, Ty, Context); 764c5f6a1f9d61d74017d90e149728cb3d283e0a0e0Chris Lattner break; 765c5f6a1f9d61d74017d90e149728cb3d283e0a0e0Chris Lattner default: 766c5f6a1f9d61d74017d90e149728cb3d283e0a0e0Chris Lattner break; 767bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell } 768b83eb6447ba155342598f0fabe1f08f5baa9164aReid Spencer } else if (ConstantInt *Op = dyn_cast<ConstantInt>(Operands[0])) { 769f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar if (Name.startswith("llvm.bswap")) 770eed707b1e6097aac2bb6b3d47271f6300ace7f2eOwen Anderson return ConstantInt::get(Context, Op->getValue().byteSwap()); 771f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar else if (Name.startswith("llvm.ctpop")) 772eed707b1e6097aac2bb6b3d47271f6300ace7f2eOwen Anderson return ConstantInt::get(Ty, Op->getValue().countPopulation()); 773f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar else if (Name.startswith("llvm.cttz")) 774eed707b1e6097aac2bb6b3d47271f6300ace7f2eOwen Anderson return ConstantInt::get(Ty, Op->getValue().countTrailingZeros()); 775f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar else if (Name.startswith("llvm.ctlz")) 776eed707b1e6097aac2bb6b3d47271f6300ace7f2eOwen Anderson return ConstantInt::get(Ty, Op->getValue().countLeadingZeros()); 777bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell } 77872d88ae5447a3929c97e88f4c806213847b5d988Chris Lattner } else if (NumOperands == 2) { 779bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell if (ConstantFP *Op1 = dyn_cast<ConstantFP>(Operands[0])) { 7809ab7fb3ba47442d521a5bed09a27a5e8e7a786edDale Johannesen if (Ty!=Type::FloatTy && Ty!=Type::DoubleTy) 7819ab7fb3ba47442d521a5bed09a27a5e8e7a786edDale Johannesen return 0; 78243421b3dd70af5b70e71816521f37502c397cc65Dale Johannesen double Op1V = Ty==Type::FloatTy ? 78343421b3dd70af5b70e71816521f37502c397cc65Dale Johannesen (double)Op1->getValueAPF().convertToFloat(): 78443421b3dd70af5b70e71816521f37502c397cc65Dale Johannesen Op1->getValueAPF().convertToDouble(); 785bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell if (ConstantFP *Op2 = dyn_cast<ConstantFP>(Operands[1])) { 78643421b3dd70af5b70e71816521f37502c397cc65Dale Johannesen double Op2V = Ty==Type::FloatTy ? 78743421b3dd70af5b70e71816521f37502c397cc65Dale Johannesen (double)Op2->getValueAPF().convertToFloat(): 78843421b3dd70af5b70e71816521f37502c397cc65Dale Johannesen Op2->getValueAPF().convertToDouble(); 789bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell 790f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar if (Name == "pow") { 791508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson return ConstantFoldBinaryFP(pow, Op1V, Op2V, Ty, Context); 792f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar } else if (Name == "fmod") { 793508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson return ConstantFoldBinaryFP(fmod, Op1V, Op2V, Ty, Context); 794f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar } else if (Name == "atan2") { 795508955156a25a9abc470a29e1760aa176d341cf9Owen Anderson return ConstantFoldBinaryFP(atan2, Op1V, Op2V, Ty, Context); 796b5282dcf4745be59046f440980a1c0f0a50c9c09Chris Lattner } 797b5282dcf4745be59046f440980a1c0f0a50c9c09Chris Lattner } else if (ConstantInt *Op2C = dyn_cast<ConstantInt>(Operands[1])) { 798f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar if (Name == "llvm.powi.f32") { 7996f83c9c6ef0e7f79825a0a8f22941815e4b684c7Owen Anderson return ConstantFP::get(Context, APFloat((float)std::pow((float)Op1V, 80002a260aa11a2e1b2c14335274d3c42ca3f3eabc0Chris Lattner (int)Op2C->getZExtValue()))); 801f0443c1eb44d737d9bd78962932fc80f74c6113cDaniel Dunbar } else if (Name == "llvm.powi.f64") { 8026f83c9c6ef0e7f79825a0a8f22941815e4b684c7Owen Anderson return ConstantFP::get(Context, APFloat((double)std::pow((double)Op1V, 80302a260aa11a2e1b2c14335274d3c42ca3f3eabc0Chris Lattner (int)Op2C->getZExtValue()))); 804b5282dcf4745be59046f440980a1c0f0a50c9c09Chris Lattner } 805bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell } 806bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell } 807bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell } 808bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell return 0; 809bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell} 810bd9d37026a5c17d9a51371a6a5446bf4761ee7d6John Criswell 811