ScalarEvolutionExpander.cpp revision 2d1be87ee40a4a0241d94448173879d9df2bc5b3
136f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman//===- ScalarEvolutionExpander.cpp - Scalar Evolution Analysis --*- C++ -*-===// 236f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman// 336f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman// The LLVM Compiler Infrastructure 436f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman// 54ee451de366474b9c228b4e5fa573795a715216dChris Lattner// This file is distributed under the University of Illinois Open Source 64ee451de366474b9c228b4e5fa573795a715216dChris Lattner// License. See LICENSE.TXT for details. 736f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman// 836f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman//===----------------------------------------------------------------------===// 936f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman// 1036f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman// This file contains the implementation of the scalar evolution expander, 1136f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman// which is used to generate the code corresponding to a given scalar evolution 1236f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman// expression. 1336f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman// 1436f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman//===----------------------------------------------------------------------===// 1536f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman 1636f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman#include "llvm/Analysis/ScalarEvolutionExpander.h" 17e81561909d128c6e2d8033cb5465a49b2596b26aBill Wendling#include "llvm/Analysis/LoopInfo.h" 182d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman#include "llvm/Target/TargetData.h" 1936f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begemanusing namespace llvm; 2036f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman 21ca1a4bebb3928ba18fb8751e2f0c0f88fad54cfdChris Lattner/// InsertCastOfTo - Insert a cast of V to the specified type, doing what 22ca1a4bebb3928ba18fb8751e2f0c0f88fad54cfdChris Lattner/// we can to share the casts. 233ba68b9eef2851dae8a9d1b18928c6fa2e3c5f87Reid SpencerValue *SCEVExpander::InsertCastOfTo(Instruction::CastOps opcode, Value *V, 243ba68b9eef2851dae8a9d1b18928c6fa2e3c5f87Reid Spencer const Type *Ty) { 252d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman // Short-circuit unnecessary bitcasts. 262d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman if (opcode == Instruction::BitCast && V->getType() == Ty) 272d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman return V; 282d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman 29ca1a4bebb3928ba18fb8751e2f0c0f88fad54cfdChris Lattner // FIXME: keep track of the cast instruction. 30ca1a4bebb3928ba18fb8751e2f0c0f88fad54cfdChris Lattner if (Constant *C = dyn_cast<Constant>(V)) 31d977d8651a5cd26a3e1088267f31cade405f2adfReid Spencer return ConstantExpr::getCast(opcode, C, Ty); 32ca1a4bebb3928ba18fb8751e2f0c0f88fad54cfdChris Lattner 33ca1a4bebb3928ba18fb8751e2f0c0f88fad54cfdChris Lattner if (Argument *A = dyn_cast<Argument>(V)) { 34ca1a4bebb3928ba18fb8751e2f0c0f88fad54cfdChris Lattner // Check to see if there is already a cast! 35ca1a4bebb3928ba18fb8751e2f0c0f88fad54cfdChris Lattner for (Value::use_iterator UI = A->use_begin(), E = A->use_end(); 36ca1a4bebb3928ba18fb8751e2f0c0f88fad54cfdChris Lattner UI != E; ++UI) { 37ca1a4bebb3928ba18fb8751e2f0c0f88fad54cfdChris Lattner if ((*UI)->getType() == Ty) 383913187bf6135e6a71260c65eed664095c8f9ce9Wojciech Matyjewicz if (CastInst *CI = dyn_cast<CastInst>(cast<Instruction>(*UI))) 393913187bf6135e6a71260c65eed664095c8f9ce9Wojciech Matyjewicz if (CI->getOpcode() == opcode) { 403913187bf6135e6a71260c65eed664095c8f9ce9Wojciech Matyjewicz // If the cast isn't the first instruction of the function, move it. 413913187bf6135e6a71260c65eed664095c8f9ce9Wojciech Matyjewicz if (BasicBlock::iterator(CI) != 423913187bf6135e6a71260c65eed664095c8f9ce9Wojciech Matyjewicz A->getParent()->getEntryBlock().begin()) { 433913187bf6135e6a71260c65eed664095c8f9ce9Wojciech Matyjewicz CI->moveBefore(A->getParent()->getEntryBlock().begin()); 443913187bf6135e6a71260c65eed664095c8f9ce9Wojciech Matyjewicz } 453913187bf6135e6a71260c65eed664095c8f9ce9Wojciech Matyjewicz return CI; 46ca1a4bebb3928ba18fb8751e2f0c0f88fad54cfdChris Lattner } 47ca1a4bebb3928ba18fb8751e2f0c0f88fad54cfdChris Lattner } 487cbd8a3e92221437048b484d5ef9c0a22d0f8c58Gabor Greif return CastInst::Create(opcode, V, Ty, V->getName(), 49d977d8651a5cd26a3e1088267f31cade405f2adfReid Spencer A->getParent()->getEntryBlock().begin()); 50ca1a4bebb3928ba18fb8751e2f0c0f88fad54cfdChris Lattner } 513913187bf6135e6a71260c65eed664095c8f9ce9Wojciech Matyjewicz 52ca1a4bebb3928ba18fb8751e2f0c0f88fad54cfdChris Lattner Instruction *I = cast<Instruction>(V); 533913187bf6135e6a71260c65eed664095c8f9ce9Wojciech Matyjewicz 54ca1a4bebb3928ba18fb8751e2f0c0f88fad54cfdChris Lattner // Check to see if there is already a cast. If there is, use it. 55ca1a4bebb3928ba18fb8751e2f0c0f88fad54cfdChris Lattner for (Value::use_iterator UI = I->use_begin(), E = I->use_end(); 56ca1a4bebb3928ba18fb8751e2f0c0f88fad54cfdChris Lattner UI != E; ++UI) { 57ca1a4bebb3928ba18fb8751e2f0c0f88fad54cfdChris Lattner if ((*UI)->getType() == Ty) 583913187bf6135e6a71260c65eed664095c8f9ce9Wojciech Matyjewicz if (CastInst *CI = dyn_cast<CastInst>(cast<Instruction>(*UI))) 593913187bf6135e6a71260c65eed664095c8f9ce9Wojciech Matyjewicz if (CI->getOpcode() == opcode) { 603913187bf6135e6a71260c65eed664095c8f9ce9Wojciech Matyjewicz BasicBlock::iterator It = I; ++It; 613913187bf6135e6a71260c65eed664095c8f9ce9Wojciech Matyjewicz if (isa<InvokeInst>(I)) 623913187bf6135e6a71260c65eed664095c8f9ce9Wojciech Matyjewicz It = cast<InvokeInst>(I)->getNormalDest()->begin(); 633913187bf6135e6a71260c65eed664095c8f9ce9Wojciech Matyjewicz while (isa<PHINode>(It)) ++It; 643913187bf6135e6a71260c65eed664095c8f9ce9Wojciech Matyjewicz if (It != BasicBlock::iterator(CI)) { 653913187bf6135e6a71260c65eed664095c8f9ce9Wojciech Matyjewicz // Splice the cast immediately after the operand in question. 663913187bf6135e6a71260c65eed664095c8f9ce9Wojciech Matyjewicz CI->moveBefore(It); 673913187bf6135e6a71260c65eed664095c8f9ce9Wojciech Matyjewicz } 683913187bf6135e6a71260c65eed664095c8f9ce9Wojciech Matyjewicz return CI; 69ca1a4bebb3928ba18fb8751e2f0c0f88fad54cfdChris Lattner } 70ca1a4bebb3928ba18fb8751e2f0c0f88fad54cfdChris Lattner } 71ca1a4bebb3928ba18fb8751e2f0c0f88fad54cfdChris Lattner BasicBlock::iterator IP = I; ++IP; 72ca1a4bebb3928ba18fb8751e2f0c0f88fad54cfdChris Lattner if (InvokeInst *II = dyn_cast<InvokeInst>(I)) 73ca1a4bebb3928ba18fb8751e2f0c0f88fad54cfdChris Lattner IP = II->getNormalDest()->begin(); 74ca1a4bebb3928ba18fb8751e2f0c0f88fad54cfdChris Lattner while (isa<PHINode>(IP)) ++IP; 757cbd8a3e92221437048b484d5ef9c0a22d0f8c58Gabor Greif return CastInst::Create(opcode, V, Ty, V->getName(), IP); 76ca1a4bebb3928ba18fb8751e2f0c0f88fad54cfdChris Lattner} 77ca1a4bebb3928ba18fb8751e2f0c0f88fad54cfdChris Lattner 787fec90ebf4ebe7aa73a6dd7d275c255587c041adChris Lattner/// InsertBinop - Insert the specified binary operator, doing a small amount 797fec90ebf4ebe7aa73a6dd7d275c255587c041adChris Lattner/// of work to avoid inserting an obviously redundant operation. 807fec90ebf4ebe7aa73a6dd7d275c255587c041adChris LattnerValue *SCEVExpander::InsertBinop(Instruction::BinaryOps Opcode, Value *LHS, 818a08769bad43a22fae2845bb0ba0fd1266cd55c8Wojciech Matyjewicz Value *RHS, Instruction *InsertPt) { 820f0eb18addc94bf3d8179fbce162c8c4622b9866Dan Gohman // Fold a binop with constant operands. 830f0eb18addc94bf3d8179fbce162c8c4622b9866Dan Gohman if (Constant *CLHS = dyn_cast<Constant>(LHS)) 840f0eb18addc94bf3d8179fbce162c8c4622b9866Dan Gohman if (Constant *CRHS = dyn_cast<Constant>(RHS)) 850f0eb18addc94bf3d8179fbce162c8c4622b9866Dan Gohman return ConstantExpr::get(Opcode, CLHS, CRHS); 860f0eb18addc94bf3d8179fbce162c8c4622b9866Dan Gohman 877fec90ebf4ebe7aa73a6dd7d275c255587c041adChris Lattner // Do a quick scan to see if we have this binop nearby. If so, reuse it. 887fec90ebf4ebe7aa73a6dd7d275c255587c041adChris Lattner unsigned ScanLimit = 6; 898a08769bad43a22fae2845bb0ba0fd1266cd55c8Wojciech Matyjewicz BasicBlock::iterator BlockBegin = InsertPt->getParent()->begin(); 908a08769bad43a22fae2845bb0ba0fd1266cd55c8Wojciech Matyjewicz if (InsertPt != BlockBegin) { 918a08769bad43a22fae2845bb0ba0fd1266cd55c8Wojciech Matyjewicz // Scanning starts from the last instruction before InsertPt. 928a08769bad43a22fae2845bb0ba0fd1266cd55c8Wojciech Matyjewicz BasicBlock::iterator IP = InsertPt; 938a08769bad43a22fae2845bb0ba0fd1266cd55c8Wojciech Matyjewicz --IP; 948a08769bad43a22fae2845bb0ba0fd1266cd55c8Wojciech Matyjewicz for (; ScanLimit; --IP, --ScanLimit) { 958a08769bad43a22fae2845bb0ba0fd1266cd55c8Wojciech Matyjewicz if (BinaryOperator *BinOp = dyn_cast<BinaryOperator>(IP)) 968a08769bad43a22fae2845bb0ba0fd1266cd55c8Wojciech Matyjewicz if (BinOp->getOpcode() == Opcode && BinOp->getOperand(0) == LHS && 978a08769bad43a22fae2845bb0ba0fd1266cd55c8Wojciech Matyjewicz BinOp->getOperand(1) == RHS) 988a08769bad43a22fae2845bb0ba0fd1266cd55c8Wojciech Matyjewicz return BinOp; 998a08769bad43a22fae2845bb0ba0fd1266cd55c8Wojciech Matyjewicz if (IP == BlockBegin) break; 1008a08769bad43a22fae2845bb0ba0fd1266cd55c8Wojciech Matyjewicz } 1017fec90ebf4ebe7aa73a6dd7d275c255587c041adChris Lattner } 1028a08769bad43a22fae2845bb0ba0fd1266cd55c8Wojciech Matyjewicz 1038a08769bad43a22fae2845bb0ba0fd1266cd55c8Wojciech Matyjewicz // If we haven't found this binop, insert it. 1047cbd8a3e92221437048b484d5ef9c0a22d0f8c58Gabor Greif return BinaryOperator::Create(Opcode, LHS, RHS, "tmp", InsertPt); 1057fec90ebf4ebe7aa73a6dd7d275c255587c041adChris Lattner} 1067fec90ebf4ebe7aa73a6dd7d275c255587c041adChris Lattner 107e24fa64d52330626553298f56ba5aa702624c282Dan GohmanValue *SCEVExpander::visitAddExpr(SCEVAddExpr *S) { 1082d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman const Type *Ty = S->getType(); 1092d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman if (isa<PointerType>(Ty)) Ty = TD.getIntPtrType(); 110e24fa64d52330626553298f56ba5aa702624c282Dan Gohman Value *V = expand(S->getOperand(S->getNumOperands()-1)); 1112d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman V = InsertCastOfTo(CastInst::getCastOpcode(V, false, Ty, false), V, Ty); 112e24fa64d52330626553298f56ba5aa702624c282Dan Gohman 113e24fa64d52330626553298f56ba5aa702624c282Dan Gohman // Emit a bunch of add instructions 1142d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman for (int i = S->getNumOperands()-2; i >= 0; --i) { 1152d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman Value *W = expand(S->getOperand(i)); 1162d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman W = InsertCastOfTo(CastInst::getCastOpcode(W, false, Ty, false), W, Ty); 1172d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman V = InsertBinop(Instruction::Add, V, W, InsertPt); 1182d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman } 119e24fa64d52330626553298f56ba5aa702624c282Dan Gohman return V; 120e24fa64d52330626553298f56ba5aa702624c282Dan Gohman} 121e24fa64d52330626553298f56ba5aa702624c282Dan Gohman 12236f891bdf6cf38fcc655a0930ca18664e18518d4Nate BegemanValue *SCEVExpander::visitMulExpr(SCEVMulExpr *S) { 1232d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman const Type *Ty = S->getType(); 1242d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman if (isa<PointerType>(Ty)) Ty = TD.getIntPtrType(); 12536f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman int FirstOp = 0; // Set if we should emit a subtract. 12636f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman if (SCEVConstant *SC = dyn_cast<SCEVConstant>(S->getOperand(0))) 12736f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman if (SC->getValue()->isAllOnesValue()) 12836f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman FirstOp = 1; 12936f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman 13036f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman int i = S->getNumOperands()-2; 131d19534add90a2a894af61523b830887097bb780bDan Gohman Value *V = expand(S->getOperand(i+1)); 1322d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman V = InsertCastOfTo(CastInst::getCastOpcode(V, false, Ty, false), V, Ty); 13336f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman 13436f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman // Emit a bunch of multiply instructions 1352d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman for (; i >= FirstOp; --i) { 1362d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman Value *W = expand(S->getOperand(i)); 1372d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman W = InsertCastOfTo(CastInst::getCastOpcode(W, false, Ty, false), W, Ty); 1382d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman V = InsertBinop(Instruction::Mul, V, W, InsertPt); 1392d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman } 1402d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman 14136f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman // -1 * ... ---> 0 - ... 14236f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman if (FirstOp == 1) 1432d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman V = InsertBinop(Instruction::Sub, Constant::getNullValue(Ty), V, InsertPt); 14436f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman return V; 14536f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman} 14636f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman 1476177fd4fcee4d82692c47e33754ffe285c38cc69Nick LewyckyValue *SCEVExpander::visitUDivExpr(SCEVUDivExpr *S) { 1482d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman const Type *Ty = S->getType(); 1492d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman if (isa<PointerType>(Ty)) Ty = TD.getIntPtrType(); 1502d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman 1516177fd4fcee4d82692c47e33754ffe285c38cc69Nick Lewycky Value *LHS = expand(S->getLHS()); 1522d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman LHS = InsertCastOfTo(CastInst::getCastOpcode(LHS, false, Ty, false), LHS, Ty); 1536177fd4fcee4d82692c47e33754ffe285c38cc69Nick Lewycky if (SCEVConstant *SC = dyn_cast<SCEVConstant>(S->getRHS())) { 1546177fd4fcee4d82692c47e33754ffe285c38cc69Nick Lewycky const APInt &RHS = SC->getValue()->getValue(); 1556177fd4fcee4d82692c47e33754ffe285c38cc69Nick Lewycky if (RHS.isPowerOf2()) 1566177fd4fcee4d82692c47e33754ffe285c38cc69Nick Lewycky return InsertBinop(Instruction::LShr, LHS, 1572d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman ConstantInt::get(Ty, RHS.logBase2()), 1586177fd4fcee4d82692c47e33754ffe285c38cc69Nick Lewycky InsertPt); 1596177fd4fcee4d82692c47e33754ffe285c38cc69Nick Lewycky } 1606177fd4fcee4d82692c47e33754ffe285c38cc69Nick Lewycky 1616177fd4fcee4d82692c47e33754ffe285c38cc69Nick Lewycky Value *RHS = expand(S->getRHS()); 1622d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman RHS = InsertCastOfTo(CastInst::getCastOpcode(RHS, false, Ty, false), RHS, Ty); 1636177fd4fcee4d82692c47e33754ffe285c38cc69Nick Lewycky return InsertBinop(Instruction::UDiv, LHS, RHS, InsertPt); 1646177fd4fcee4d82692c47e33754ffe285c38cc69Nick Lewycky} 1656177fd4fcee4d82692c47e33754ffe285c38cc69Nick Lewycky 16636f891bdf6cf38fcc655a0930ca18664e18518d4Nate BegemanValue *SCEVExpander::visitAddRecExpr(SCEVAddRecExpr *S) { 16736f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman const Type *Ty = S->getType(); 16836f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman const Loop *L = S->getLoop(); 16936f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman // We cannot yet do fp recurrences, e.g. the xform of {X,+,F} --> X+{0,+,F} 1702d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman assert((Ty->isInteger() || isa<PointerType>(Ty)) && 1712d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman "Cannot expand fp recurrences yet!"); 17236f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman 17336f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman // {X,+,F} --> X + {0,+,F} 174cfeb6a450632f2a6cd05302633c8c2b8c90cfdfdDan Gohman if (!S->getStart()->isZero()) { 175d19534add90a2a894af61523b830887097bb780bDan Gohman Value *Start = expand(S->getStart()); 1762d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman if (isa<PointerType>(Start->getType())) 1772d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman Start = InsertCastOfTo(Instruction::PtrToInt, Start, TD.getIntPtrType()); 17836f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman std::vector<SCEVHandle> NewOps(S->op_begin(), S->op_end()); 179246b2564d3bbbafe06ebf6a67745cd24141b5cb4Dan Gohman NewOps[0] = SE.getIntegerSCEV(0, Ty); 180246b2564d3bbbafe06ebf6a67745cd24141b5cb4Dan Gohman Value *Rest = expand(SE.getAddRecExpr(NewOps, L)); 1812d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman if (isa<PointerType>(Rest->getType())) 1822d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman Rest = InsertCastOfTo(Instruction::PtrToInt, Rest, TD.getIntPtrType()); 18336f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman 18436f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman // FIXME: look for an existing add to use. 1857fec90ebf4ebe7aa73a6dd7d275c255587c041adChris Lattner return InsertBinop(Instruction::Add, Rest, Start, InsertPt); 18636f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman } 18736f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman 18836f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman // {0,+,1} --> Insert a canonical induction variable into the loop! 18917f1972c770dc18f5c7c3c95776b4d62ae9e121dDan Gohman if (S->isAffine() && 190246b2564d3bbbafe06ebf6a67745cd24141b5cb4Dan Gohman S->getOperand(1) == SE.getIntegerSCEV(1, Ty)) { 19136f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman // Create and insert the PHI node for the induction variable in the 19236f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman // specified loop. 19336f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman BasicBlock *Header = L->getHeader(); 194051a950000e21935165db56695e35bade668193bGabor Greif PHINode *PN = PHINode::Create(Ty, "indvar", Header->begin()); 19536f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman PN->addIncoming(Constant::getNullValue(Ty), L->getLoopPreheader()); 19636f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman 19736f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman pred_iterator HPI = pred_begin(Header); 19836f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman assert(HPI != pred_end(Header) && "Loop with zero preds???"); 19936f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman if (!L->contains(*HPI)) ++HPI; 20036f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman assert(HPI != pred_end(Header) && L->contains(*HPI) && 20136f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman "No backedge in loop?"); 20236f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman 20336f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman // Insert a unit add instruction right before the terminator corresponding 20436f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman // to the back-edge. 20524d6da5fedcf39891f7d8c5b031c01324b3db545Reid Spencer Constant *One = ConstantInt::get(Ty, 1); 2067cbd8a3e92221437048b484d5ef9c0a22d0f8c58Gabor Greif Instruction *Add = BinaryOperator::CreateAdd(PN, One, "indvar.next", 20736f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman (*HPI)->getTerminator()); 20836f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman 20936f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman pred_iterator PI = pred_begin(Header); 21036f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman if (*PI == L->getLoopPreheader()) 21136f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman ++PI; 21236f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman PN->addIncoming(Add, *PI); 21336f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman return PN; 21436f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman } 21536f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman 21636f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman // Get the canonical induction variable I for this loop. 21736f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman Value *I = getOrInsertCanonicalInductionVariable(L, Ty); 21836f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman 219df14a04b5ccbbe6a46c2ccb93e27b12a36ff163eChris Lattner // If this is a simple linear addrec, emit it now as a special case. 22017f1972c770dc18f5c7c3c95776b4d62ae9e121dDan Gohman if (S->isAffine()) { // {0,+,F} --> i*F 221d19534add90a2a894af61523b830887097bb780bDan Gohman Value *F = expand(S->getOperand(1)); 222df14a04b5ccbbe6a46c2ccb93e27b12a36ff163eChris Lattner 223df14a04b5ccbbe6a46c2ccb93e27b12a36ff163eChris Lattner // IF the step is by one, just return the inserted IV. 2246b6b6ef1677fa71b1072c2911b4c1f9524a558c9Zhou Sheng if (ConstantInt *CI = dyn_cast<ConstantInt>(F)) 2254d050d73210d15d8a86ee5967c417ddb5bee4543Reid Spencer if (CI->getValue() == 1) 226df14a04b5ccbbe6a46c2ccb93e27b12a36ff163eChris Lattner return I; 227df14a04b5ccbbe6a46c2ccb93e27b12a36ff163eChris Lattner 228df14a04b5ccbbe6a46c2ccb93e27b12a36ff163eChris Lattner // If the insert point is directly inside of the loop, emit the multiply at 229df14a04b5ccbbe6a46c2ccb93e27b12a36ff163eChris Lattner // the insert point. Otherwise, L is a loop that is a parent of the insert 230df14a04b5ccbbe6a46c2ccb93e27b12a36ff163eChris Lattner // point loop. If we can, move the multiply to the outer most loop that it 231df14a04b5ccbbe6a46c2ccb93e27b12a36ff163eChris Lattner // is safe to be in. 232df14a04b5ccbbe6a46c2ccb93e27b12a36ff163eChris Lattner Instruction *MulInsertPt = InsertPt; 233df14a04b5ccbbe6a46c2ccb93e27b12a36ff163eChris Lattner Loop *InsertPtLoop = LI.getLoopFor(MulInsertPt->getParent()); 234df14a04b5ccbbe6a46c2ccb93e27b12a36ff163eChris Lattner if (InsertPtLoop != L && InsertPtLoop && 235df14a04b5ccbbe6a46c2ccb93e27b12a36ff163eChris Lattner L->contains(InsertPtLoop->getHeader())) { 2365d2bc857ec1ae11ec2ea85e596f3712d02fd2c2bWojciech Matyjewicz do { 237df14a04b5ccbbe6a46c2ccb93e27b12a36ff163eChris Lattner // If we cannot hoist the multiply out of this loop, don't. 238df14a04b5ccbbe6a46c2ccb93e27b12a36ff163eChris Lattner if (!InsertPtLoop->isLoopInvariant(F)) break; 239df14a04b5ccbbe6a46c2ccb93e27b12a36ff163eChris Lattner 2405d2bc857ec1ae11ec2ea85e596f3712d02fd2c2bWojciech Matyjewicz BasicBlock *InsertPtLoopPH = InsertPtLoop->getLoopPreheader(); 2415d2bc857ec1ae11ec2ea85e596f3712d02fd2c2bWojciech Matyjewicz 2425d2bc857ec1ae11ec2ea85e596f3712d02fd2c2bWojciech Matyjewicz // If this loop hasn't got a preheader, we aren't able to hoist the 2435d2bc857ec1ae11ec2ea85e596f3712d02fd2c2bWojciech Matyjewicz // multiply. 2445d2bc857ec1ae11ec2ea85e596f3712d02fd2c2bWojciech Matyjewicz if (!InsertPtLoopPH) 2455d2bc857ec1ae11ec2ea85e596f3712d02fd2c2bWojciech Matyjewicz break; 2465d2bc857ec1ae11ec2ea85e596f3712d02fd2c2bWojciech Matyjewicz 2475d2bc857ec1ae11ec2ea85e596f3712d02fd2c2bWojciech Matyjewicz // Otherwise, move the insert point to the preheader. 2485d2bc857ec1ae11ec2ea85e596f3712d02fd2c2bWojciech Matyjewicz MulInsertPt = InsertPtLoopPH->getTerminator(); 249df14a04b5ccbbe6a46c2ccb93e27b12a36ff163eChris Lattner InsertPtLoop = InsertPtLoop->getParentLoop(); 2505d2bc857ec1ae11ec2ea85e596f3712d02fd2c2bWojciech Matyjewicz } while (InsertPtLoop != L); 251df14a04b5ccbbe6a46c2ccb93e27b12a36ff163eChris Lattner } 252df14a04b5ccbbe6a46c2ccb93e27b12a36ff163eChris Lattner 2537fec90ebf4ebe7aa73a6dd7d275c255587c041adChris Lattner return InsertBinop(Instruction::Mul, I, F, MulInsertPt); 25436f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman } 25536f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman 25636f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman // If this is a chain of recurrences, turn it into a closed form, using the 25736f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman // folders, then expandCodeFor the closed form. This allows the folders to 25836f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman // simplify the expression without having to build a bunch of special code 25936f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman // into this folder. 260246b2564d3bbbafe06ebf6a67745cd24141b5cb4Dan Gohman SCEVHandle IH = SE.getUnknown(I); // Get I as a "symbolic" SCEV. 26136f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman 262246b2564d3bbbafe06ebf6a67745cd24141b5cb4Dan Gohman SCEVHandle V = S->evaluateAtIteration(IH, SE); 263e81561909d128c6e2d8033cb5465a49b2596b26aBill Wendling //cerr << "Evaluated: " << *this << "\n to: " << *V << "\n"; 26436f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman 265d19534add90a2a894af61523b830887097bb780bDan Gohman return expand(V); 26636f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman} 26796fea337d27357e9b62abbf3d2d5ce29f1c8e870Anton Korobeynikov 26811f6d3b478c4fa09d126833c57fbac1d795ead31Dan GohmanValue *SCEVExpander::visitTruncateExpr(SCEVTruncateExpr *S) { 26911f6d3b478c4fa09d126833c57fbac1d795ead31Dan Gohman Value *V = expand(S->getOperand()); 2702d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman if (isa<PointerType>(V->getType())) 2712d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman V = InsertCastOfTo(Instruction::PtrToInt, V, TD.getIntPtrType()); 272e9324f360590793576d15d9e15c21a4c19ef8d1cGabor Greif return CastInst::CreateTruncOrBitCast(V, S->getType(), "tmp.", InsertPt); 27311f6d3b478c4fa09d126833c57fbac1d795ead31Dan Gohman} 27411f6d3b478c4fa09d126833c57fbac1d795ead31Dan Gohman 27511f6d3b478c4fa09d126833c57fbac1d795ead31Dan GohmanValue *SCEVExpander::visitZeroExtendExpr(SCEVZeroExtendExpr *S) { 27611f6d3b478c4fa09d126833c57fbac1d795ead31Dan Gohman Value *V = expand(S->getOperand()); 2772d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman if (isa<PointerType>(V->getType())) 2782d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman V = InsertCastOfTo(Instruction::PtrToInt, V, TD.getIntPtrType()); 279e9324f360590793576d15d9e15c21a4c19ef8d1cGabor Greif return CastInst::CreateZExtOrBitCast(V, S->getType(), "tmp.", InsertPt); 28011f6d3b478c4fa09d126833c57fbac1d795ead31Dan Gohman} 28111f6d3b478c4fa09d126833c57fbac1d795ead31Dan Gohman 28211f6d3b478c4fa09d126833c57fbac1d795ead31Dan GohmanValue *SCEVExpander::visitSignExtendExpr(SCEVSignExtendExpr *S) { 28311f6d3b478c4fa09d126833c57fbac1d795ead31Dan Gohman Value *V = expand(S->getOperand()); 2842d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman if (isa<PointerType>(V->getType())) 2852d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman V = InsertCastOfTo(Instruction::PtrToInt, V, TD.getIntPtrType()); 286e9324f360590793576d15d9e15c21a4c19ef8d1cGabor Greif return CastInst::CreateSExtOrBitCast(V, S->getType(), "tmp.", InsertPt); 28711f6d3b478c4fa09d126833c57fbac1d795ead31Dan Gohman} 28811f6d3b478c4fa09d126833c57fbac1d795ead31Dan Gohman 289c54c561c9f7270c055dd7ba75a3a003b771a42d9Nick LewyckyValue *SCEVExpander::visitSMaxExpr(SCEVSMaxExpr *S) { 290c54c561c9f7270c055dd7ba75a3a003b771a42d9Nick Lewycky Value *LHS = expand(S->getOperand(0)); 291c54c561c9f7270c055dd7ba75a3a003b771a42d9Nick Lewycky for (unsigned i = 1; i < S->getNumOperands(); ++i) { 292c54c561c9f7270c055dd7ba75a3a003b771a42d9Nick Lewycky Value *RHS = expand(S->getOperand(i)); 293c54c561c9f7270c055dd7ba75a3a003b771a42d9Nick Lewycky Value *ICmp = new ICmpInst(ICmpInst::ICMP_SGT, LHS, RHS, "tmp", InsertPt); 294051a950000e21935165db56695e35bade668193bGabor Greif LHS = SelectInst::Create(ICmp, LHS, RHS, "smax", InsertPt); 295c54c561c9f7270c055dd7ba75a3a003b771a42d9Nick Lewycky } 296c54c561c9f7270c055dd7ba75a3a003b771a42d9Nick Lewycky return LHS; 297c54c561c9f7270c055dd7ba75a3a003b771a42d9Nick Lewycky} 298c54c561c9f7270c055dd7ba75a3a003b771a42d9Nick Lewycky 2993e6307698084e7adfc10b739442ae29742beefd0Nick LewyckyValue *SCEVExpander::visitUMaxExpr(SCEVUMaxExpr *S) { 3003e6307698084e7adfc10b739442ae29742beefd0Nick Lewycky Value *LHS = expand(S->getOperand(0)); 3013e6307698084e7adfc10b739442ae29742beefd0Nick Lewycky for (unsigned i = 1; i < S->getNumOperands(); ++i) { 3023e6307698084e7adfc10b739442ae29742beefd0Nick Lewycky Value *RHS = expand(S->getOperand(i)); 3033e6307698084e7adfc10b739442ae29742beefd0Nick Lewycky Value *ICmp = new ICmpInst(ICmpInst::ICMP_UGT, LHS, RHS, "tmp", InsertPt); 304051a950000e21935165db56695e35bade668193bGabor Greif LHS = SelectInst::Create(ICmp, LHS, RHS, "umax", InsertPt); 3053e6307698084e7adfc10b739442ae29742beefd0Nick Lewycky } 3063e6307698084e7adfc10b739442ae29742beefd0Nick Lewycky return LHS; 3073e6307698084e7adfc10b739442ae29742beefd0Nick Lewycky} 3083e6307698084e7adfc10b739442ae29742beefd0Nick Lewycky 3092d1be87ee40a4a0241d94448173879d9df2bc5b3Dan GohmanValue *SCEVExpander::expandCodeFor(SCEVHandle SH, const Type *Ty, 3102d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman Instruction *IP) { 31111f6d3b478c4fa09d126833c57fbac1d795ead31Dan Gohman // Expand the code for this SCEV. 3122d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman assert(TD.getTypeSizeInBits(Ty) == TD.getTypeSizeInBits(SH->getType()) && 3132d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman "non-trivial casts should be done with the SCEVs directly!"); 31411f6d3b478c4fa09d126833c57fbac1d795ead31Dan Gohman this->InsertPt = IP; 3152d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman Value *V = expand(SH); 3162d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman return InsertCastOfTo(CastInst::getCastOpcode(V, false, Ty, false), V, Ty); 31711f6d3b478c4fa09d126833c57fbac1d795ead31Dan Gohman} 31811f6d3b478c4fa09d126833c57fbac1d795ead31Dan Gohman 31996fea337d27357e9b62abbf3d2d5ce29f1c8e870Anton KorobeynikovValue *SCEVExpander::expand(SCEV *S) { 32096fea337d27357e9b62abbf3d2d5ce29f1c8e870Anton Korobeynikov // Check to see if we already expanded this. 32196fea337d27357e9b62abbf3d2d5ce29f1c8e870Anton Korobeynikov std::map<SCEVHandle, Value*>::iterator I = InsertedExpressions.find(S); 32296fea337d27357e9b62abbf3d2d5ce29f1c8e870Anton Korobeynikov if (I != InsertedExpressions.end()) 32396fea337d27357e9b62abbf3d2d5ce29f1c8e870Anton Korobeynikov return I->second; 32496fea337d27357e9b62abbf3d2d5ce29f1c8e870Anton Korobeynikov 32596fea337d27357e9b62abbf3d2d5ce29f1c8e870Anton Korobeynikov Value *V = visit(S); 32696fea337d27357e9b62abbf3d2d5ce29f1c8e870Anton Korobeynikov InsertedExpressions[S] = V; 32796fea337d27357e9b62abbf3d2d5ce29f1c8e870Anton Korobeynikov return V; 32896fea337d27357e9b62abbf3d2d5ce29f1c8e870Anton Korobeynikov} 329