1Analysis Opportunities:
2
3//===---------------------------------------------------------------------===//
4
5In test/Transforms/LoopStrengthReduce/quadradic-exit-value.ll, the
6ScalarEvolution expression for %r is this:
7
8  {1,+,3,+,2}<loop>
9
10Outside the loop, this could be evaluated simply as (%n * %n), however
11ScalarEvolution currently evaluates it as
12
13  (-2 + (2 * (trunc i65 (((zext i64 (-2 + %n) to i65) * (zext i64 (-1 + %n) to i65)) /u 2) to i64)) + (3 * %n))
14
15In addition to being much more complicated, it involves i65 arithmetic,
16which is very inefficient when expanded into code.
17
18//===---------------------------------------------------------------------===//
19
20In formatValue in test/CodeGen/X86/lsr-delayed-fold.ll,
21
22ScalarEvolution is forming this expression:
23
24((trunc i64 (-1 * %arg5) to i32) + (trunc i64 %arg5 to i32) + (-1 * (trunc i64 undef to i32)))
25
26This could be folded to
27
28(-1 * (trunc i64 undef to i32))
29
30//===---------------------------------------------------------------------===//
31