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| author | Dan Gohman <gohman@apple.com> | 2010-04-23 01:55:05 +0000 |
|---|---|---|
| committer | Dan Gohman <gohman@apple.com> | 2010-04-23 01:55:05 +0000 |
| commit | fafb890ee204d60456d0780ff55a149fa082eaea (patch) | |
| tree | 3be1fcd844734fe3036a9393c946ceb1c76f4bce /lib/Analysis/README.txt | |
| parent | c6863989fc268ee0ff1469e4856e2e9404e67336 (diff) | |
| download | external_llvm-fafb890ee204d60456d0780ff55a149fa082eaea.zip external_llvm-fafb890ee204d60456d0780ff55a149fa082eaea.tar.gz external_llvm-fafb890ee204d60456d0780ff55a149fa082eaea.tar.bz2 | |
Fix LSR to tolerate cases where ScalarEvolution initially
misses an opportunity to fold add operands, but folds them
after LSR has separated them out. This fixes rdar://7886751.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@102157 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Analysis/README.txt')
| -rw-r--r-- | lib/Analysis/README.txt | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/lib/Analysis/README.txt b/lib/Analysis/README.txt index c401090..88ea9f1 100644 --- a/lib/Analysis/README.txt +++ b/lib/Analysis/README.txt @@ -16,3 +16,15 @@ In addition to being much more complicated, it involves i65 arithmetic, which is very inefficient when expanded into code. //===---------------------------------------------------------------------===// + +In test/CodeGen/X86/lsr-delayed-fold.ll, + +ScalarEvolution is forming this expression: + +((trunc i64 (-1 * %arg5) to i32) + (trunc i64 %arg5 to i32) + (-1 * (trunc i64 undef to i32))) + +This could be folded to + +(-1 * (trunc i64 undef to i32)) + +//===---------------------------------------------------------------------===// |