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| author | Duncan Sands <baldrick@free.fr> | 2011-01-01 16:12:09 +0000 |
|---|---|---|
| committer | Duncan Sands <baldrick@free.fr> | 2011-01-01 16:12:09 +0000 |
| commit | 7cf85e74e3885005ca8e5fdb155fa5351e255b85 (patch) | |
| tree | a2849e3f74b4753e12d33981b7d3aa62256efdbf /lib/Target/README.txt | |
| parent | c88e91b875fc85ecc3e0d0f51b4a71dca9f29012 (diff) | |
| download | llvm-7cf85e74e3885005ca8e5fdb155fa5351e255b85.tar.gz llvm-7cf85e74e3885005ca8e5fdb155fa5351e255b85.tar.bz2 llvm-7cf85e74e3885005ca8e5fdb155fa5351e255b85.tar.xz | |
Fix a README item by having InstructionSimplify do a mild form of value
numbering, in which it considers (for example) "%a = add i32 %x, %y" and
"%b = add i32 %x, %y" to be equal because the operands are equal and the
result of the instructions only depends on the values of the operands.
This has almost no effect (it removes 4 instructions from gcc-as-one-file),
and perhaps slows down compilation: I measured a 0.4% slowdown on the large
gcc-as-one-file testcase, but it wasn't statistically significant.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122654 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Target/README.txt')
| -rw-r--r-- | lib/Target/README.txt | 11 |
1 files changed, 0 insertions, 11 deletions
diff --git a/lib/Target/README.txt b/lib/Target/README.txt index ec5c412765..c9561660b1 100644 --- a/lib/Target/README.txt +++ b/lib/Target/README.txt @@ -2065,14 +2065,3 @@ entry: } //===---------------------------------------------------------------------===// - -This compare could fold to false: - -define i1 @g(i32 a) nounwind readnone { - %add = shl i32 %a, 1 - %mul = shl i32 %a, 1 - %cmp = icmp ugt i32 %add, %mul - ret i1 %cmp -} - -//===---------------------------------------------------------------------===// |