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| author | Evan Cheng <evan.cheng@apple.com> | 2012-05-03 01:45:13 +0000 |
|---|---|---|
| committer | Evan Cheng <evan.cheng@apple.com> | 2012-05-03 01:45:13 +0000 |
| commit | d99d68bcee8ce91a18c397756c702363e030fd83 (patch) | |
| tree | 1b61e12685ff3f767c998a31444d09201f8cc828 /lib/Target/X86/Utils | |
| parent | f12f6dff9784805e8f89309787231c1ec53a8c6e (diff) | |
| download | external_llvm-d99d68bcee8ce91a18c397756c702363e030fd83.zip external_llvm-d99d68bcee8ce91a18c397756c702363e030fd83.tar.gz external_llvm-d99d68bcee8ce91a18c397756c702363e030fd83.tar.bz2 | |
Fix two-address pass's aggressive instruction commuting heuristics. It's meant
to catch cases like:
%reg1024<def> = MOV r1
%reg1025<def> = MOV r0
%reg1026<def> = ADD %reg1024, %reg1025
r0 = MOV %reg1026
By commuting ADD, it let coalescer eliminate all of the copies. However, there
was a bug in the heuristics where it ended up commuting the ADD in:
%reg1024<def> = MOV r0
%reg1025<def> = MOV 0
%reg1026<def> = ADD %reg1024, %reg1025
r0 = MOV %reg1026
That did no benefit but rather ensure the last MOV would not be coalesced.
rdar://11355268
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156048 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Target/X86/Utils')
0 files changed, 0 insertions, 0 deletions