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Make the MemCpyOptimizer a bit more aggressive. I can't think of a scenerio

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where this would be bad as the backend shouldn't have a problem inlining small
memcpys.
rdar://10510150

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145865 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chad Rosier 2011-12-05 22:37:00 +00:00
parent 713c70238c
commit d8bd26ee24
2 changed files with 18 additions and 2 deletions
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2
lib/Transforms/Scalar/MemCpyOptimizer.cpp
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@ -148,7 +148,7 @@ struct MemsetRange {
bool MemsetRange::isProfitableToUseMemset(const TargetData &TD) const {
// If we found more than 8 stores to merge or 64 bytes, use memset.
if (TheStores.size() >= 8 || End-Start >= 64) return true;
if (TheStores.size() >= 4 || End-Start >= 16) return true;
// If there is nothing to merge, don't do anything.
if (TheStores.size() < 2) return false;

18
test/Transforms/MemCpyOpt/form-memset.ll
View File

@ -57,8 +57,8 @@ entry:
declare i32 @bar(...)
%struct.MV = type { i16, i16 }
%struct.MV = type { i16, i16 }
define void @test2() nounwind {
entry:
@ -220,3 +220,19 @@ entry:
; CHECK: call void @llvm.memset.p0i8.i64(i8* %2, i8 0, i64 24, i32 1, i1 false)
}
; More aggressive heuristic
; rdar://9892684
define void @test7(i32* nocapture %c) nounwind optsize {
store i32 -1, i32* %c, align 4
%1 = getelementptr inbounds i32* %c, i32 1
store i32 -1, i32* %1, align 4
%2 = getelementptr inbounds i32* %c, i32 2
store i32 -1, i32* %2, align 4
%3 = getelementptr inbounds i32* %c, i32 3
store i32 -1, i32* %3, align 4
%4 = getelementptr inbounds i32* %c, i32 4
store i32 -1, i32* %4, align 4
; CHECK: @test7
; CHECK: call void @llvm.memset.p0i8.i64(i8* %5, i8 -1, i64 20, i32 4, i1 false)
ret void
}