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| author | Chris Lattner <sabre@nondot.org> | 2008-05-28 05:30:41 +0000 |
|---|---|---|
| committer | Chris Lattner <sabre@nondot.org> | 2008-05-28 05:30:41 +0000 |
| commit | 59b27d9b8f3ad05918afd4f0625ed99b3ae1caa4 (patch) | |
| tree | 972f570b46f92773f937cbd48c623bf3bcd70108 | |
| parent | d04567eb6d17d6893b5e644380bded8dbaa68a44 (diff) | |
| download | external_llvm-59b27d9b8f3ad05918afd4f0625ed99b3ae1caa4.zip external_llvm-59b27d9b8f3ad05918afd4f0625ed99b3ae1caa4.tar.gz external_llvm-59b27d9b8f3ad05918afd4f0625ed99b3ae1caa4.tar.bz2 | |
Implement PR2370: memmove(x,x,size) -> noop.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51636 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | lib/Transforms/Scalar/InstructionCombining.cpp | 4 | ||||
| -rw-r--r-- | test/Transforms/InstCombine/memmove.ll | 6 |
2 files changed, 10 insertions, 0 deletions
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index 2020415..8c2dc3e 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -9131,6 +9131,10 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) { CI.setOperand(0, Intrinsic::getDeclaration(M, MemCpyID)); Changed = true; } + + // memmove(x,x,size) -> noop. + if (MMI->getSource() == MMI->getDest()) + return EraseInstFromFunction(CI); } // If we can determine a pointer alignment that is bigger than currently diff --git a/test/Transforms/InstCombine/memmove.ll b/test/Transforms/InstCombine/memmove.ll index 2cb346f..09ec67d 100644 --- a/test/Transforms/InstCombine/memmove.ll +++ b/test/Transforms/InstCombine/memmove.ll @@ -34,3 +34,9 @@ define i32 @test3() { ret i32 0 } +; PR2370 +define void @test4(i8* %a) { + tail call void @llvm.memmove.i32( i8* %a, i8* %a, i32 100, i32 1 ) + ret void +} + |