diff options
| -rw-r--r-- | lib/Transforms/Scalar/SimplifyLibCalls.cpp | 2 | ||||
| -rw-r--r-- | test/Transforms/SimplifyLibCalls/2009-05-30-memcmp-byte.ll | 14 |
2 files changed, 15 insertions, 1 deletions
diff --git a/lib/Transforms/Scalar/SimplifyLibCalls.cpp b/lib/Transforms/Scalar/SimplifyLibCalls.cpp index 8c41c728c0..4b0064090c 100644 --- a/lib/Transforms/Scalar/SimplifyLibCalls.cpp +++ b/lib/Transforms/Scalar/SimplifyLibCalls.cpp @@ -878,7 +878,7 @@ struct VISIBILITY_HIDDEN MemCmpOpt : public LibCallOptimization { if (Len == 1) { // memcmp(S1,S2,1) -> *LHS - *RHS Value *LHSV = B.CreateLoad(CastToCStr(LHS, B), "lhsv"); Value *RHSV = B.CreateLoad(CastToCStr(RHS, B), "rhsv"); - return B.CreateZExt(B.CreateSub(LHSV, RHSV, "chardiff"), CI->getType()); + return B.CreateSExt(B.CreateSub(LHSV, RHSV, "chardiff"), CI->getType()); } // memcmp(S1,S2,2) != 0 -> (*(short*)LHS ^ *(short*)RHS) != 0 diff --git a/test/Transforms/SimplifyLibCalls/2009-05-30-memcmp-byte.ll b/test/Transforms/SimplifyLibCalls/2009-05-30-memcmp-byte.ll new file mode 100644 index 0000000000..f7209934f7 --- /dev/null +++ b/test/Transforms/SimplifyLibCalls/2009-05-30-memcmp-byte.ll @@ -0,0 +1,14 @@ +; RUN: llvm-as < %s | opt -simplify-libcalls -instcombine | llvm-dis | grep {ret i32 -65} +; PR4284 + +define i32 @test() nounwind { +entry: + %c0 = alloca i8, align 1 ; <i8*> [#uses=2] + %c2 = alloca i8, align 1 ; <i8*> [#uses=2] + store i8 64, i8* %c0 + store i8 -127, i8* %c2 + %call = call i32 @memcmp(i8* %c0, i8* %c2, i32 1) ; <i32> [#uses=1] + ret i32 %call +} + +declare i32 @memcmp(i8*, i8*, i32) |