From bf6214aab47b8c1153e56fa388a4ae898f0b9e51 Mon Sep 17 00:00:00 2001 From: Benjamin Kramer Date: Tue, 25 May 2010 22:53:43 +0000 Subject: Properly promote operands when optimizing a single-character memcmp. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@104648 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Scalar/SimplifyLibCalls.cpp | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'lib/Transforms') diff --git a/lib/Transforms/Scalar/SimplifyLibCalls.cpp b/lib/Transforms/Scalar/SimplifyLibCalls.cpp index b053cfc..0f3ab7d 100644 --- a/lib/Transforms/Scalar/SimplifyLibCalls.cpp +++ b/lib/Transforms/Scalar/SimplifyLibCalls.cpp @@ -558,9 +558,12 @@ struct MemCmpOpt : public LibCallOptimization { if (Len == 0) // memcmp(s1,s2,0) -> 0 return Constant::getNullValue(CI->getType()); - 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"); + // memcmp(S1,S2,1) -> *(unsigned char*)LHS - *(unsigned char*)RHS + if (Len == 1) { + Value *LHSV = B.CreateZExt(B.CreateLoad(CastToCStr(LHS, B), "lhsc"), + CI->getType(), "lhsv"); + Value *RHSV = B.CreateZExt(B.CreateLoad(CastToCStr(RHS, B), "rhsc"), + CI->getType(), "rhsv"); return B.CreateSExt(B.CreateSub(LHSV, RHSV, "chardiff"), CI->getType()); } -- cgit v1.1