[llvm-commits] [llvm] r72625 - in /llvm/trunk: lib/Transforms/Scalar/SimplifyLibCalls.cpp test/Transforms/SimplifyLibCalls/2009-05-30-memcmp-byte.ll

[Chris Lattner]

Author: lattner
Date: Sat May 30 13:43:04 2009
New Revision: 72625

URL: http://llvm.org/viewvc/llvm-project?rev=72625&view=rev
Log:
fix PR4284, a bug in simplifylibcalls handling memcmp.  Patch by 
Benjamin Kramer!

Added:
    llvm/trunk/test/Transforms/SimplifyLibCalls/2009-05-30-memcmp-byte.ll
Modified:
    llvm/trunk/lib/Transforms/Scalar/SimplifyLibCalls.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/SimplifyLibCalls.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/SimplifyLibCalls.cpp?rev=72625&r1=72624&r2=72625&view=diff

==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/SimplifyLibCalls.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/SimplifyLibCalls.cpp Sat May 30 13:43:04 2009
@@ -878,7 +878,7 @@
     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

Added: llvm/trunk/test/Transforms/SimplifyLibCalls/2009-05-30-memcmp-byte.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/SimplifyLibCalls/2009-05-30-memcmp-byte.ll?rev=72625&view=auto

==============================================================================
--- llvm/trunk/test/Transforms/SimplifyLibCalls/2009-05-30-memcmp-byte.ll (added)
+++ llvm/trunk/test/Transforms/SimplifyLibCalls/2009-05-30-memcmp-byte.ll Sat May 30 13:43:04 2009
@@ -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)