"There was a typo in my previous patch which leads to miscompilation of

strncat :(

strncat(foo, "bar", 99)
would be optimized to
memcpy(foo+strlen(foo), "bar", 100, 1)
instead of
memcpy(foo+strlen(foo), "bar", 4, 1)"

Patch by Benjamin Kramer!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@68905 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Scalar/SimplifyLibCalls.cpp b/lib/Transforms/Scalar/SimplifyLibCalls.cpp
index 7e23c95cded8a46f4fc9517fb5070bce377f4313..d53bc3f0cccd205260bfb8e0003b8f4e51f6fe15 100644 (file)
--- a/lib/Transforms/Scalar/SimplifyLibCalls.cpp
+++ b/lib/Transforms/Scalar/SimplifyLibCalls.cpp
@@ -582,7 +582,7 @@ struct VISIBILITY_HIDDEN StrNCatOpt : public StrCatOpt {
 
     // strncat(x, s, c) -> strcat(x, s)
     // s is constant so the strcat can be optimized further
-    EmitStrLenMemCpy(Src, Dst, Len, B);
+    EmitStrLenMemCpy(Src, Dst, SrcLen, B);
     return Dst;
   }
 };