An alloca can be equal to an argument. It can't *alias* an alloca, but it could
be equal, since there's nothing preventing a caller from correctly predicting
the stack location of an alloca.
llvm-svn: 174119
diff --git a/llvm/test/Transforms/InstSimplify/compare.ll b/llvm/test/Transforms/InstSimplify/compare.ll
index 56627b9..a6d7a64 100644
--- a/llvm/test/Transforms/InstSimplify/compare.ll
+++ b/llvm/test/Transforms/InstSimplify/compare.ll
@@ -647,3 +647,16 @@
%Y = icmp eq i32* %X, null
ret i1 %Y
}
+
+; It's not valid to fold a comparison of an argument with an alloca, even though
+; that's tempting. An argument can't *alias* an alloca, however the aliasing rule
+; relies on restrictions against guessing an object's address and dereferencing.
+; There are no restrictions against guessing an object's address and comparing.
+
+define i1 @alloca_argument_compare(i64* %arg) {
+ %alloc = alloca i64
+ %cmp = icmp eq i64* %arg, %alloc
+ ret i1 %cmp
+ ; CHECK: alloca_argument_compare
+ ; CHECK: ret i1 %cmp
+}