Make sure that pure calls don't kill loads

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@12416 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/test/Analysis/LoadVN/call_pure_function.ll b/test/Analysis/LoadVN/call_pure_function.ll
new file mode 100644 (file)
index 0000000..c9de486
--- /dev/null
+++ b/test/Analysis/LoadVN/call_pure_function.ll
@@ -0,0 +1,13 @@
+; RUN: llvm-as < %s | opt -basicaa -load-vn -gcse -instcombine | llvm-dis | not grep sub
+declare int %strlen(sbyte*)
+declare void %use(int %X)
+
+sbyte %test(sbyte* %P, sbyte* %Q) {
+       %A = load sbyte* %Q
+       %X = call int %strlen(sbyte* %P)
+       %B = load sbyte* %Q                ;; CSE with A.
+       call void %use(int %X)             ;; make strlen not dead
+
+       %C = sub sbyte %A, %B
+       ret sbyte %C
+}