vendor/llvm/llvm-r72732

1 files changed, 23 insertions, 0 deletions

diff --git a/test/Analysis/GlobalsModRef/purecse.ll b/test/Analysis/GlobalsModRef/purecse.ll
new file mode 100644
index 0000000000000..dc3f6adda1435
--- /dev/null
+++ b/test/Analysis/GlobalsModRef/purecse.ll
@@ -0,0 +1,23 @@
+; Test that pure functions are cse'd away
+; RUN: llvm-as < %s | opt -globalsmodref-aa -gvn -instcombine | \
+; RUN: llvm-dis | not grep sub
+
+define i32 @pure(i32 %X) {
+        %Y = add i32 %X, 1              ; <i32> [#uses=1]
+        ret i32 %Y
+}
+
+define i32 @test1(i32 %X) {
+        %A = call i32 @pure( i32 %X )           ; <i32> [#uses=1]
+        %B = call i32 @pure( i32 %X )           ; <i32> [#uses=1]
+        %C = sub i32 %A, %B             ; <i32> [#uses=1]
+        ret i32 %C
+}
+
+define i32 @test2(i32 %X, i32* %P) {
+        %A = call i32 @pure( i32 %X )           ; <i32> [#uses=1]
+        store i32 %X, i32* %P ;; Does not invalidate 'pure' call.
+        %B = call i32 @pure( i32 %X )           ; <i32> [#uses=1]
+        %C = sub i32 %A, %B             ; <i32> [#uses=1]
+        ret i32 %C
+}