Reduce x - y to -y when we know the 'x' part will get masked off anyways.

llvm-svn: 53271

1 files changed, 9 insertions, 0 deletions

diff --git a/llvm/test/Transforms/InstCombine/2008-07-08-SubAnd.ll b/llvm/test/Transforms/InstCombine/2008-07-08-SubAnd.ll
new file mode 100644
index 00000000000..bf3afb9e3bb
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/2008-07-08-SubAnd.ll
@@ -0,0 +1,9 @@
+; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep -v {i32 8}
+; PR2330
+
+define i32 @a(i32 %a) nounwind  {
+entry:
+	%tmp2 = sub i32 8, %a		; <i32> [#uses=1]
+	%tmp3 = and i32 %tmp2, 7		; <i32> [#uses=1]
+	ret i32 %tmp3
+}