Don't attempt to add 'nsw' when intermediate instructions had no such guarantee.

llvm-svn: 137572

1 files changed, 29 insertions, 1 deletions

diff --git a/llvm/test/Transforms/InstCombine/nsw.ll b/llvm/test/Transforms/InstCombine/nsw.ll
index 698296384ae..0e715075fc3 100644
--- a/llvm/test/Transforms/InstCombine/nsw.ll
+++ b/llvm/test/Transforms/InstCombine/nsw.ll
@@ -46,10 +46,38 @@ define i32 @preserve1(i32 %x) nounwind {
   ret i32 %add3
 }
 
+; CHECK: @preserve2
+; CHECK: add nsw i8 %A, %B
+; CHECK: add nsw i8
+define i8 @preserve2(i8 %A, i8 %B) nounwind {
+  %x = add nsw i8 %A, 10
+  %y = add nsw i8 %B, 10
+  %add = add nsw i8 %x, %y
+  ret i8 %add
+}
+
 ; CHECK: @nopreserve1
 ; CHECK: add i8 %x, -126
 define i8 @nopreserve1(i8 %x) nounwind {
   %add = add nsw i8 %x, 127
   %add3 = add nsw i8 %add, 3
   ret i8 %add3
-}
\ No newline at end of file
+}
+
+; CHECK: @nopreserve2
+; CHECK: add i8 %x, 3
+define i8 @nopreserve2(i8 %x) nounwind {
+  %add = add i8 %x, 1
+  %add3 = add nsw i8 %add, 2
+  ret i8 %add3
+}
+
+; CHECK: @nopreserve3
+; CHECK: add i8 %A, %B
+; CHECK: add i8
+define i8 @nopreserve3(i8 %A, i8 %B) nounwind {
+  %x = add i8 %A, 10
+  %y = add i8 %B, 10
+  %add = add nsw i8 %x, %y
+  ret i8 %add
+}