From a7dc71130ffb41195e2efac2221692875144c18f Mon Sep 17 00:00:00 2001
From: Simon Pilgrim <llvm-dev@redking.me.uk>
Date: Mon, 16 Aug 2021 12:57:05 +0100
Subject: [PATCH] [InstCombine] Add PR38021 nuw test case.

---
 llvm/test/Transforms/InstCombine/AddOverFlow.ll | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/llvm/test/Transforms/InstCombine/AddOverFlow.ll b/llvm/test/Transforms/InstCombine/AddOverFlow.ll
index 3b7baba..e34e516 100644
--- a/llvm/test/Transforms/InstCombine/AddOverFlow.ll
+++ b/llvm/test/Transforms/InstCombine/AddOverFlow.ll
@@ -264,3 +264,14 @@ define i16 @ripple_no_nsw6(i16 %x, i16 %y) {
   %c = add i16 %b, %a
   ret i16 %c
 }
+
+define i8 @PR38021(i8 %x) {
+; CHECK-LABEL: @PR38021(
+; CHECK-NEXT:    [[CLEAR_TOP_3_BITS:%.*]] = lshr i8 [[X:%.*]], 3
+; CHECK-NEXT:    [[ADD:%.*]] = add nuw nsw i8 [[CLEAR_TOP_3_BITS]], -63
+; CHECK-NEXT:    ret i8 [[ADD]]
+;
+  %clear_top_3_bits = lshr i8 %x, 3
+  %add = add i8 %clear_top_3_bits, 193 ; 0b11000001
+  ret i8 %add
+}
-- 
2.7.4