[llvm] [InstCombine] Preserve nneg in foldLogicCastConstant (PR #157865)

[Yingwei Zheng via llvm-commits]

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@@ -2047,3 +2047,69 @@ define i1 @or_truncs(i8 %x) {
   %or1 = or i1 %trunc1, %trunc2
   ret i1 %or1
 }
+
+define i32 @or_zext_constant(i8 %a) {
+; CHECK-LABEL: @or_zext_constant(
+; CHECK-NEXT:    [[TMP1:%.*]] = or i8 [[A:%.*]], 1
+; CHECK-NEXT:    [[AND:%.*]] = zext i8 [[TMP1]] to i32
+; CHECK-NEXT:    ret i32 [[AND]]
+;
+  %zext = zext i8 %a to i32
+  %or = or i32 %zext, 1
+  ret i32 %or
+}
+
+define i32 @or_zext_minus_constant(i8 %a) {
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dtcxzyw wrote:

It is identical to `or_zext_constant`.

https://github.com/llvm/llvm-project/pull/157865