[Reassociate] Add test for PR28367.

llvm-svn: 279063

llvm/test/Transforms/Reassociate/pr28367.ll

@@ -0,0 +1,28 @@
+; RUN: opt < %s -reassociate -S
+
+; PR28367
+
+; Check to make sure this test does not assert or segfault.  If we get too
+; aggressive with retrying instructions it's possible to invalidate our
+; iterator.  See PR28367 for complete details.
+
+define void @fn1(i32 %a, i1 %c, i32* %ptr)  {
+entry:
+  br label %for.cond
+
+for.cond:
+  %d.0 = phi i32 [ 1, %entry ], [ 2, %for.body ]
+  br i1 %c, label %for.end, label %for.body
+
+for.body:
+  %sub1 = sub i32 %a, %d.0
+  %dead1 = add i32 %sub1, 1
+  %dead2 = mul i32 %dead1, 3
+  %dead3 = mul i32 %dead2, %sub1
+  %sub2 = sub nsw i32 0, %d.0
+  store i32 %sub2, i32* %ptr, align 4
+  br label %for.cond
+
+for.end:
+  ret void
+}