Imported Upstream version 5.18.0.161

Former-commit-id: 4db48158d3a35497b8f118ab21b5f08ac3d86d98

external/llvm/test/Transforms/LoopSimplifyCFG/merge-header.ll

@@ -0,0 +1,35 @@
+; RUN: opt -S -loop-simplifycfg < %s | FileCheck %s
+; RUN: opt -S -passes='require<domtree>,loop(simplify-cfg)' < %s | FileCheck %s
+
+; CHECK-LABEL: foo
+; CHECK:      entry:
+; CHECK-NEXT:   br label %[[LOOP:[a-z]+]]
+; CHECK:      [[LOOP]]:
+; CHECK-NEXT:   phi
+; CHECK-NOT:    br label
+; CHECK:        br i1
+define i32 @foo(i32* %P, i64* %Q) {
+entry:
+  br label %outer
+
+outer:                                            ; preds = %outer.latch2, %entry
+  %y.2 = phi i32 [ 0, %entry ], [ %y.inc2, %outer.latch2 ]
+  br label %inner
+
+inner:                                            ; preds = %outer
+  store i32 0, i32* %P
+  store i32 1, i32* %P
+  store i32 2, i32* %P
+  %y.inc2 = add nsw i32 %y.2, 1
+  %exitcond.outer = icmp eq i32 %y.inc2, 3
+  store i32 %y.2, i32* %P
+  br i1 %exitcond.outer, label %exit, label %outer.latch2
+
+outer.latch2:                                     ; preds = %inner
+  %t = sext i32 %y.inc2 to i64
+  store i64 %t, i64* %Q
+  br label %outer
+
+exit:                                             ; preds = %inner
+  ret i32 0
+}