--- /dev/null
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -S -simplifycfg < %s | FileCheck %s
+
+declare i8 @next_char();
+
+define void @test_no_msan() {
+; CHECK-LABEL: @test_no_msan(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: br label [[WHILE_BODY:%.*]]
+; CHECK: while.body:
+; CHECK-NEXT: br label [[WHILE_BODY_I:%.*]]
+; CHECK: while.body.i:
+; CHECK-NEXT: [[MAYBE_UNDEF:%.*]] = phi i1 [ undef, [[WHILE_BODY]] ], [ [[NEXT_MAYBE_UNDEF:%.*]], [[WHILE_BODY_I]] ]
+; CHECK-NEXT: [[C:%.*]] = call fastcc signext i8 @next_char()
+; CHECK-NEXT: [[C_10:%.*]] = icmp eq i8 [[C]], 10
+; CHECK-NEXT: [[C_13:%.*]] = icmp eq i8 [[C]], 13
+; CHECK-NEXT: [[C_10_OR_13:%.*]] = or i1 [[C_10]], [[C_13]]
+; CHECK-NEXT: [[NEXT_MAYBE_UNDEF]] = or i1 [[MAYBE_UNDEF]], [[C_10_OR_13]]
+; CHECK-NEXT: [[C_NOT_10_OR_13:%.*]] = xor i1 [[C_10_OR_13]], true
+; CHECK-NEXT: br i1 [[C_NOT_10_OR_13]], label [[WHILE_BODY_I]], label [[WHILE_BODY_I_BREAK:%.*]]
+; CHECK: while.body.i.break:
+; CHECK-NEXT: br i1 [[MAYBE_UNDEF]], label [[WHILE_BODY]], label [[SWITCH_EARLY_TEST:%.*]]
+; CHECK: switch.early.test:
+; CHECK-NEXT: switch i8 [[C]], label [[RETURN:%.*]] [
+; CHECK-NEXT: i8 13, label [[WHILE_BODY]]
+; CHECK-NEXT: i8 10, label [[WHILE_BODY]]
+; CHECK-NEXT: ]
+; CHECK: return:
+; CHECK-NEXT: ret void
+;
+
+entry:
+ br label %while.body
+
+while.body:
+ br label %while.body.i
+
+while.body.i:
+ %maybe_undef = phi i1 [ undef, %while.body ], [ %next_maybe_undef, %while.body.i ]
+ %c = call fastcc signext i8 @next_char()
+ %c_10 = icmp eq i8 %c, 10
+ %c_13 = icmp eq i8 %c, 13
+ %c_10_or_13 = or i1 %c_10, %c_13
+ %next_maybe_undef = or i1 %maybe_undef, %c_10_or_13
+ %c_not_10_or_13 = xor i1 %c_10_or_13, true
+ br i1 %c_not_10_or_13, label %while.body.i, label %while.body.i.break
+
+while.body.i.break:
+ ; NEXT_MAYBE_UNDEF is never undef if here
+ br i1 %next_maybe_undef, label %while.body, label %return
+
+
+return:
+ ret void
+}
+
+
+define void @test_msan() sanitize_memory {
+; CHECK-LABEL: @test_msan(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: br label [[WHILE_BODY:%.*]]
+; CHECK: while.body:
+; CHECK-NEXT: br label [[WHILE_BODY_I:%.*]]
+; CHECK: while.body.i:
+; CHECK-NEXT: [[MAYBE_UNDEF:%.*]] = phi i1 [ undef, [[WHILE_BODY]] ], [ [[NEXT_MAYBE_UNDEF:%.*]], [[WHILE_BODY_I]] ]
+; CHECK-NEXT: [[C:%.*]] = call fastcc signext i8 @next_char()
+; CHECK-NEXT: [[C_10:%.*]] = icmp eq i8 [[C]], 10
+; CHECK-NEXT: [[C_13:%.*]] = icmp eq i8 [[C]], 13
+; CHECK-NEXT: [[C_10_OR_13:%.*]] = or i1 [[C_10]], [[C_13]]
+; CHECK-NEXT: [[NEXT_MAYBE_UNDEF]] = or i1 [[MAYBE_UNDEF]], [[C_10_OR_13]]
+; CHECK-NEXT: [[C_NOT_10_OR_13:%.*]] = xor i1 [[C_10_OR_13]], true
+; CHECK-NEXT: br i1 [[C_NOT_10_OR_13]], label [[WHILE_BODY_I]], label [[WHILE_BODY_I_BREAK:%.*]]
+; CHECK: while.body.i.break:
+; CHECK-NEXT: br i1 [[NEXT_MAYBE_UNDEF]], label [[WHILE_BODY]], label [[RETURN:%.*]]
+; CHECK: return:
+; CHECK-NEXT: ret void
+;
+
+entry:
+ br label %while.body
+
+while.body:
+ br label %while.body.i
+
+while.body.i:
+ %maybe_undef = phi i1 [ undef, %while.body ], [ %next_maybe_undef, %while.body.i ]
+ %c = call fastcc signext i8 @next_char()
+ %c_10 = icmp eq i8 %c, 10
+ %c_13 = icmp eq i8 %c, 13
+ %c_10_or_13 = or i1 %c_10, %c_13
+ %next_maybe_undef = or i1 %maybe_undef, %c_10_or_13
+ %c_not_10_or_13 = xor i1 %c_10_or_13, true
+ br i1 %c_not_10_or_13, label %while.body.i, label %while.body.i.break
+
+while.body.i.break:
+ ; NEXT_MAYBE_UNDEF is never undef if here
+ br i1 %next_maybe_undef, label %while.body, label %return
+
+
+return:
+ ret void
+}