[NFC][SimplifyCFG] Add basic test for tail-merging `resume` function terminators

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py

; RUN: opt -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -sink-common-insts  -S < %s | FileCheck %s

; Test that we tail merge resume blocks and phi operands properly.

declare void @foo()

declare void @bar()

declare void @baz()

declare void @qux()

declare void @quux()

declare void @quuz()

define void @merge_simple(i1 %cond) personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {

; CHECK-LABEL: @merge_simple(

; CHECK-NEXT:    invoke void @foo()

; CHECK-NEXT:    to label [[INVOKE_CONT:%.*]] unwind label [[LPAD:%.*]]

; CHECK:       invoke.cont:

; CHECK-NEXT:    invoke void @bar()

; CHECK-NEXT:    to label [[INVOKE_CONT2:%.*]] unwind label [[LPAD2:%.*]]

; CHECK:       invoke.cont2:

; CHECK-NEXT:    ret void

; CHECK:       lpad:

; CHECK-NEXT:    [[LP:%.*]] = landingpad { i8*, i32 }

; CHECK-NEXT:    cleanup

; CHECK-NEXT:    call void @baz()

; CHECK-NEXT:    br i1 [[COND:%.*]], label [[RESUME0:%.*]], label [[RESUME1:%.*]]

; CHECK:       lpad2:

; CHECK-NEXT:    [[LP2:%.*]] = landingpad { i8*, i32 }

; CHECK-NEXT:    cleanup

; CHECK-NEXT:    call void @quuz()

; CHECK-NEXT:    resume { i8*, i32 } [[LP2]]

; CHECK:       resume0:

; CHECK-NEXT:    call void @qux()

; CHECK-NEXT:    resume { i8*, i32 } [[LP]]

; CHECK:       resume1:

; CHECK-NEXT:    call void @quux()

; CHECK-NEXT:    resume { i8*, i32 } [[LP]]

;

  invoke void @foo() to label %invoke.cont unwind label %lpad

invoke.cont:

  invoke void @bar()to label %invoke.cont2 unwind label %lpad2

  ret void

invoke.cont2:

  ret void

lpad:

  %lp = landingpad { i8*, i32 } cleanup

  call void @baz()

  br i1 %cond, label %resume0, label %resume1

lpad2:

  %lp2 = landingpad { i8*, i32 } cleanup

  call void @quuz()

  resume { i8*, i32 } %lp2

resume0:

  call void @qux()

  resume { i8*, i32 } %lp

resume1:

  call void @quux()

  resume { i8*, i32 } %lp

}

declare dso_local i32 @__gxx_personality_v0(...)