llvm/test/Transforms/SimpleLoopUnswitch/preserve-scev-exiting-multiple-loops.ll

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

; We run -passes=indvars before -passes=simple-loop-unswitch to compute SCEV exit counts before
; running -simple-loop-unswitch.
; RUN:  opt -passes=indvars,simple-loop-unswitch -S %s -verify-scev | FileCheck %s

; Test for PR43972.

; We have a 3 nested loops (l1 <- l2 <- l3). %for.cond.5 is the exit block of
; l3 and the loop for it is l2. But it is also the exiting block of l1. That
; means we have to invalidate l1 to preserve SCEV.

define void @f() {
; CHECK-LABEL: @f(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    [[LNOT:%.*]] = xor i1 undef, true
; CHECK-NEXT:    br label [[FOR_COND:%.*]]
; CHECK:       for.cond.loopexit:
; CHECK-NEXT:    br label [[FOR_COND]]
; CHECK:       for.cond:
; CHECK-NEXT:    br label [[FOR_BODY:%.*]]
; CHECK:       for.cond1:
; CHECK-NEXT:    br i1 true, label [[FOR_BODY]], label [[FOR_COND_LOOPEXIT:%.*]]
; CHECK:       for.body:
; CHECK-NEXT:    br i1 [[LNOT]], label [[FOR_BODY_SPLIT:%.*]], label [[FOR_COND5_SPLIT:%.*]]
; CHECK:       for.body.split:
; CHECK-NEXT:    br label [[LAND_RHS:%.*]]
; CHECK:       for.cond2:
; CHECK-NEXT:    br i1 true, label [[LAND_RHS]], label [[FOR_COND5:%.*]]
; CHECK:       land.rhs:
; CHECK-NEXT:    br label [[FOR_COND2:%.*]]
; CHECK:       for.cond5:
; CHECK-NEXT:    br label [[FOR_COND5_SPLIT]]
; CHECK:       for.cond5.split:
; CHECK-NEXT:    br i1 true, label [[FOR_BODY7:%.*]], label [[FOR_COND1:%.*]]
; CHECK:       for.body7:
; CHECK-NEXT:    ret void
;
entry:
  %lnot = xor i1 undef, true
  br label %for.cond

for.cond:                                         ; preds = %for.cond1, %entry
  br label %for.body

for.cond1:                                        ; preds = %for.cond5
  br i1 true, label %for.body, label %for.cond

for.body:                                         ; preds = %for.cond1, %for.cond
  br label %land.rhs

for.cond2:                                        ; preds = %land.rhs
  br i1 true, label %land.rhs, label %for.cond5

land.rhs:                                         ; preds = %for.cond2, %for.body
  br i1 %lnot, label %for.cond2, label %for.cond5

for.cond5:                                        ; preds = %land.rhs, %for.cond2
  br i1 true, label %for.body7, label %for.cond1

for.body7:                                        ; preds = %for.cond5
  ret void
}