; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 3

;; Check that -enable-loop-header-duplication at Oz enables certain types of
;; optimizations, for example replacing the loop body w/ a call to memset. If
;; loop idiom recognition begins to recognize unrotated loops, this test will
;; need to be updated.

; RUN: opt -passes='default<Oz>' -S < %s  | FileCheck %s --check-prefix=NOROTATION
; RUN: opt -passes='default<Oz>' -S  -enable-loop-header-duplication < %s  | FileCheck %s --check-prefix=ROTATION
; RUN: opt -passes='default<O2>' -S  < %s  | FileCheck %s --check-prefix=ROTATION

define void @test(i8* noalias nonnull align 1 %start, i8* %end) unnamed_addr {
; NOROTATION-LABEL: define void @test(
; NOROTATION-SAME: ptr noalias nonnull writeonly align 1 [[START:%.*]], ptr readnone [[END:%.*]]) unnamed_addr #[[ATTR0:[0-9]+]] {
; NOROTATION-NEXT:  entry:
; NOROTATION-NEXT:    br label [[LOOP_HEADER:%.*]]
; NOROTATION:       loop.header:
; NOROTATION-NEXT:    [[PTR_IV:%.*]] = phi ptr [ [[START]], [[ENTRY:%.*]] ], [ [[PTR_IV_NEXT:%.*]], [[LOOP_LATCH:%.*]] ]
; NOROTATION-NEXT:    [[_12_I:%.*]] = icmp eq ptr [[PTR_IV]], [[END]]
; NOROTATION-NEXT:    br i1 [[_12_I]], label [[EXIT:%.*]], label [[LOOP_LATCH]]
; NOROTATION:       loop.latch:
; NOROTATION-NEXT:    [[PTR_IV_NEXT]] = getelementptr inbounds nuw i8, ptr [[PTR_IV]], i64 1
; NOROTATION-NEXT:    store i8 1, ptr [[PTR_IV]], align 1
; NOROTATION-NEXT:    br label [[LOOP_HEADER]]
; NOROTATION:       exit:
; NOROTATION-NEXT:    ret void
;
; ROTATION-LABEL: define void @test(
; ROTATION-SAME: ptr noalias nonnull writeonly align 1 [[START:%.*]], ptr readnone [[END:%.*]]) unnamed_addr #[[ATTR0:[0-9]+]] {
; ROTATION-NEXT:  entry:
; ROTATION-NEXT:    [[_12_I1:%.*]] = icmp eq ptr [[START]], [[END]]
; ROTATION-NEXT:    br i1 [[_12_I1]], label [[EXIT:%.*]], label [[LOOP_LATCH_PREHEADER:%.*]]
; ROTATION:       loop.latch.preheader:
; ROTATION-NEXT:    [[END3:%.*]] = ptrtoint ptr [[END]] to i64
; ROTATION-NEXT:    [[START4:%.*]] = ptrtoint ptr [[START]] to i64
; ROTATION-NEXT:    [[TMP0:%.*]] = sub i64 [[END3]], [[START4]]
; ROTATION-NEXT:    tail call void @llvm.memset.p0.i64(ptr nonnull align 1 [[START]], i8 1, i64 [[TMP0]], i1 false)
; ROTATION-NEXT:    br label [[EXIT]]
; ROTATION:       exit:
; ROTATION-NEXT:    ret void
;
entry:
  br label %loop.header

loop.header:
  %ptr.iv = phi i8* [ %start, %entry ], [ %ptr.iv.next, %loop.latch ]
  %_12.i = icmp eq i8* %ptr.iv, %end
  br i1 %_12.i, label %exit, label %loop.latch

loop.latch:
  %ptr.iv.next = getelementptr inbounds i8, i8* %ptr.iv, i64 1
  store i8 1, i8* %ptr.iv, align 1
  br label %loop.header

exit:
  ret void
}