test/Transforms/PhaseOrdering/single-iteration-loop-sroa.ll

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt -S -O2 < %s | FileCheck %s

; Test a single-iteration loop that should get SROAd once we realize that fact.
; It should compile down to a bswap.

; The helper function exists to avoid IPSCCP breaking the loop too early.

define i16 @helper(i16 %0, i64 %x) {
; CHECK-LABEL: @helper(
; CHECK-NEXT:  start:
; CHECK-NEXT:    [[DATA:%.*]] = alloca [2 x i8], align 2
; CHECK-NEXT:    store i16 [[TMP0:%.*]], ptr [[DATA]], align 2
; CHECK-NEXT:    [[TMP1:%.*]] = getelementptr inbounds i8, ptr [[DATA]], i64 1
; CHECK-NEXT:    br label [[BB6_I_I:%.*]]
; CHECK:       bb6.i.i:
; CHECK-NEXT:    [[ITER_SROA_0_07_I_I:%.*]] = phi i64 [ [[TMP2:%.*]], [[BB6_I_I]] ], [ 0, [[START:%.*]] ]
; CHECK-NEXT:    [[_40_I_I:%.*]] = sub nsw i64 0, [[ITER_SROA_0_07_I_I]]
; CHECK-NEXT:    [[TMP2]] = add nuw nsw i64 [[ITER_SROA_0_07_I_I]], 1
; CHECK-NEXT:    [[_34_I_I:%.*]] = getelementptr inbounds [0 x i8], ptr [[DATA]], i64 0, i64 [[ITER_SROA_0_07_I_I]]
; CHECK-NEXT:    [[_39_I_I:%.*]] = getelementptr inbounds [0 x i8], ptr [[TMP1]], i64 0, i64 [[_40_I_I]]
; CHECK-NEXT:    [[TMP_0_COPYLOAD_I_I_I_I:%.*]] = load i8, ptr [[_34_I_I]], align 1
; CHECK-NEXT:    [[TMP2_0_COPYLOAD_I_I_I_I:%.*]] = load i8, ptr [[_39_I_I]], align 1
; CHECK-NEXT:    store i8 [[TMP2_0_COPYLOAD_I_I_I_I]], ptr [[_34_I_I]], align 1
; CHECK-NEXT:    store i8 [[TMP_0_COPYLOAD_I_I_I_I]], ptr [[_39_I_I]], align 1
; CHECK-NEXT:    [[EXITCOND_NOT_I_I:%.*]] = icmp eq i64 [[TMP2]], [[X:%.*]]
; CHECK-NEXT:    br i1 [[EXITCOND_NOT_I_I]], label [[EXIT:%.*]], label [[BB6_I_I]]
; CHECK:       exit:
; CHECK-NEXT:    [[DOTSROA_0_0_COPYLOAD:%.*]] = load i16, ptr [[DATA]], align 2
; CHECK-NEXT:    ret i16 [[DOTSROA_0_0_COPYLOAD]]
;
start:
  %data = alloca [2 x i8], align 2
  store i16 %0, ptr %data, align 2
  %1 = getelementptr inbounds i8, ptr %data, i64 2
  %2 = getelementptr inbounds i8, ptr %1, i64 -1
  br label %bb6.i.i

bb6.i.i:
  %iter.sroa.0.07.i.i = phi i64 [ %4, %bb6.i.i ], [ 0, %start ]
  %3 = xor i64 %iter.sroa.0.07.i.i, -1
  %_40.i.i = add nsw i64 1, %3
  %4 = add nuw nsw i64 %iter.sroa.0.07.i.i, 1
  %_34.i.i = getelementptr inbounds [0 x i8], ptr %data, i64 0, i64 %iter.sroa.0.07.i.i
  %_39.i.i = getelementptr inbounds [0 x i8], ptr %2, i64 0, i64 %_40.i.i
  %tmp.0.copyload.i.i.i.i = load i8, ptr %_34.i.i, align 1
  %tmp2.0.copyload.i.i.i.i = load i8, ptr %_39.i.i, align 1
  store i8 %tmp2.0.copyload.i.i.i.i, ptr %_34.i.i, align 1
  store i8 %tmp.0.copyload.i.i.i.i, ptr %_39.i.i, align 1
  %exitcond.not.i.i = icmp eq i64 %4, %x
  br i1 %exitcond.not.i.i, label %exit, label %bb6.i.i

exit:
  %.sroa.0.0.copyload = load i16, ptr %data, align 2
  ret i16 %.sroa.0.0.copyload
}

define i16 @test(i16 %arg) {
; CHECK-LABEL: @test(
; CHECK-NEXT:  bb6.i.i.i:
; CHECK-NEXT:    [[DATA_I_SROA_0_0_INSERT_INSERT:%.*]] = tail call i16 @llvm.bswap.i16(i16 [[ARG:%.*]])
; CHECK-NEXT:    ret i16 [[DATA_I_SROA_0_0_INSERT_INSERT]]
;
  %ret = call i16 @helper(i16 %arg, i64 1)
  ret i16 %ret
}