test/Transforms/Mem2Reg/preserve-nonnull-load-metadata.ll

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -passes=mem2reg -S | FileCheck %s

; This tests that mem2reg preserves the !nonnull metadata on loads
; from allocas that get optimized out.

; Check the case where the alloca in question has a single store.
define float* @single_store(float** %arg) {
; CHECK-LABEL: @single_store(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    [[ARG_LOAD:%.*]] = load float*, float** [[ARG:%.*]], align 8
; CHECK-NEXT:    [[TMP0:%.*]] = icmp ne float* [[ARG_LOAD]], null
; CHECK-NEXT:    call void @llvm.assume(i1 [[TMP0]])
; CHECK-NEXT:    ret float* [[ARG_LOAD]]
;
entry:
  %buf = alloca float*
  %arg.load = load float*, float** %arg, align 8
  store float* %arg.load, float** %buf, align 8
  %buf.load = load float*, float **%buf, !nonnull !0
  ret float* %buf.load
}

; Check the case where the alloca in question has more than one
; store but still within one basic block.
define float* @single_block(float** %arg) {
; CHECK-LABEL: @single_block(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    [[ARG_LOAD:%.*]] = load float*, float** [[ARG:%.*]], align 8
; CHECK-NEXT:    [[TMP0:%.*]] = icmp ne float* [[ARG_LOAD]], null
; CHECK-NEXT:    call void @llvm.assume(i1 [[TMP0]])
; CHECK-NEXT:    ret float* [[ARG_LOAD]]
;
entry:
  %buf = alloca float*
  %arg.load = load float*, float** %arg, align 8
  store float* null, float** %buf, align 8
  store float* %arg.load, float** %buf, align 8
  %buf.load = load float*, float **%buf, !nonnull !0
  ret float* %buf.load
}

; Check the case where the alloca in question has more than one
; store and also reads ands writes in multiple blocks.
define float* @multi_block(float** %arg) {
; CHECK-LABEL: @multi_block(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    [[ARG_LOAD:%.*]] = load float*, float** [[ARG:%.*]], align 8
; CHECK-NEXT:    br label [[NEXT:%.*]]
; CHECK:       next:
; CHECK-NEXT:    [[TMP0:%.*]] = icmp ne float* [[ARG_LOAD]], null
; CHECK-NEXT:    call void @llvm.assume(i1 [[TMP0]])
; CHECK-NEXT:    ret float* [[ARG_LOAD]]
;
entry:
  %buf = alloca float*
  %arg.load = load float*, float** %arg, align 8
  store float* null, float** %buf, align 8
  br label %next
next:
  store float* %arg.load, float** %buf, align 8
  %buf.load = load float*, float** %buf, !nonnull !0
  ret float* %buf.load
}

; Check that we don't add an assume if it's not
; necessary i.e. the value is already implied to be nonnull
define float* @no_assume(float** %arg) {
; CHECK-LABEL: @no_assume(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    [[ARG_LOAD:%.*]] = load float*, float** [[ARG:%.*]], align 8
; CHECK-NEXT:    [[CN:%.*]] = icmp ne float* [[ARG_LOAD]], null
; CHECK-NEXT:    br i1 [[CN]], label [[NEXT:%.*]], label [[FIN:%.*]]
; CHECK:       next:
; CHECK-NEXT:    ret float* [[ARG_LOAD]]
; CHECK:       fin:
; CHECK-NEXT:    ret float* null
;
entry:
  %buf = alloca float*
  %arg.load = load float*, float** %arg, align 8
  %cn = icmp ne float* %arg.load, null
  br i1 %cn, label %next, label %fin
next:
; At this point the above nonnull check ensures that
; the value %arg.load is nonnull in this block and thus
; we need not add the assume.
  store float* %arg.load, float** %buf, align 8
  %buf.load = load float*, float** %buf, !nonnull !0
  ret float* %buf.load
fin:
  ret float* null
}

define float* @no_store_single_load() {
; CHECK-LABEL: @no_store_single_load(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    [[TMP0:%.*]] = icmp ne float* undef, null
; CHECK-NEXT:    call void @llvm.assume(i1 [[TMP0]])
; CHECK-NEXT:    ret float* undef
;
entry:
  %buf = alloca float*
  %buf.load = load float*, float **%buf, !nonnull !0
  ret float* %buf.load
}

define float* @no_store_multiple_loads(i1 %c) {
; CHECK-LABEL: @no_store_multiple_loads(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    br i1 [[C:%.*]], label [[IF:%.*]], label [[ELSE:%.*]]
; CHECK:       if:
; CHECK-NEXT:    [[TMP0:%.*]] = icmp ne float* undef, null
; CHECK-NEXT:    call void @llvm.assume(i1 [[TMP0]])
; CHECK-NEXT:    ret float* undef
; CHECK:       else:
; CHECK-NEXT:    [[TMP1:%.*]] = icmp ne float* undef, null
; CHECK-NEXT:    call void @llvm.assume(i1 [[TMP1]])
; CHECK-NEXT:    ret float* undef
;
entry:
  %buf = alloca float*
  br i1 %c, label %if, label %else

if:
  %buf.load = load float*, float **%buf, !nonnull !0
  ret float* %buf.load

  else:
  %buf.load2 = load float*, float **%buf, !nonnull !0
  ret float* %buf.load2
}

!0 = !{}