test/Transforms/LICM/promote-single-thread.ll

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt -S -passes=licm < %s | FileCheck %s --check-prefixes=CHECK,MT
; RUN: opt -S -passes=licm -licm-force-thread-model-single < %s | FileCheck %s --check-prefixes=CHECK,ST

@g = external global i32
@c = external constant i32

declare void @capture(ptr)

; Even in single-thread mode, can only perform load-only promotion for globals,
; because we might not have provenance to write to the global. See
; promote_global_noalias for an example of the issue.
define void @promote_global(i1 %c, i1 %c2) {
; CHECK-LABEL: @promote_global(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    [[G_PROMOTED:%.*]] = load i32, ptr @g, align 4
; CHECK-NEXT:    br label [[LOOP:%.*]]
; CHECK:       loop:
; CHECK-NEXT:    [[V_INC2:%.*]] = phi i32 [ [[V_INC1:%.*]], [[LATCH:%.*]] ], [ [[G_PROMOTED]], [[ENTRY:%.*]] ]
; CHECK-NEXT:    br i1 [[C:%.*]], label [[IF:%.*]], label [[LATCH]]
; CHECK:       if:
; CHECK-NEXT:    [[V_INC:%.*]] = add i32 [[V_INC2]], 1
; CHECK-NEXT:    store i32 [[V_INC]], ptr @g, align 4
; CHECK-NEXT:    br label [[LATCH]]
; CHECK:       latch:
; CHECK-NEXT:    [[V_INC1]] = phi i32 [ [[V_INC]], [[IF]] ], [ [[V_INC2]], [[LOOP]] ]
; CHECK-NEXT:    br i1 [[C2:%.*]], label [[EXIT:%.*]], label [[LOOP]]
; CHECK:       exit:
; CHECK-NEXT:    ret void
;
entry:
  br label %loop

loop:
  br i1 %c, label %if, label %latch

if:
  %v = load i32, ptr @g
  %v.inc = add i32 %v, 1
  store i32 %v.inc, ptr @g
  br label %latch

latch:
  br i1 %c2, label %exit, label %loop

exit:
  ret void
}

; The store can never be promoted here, because the global is constant, and
; the store could trap.
define void @promote_constant_global(i1 %c, i1 %c2) {
; CHECK-LABEL: @promote_constant_global(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    [[V:%.*]] = load i32, ptr @c, align 4
; CHECK-NEXT:    [[V_INC:%.*]] = add i32 [[V]], 1
; CHECK-NEXT:    br label [[LOOP:%.*]]
; CHECK:       loop:
; CHECK-NEXT:    br i1 [[C:%.*]], label [[IF:%.*]], label [[LATCH:%.*]]
; CHECK:       if:
; CHECK-NEXT:    store i32 [[V_INC]], ptr @c, align 4
; CHECK-NEXT:    br label [[LATCH]]
; CHECK:       latch:
; CHECK-NEXT:    br i1 [[C2:%.*]], label [[EXIT:%.*]], label [[LOOP]]
; CHECK:       exit:
; CHECK-NEXT:    ret void
;
entry:
  br label %loop

loop:
  br i1 %c, label %if, label %latch

if:
  %v = load i32, ptr @c
  %v.inc = add i32 %v, 1
  store i32 %v.inc, ptr @c
  br label %latch

latch:
  br i1 %c2, label %exit, label %loop

exit:
  ret void
}

; if %c is false and %ptr == @g, then this should store 42 to the pointer.
; However, if we perform load+store promotion, then we would instead store the
; original value of the global.
define void @promote_global_noalias(i1 %c, i1 %c2, ptr noalias %ptr) {
; CHECK-LABEL: @promote_global_noalias(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    [[G_PROMOTED:%.*]] = load i32, ptr @g, align 4
; CHECK-NEXT:    br label [[LOOP:%.*]]
; CHECK:       loop:
; CHECK-NEXT:    [[V_INC2:%.*]] = phi i32 [ [[V_INC1:%.*]], [[LATCH:%.*]] ], [ [[G_PROMOTED]], [[ENTRY:%.*]] ]
; CHECK-NEXT:    br i1 [[C:%.*]], label [[IF:%.*]], label [[ELSE:%.*]]
; CHECK:       if:
; CHECK-NEXT:    [[V_INC:%.*]] = add i32 [[V_INC2]], 1
; CHECK-NEXT:    store i32 [[V_INC]], ptr @g, align 4
; CHECK-NEXT:    br label [[LATCH]]
; CHECK:       else:
; CHECK-NEXT:    store i32 42, ptr [[PTR:%.*]], align 4
; CHECK-NEXT:    br label [[LATCH]]
; CHECK:       latch:
; CHECK-NEXT:    [[V_INC1]] = phi i32 [ [[V_INC2]], [[ELSE]] ], [ [[V_INC]], [[IF]] ]
; CHECK-NEXT:    br i1 [[C2:%.*]], label [[EXIT:%.*]], label [[LOOP]]
; CHECK:       exit:
; CHECK-NEXT:    ret void
;
entry:
  br label %loop

loop:
  br i1 %c, label %if, label %else

if:
  %v = load i32, ptr @g
  %v.inc = add i32 %v, 1
  store i32 %v.inc, ptr @g
  br label %latch

else:
  store i32 42, ptr %ptr
  br label %latch

latch:
  br i1 %c2, label %exit, label %loop

exit:
  ret void
}

; In single-thread mode both loads and stores can be promoted. In multi-thread
; mode only loads can be promoted, as a different thread might write to the
; captured alloca.
define void @promote_captured_alloca(i1 %c, i1 %c2) {
; MT-LABEL: @promote_captured_alloca(
; MT-NEXT:  entry:
; MT-NEXT:    [[A:%.*]] = alloca i32, align 4
; MT-NEXT:    call void @capture(ptr [[A]])
; MT-NEXT:    [[A_PROMOTED:%.*]] = load i32, ptr [[A]], align 4
; MT-NEXT:    br label [[LOOP:%.*]]
; MT:       loop:
; MT-NEXT:    [[V_INC2:%.*]] = phi i32 [ [[V_INC1:%.*]], [[LATCH:%.*]] ], [ [[A_PROMOTED]], [[ENTRY:%.*]] ]
; MT-NEXT:    br i1 [[C:%.*]], label [[IF:%.*]], label [[LATCH]]
; MT:       if:
; MT-NEXT:    [[V_INC:%.*]] = add i32 [[V_INC2]], 1
; MT-NEXT:    store i32 [[V_INC]], ptr [[A]], align 4
; MT-NEXT:    br label [[LATCH]]
; MT:       latch:
; MT-NEXT:    [[V_INC1]] = phi i32 [ [[V_INC]], [[IF]] ], [ [[V_INC2]], [[LOOP]] ]
; MT-NEXT:    br i1 [[C2:%.*]], label [[EXIT:%.*]], label [[LOOP]]
; MT:       exit:
; MT-NEXT:    ret void
;
; ST-LABEL: @promote_captured_alloca(
; ST-NEXT:  entry:
; ST-NEXT:    [[A:%.*]] = alloca i32, align 4
; ST-NEXT:    call void @capture(ptr [[A]])
; ST-NEXT:    [[A_PROMOTED:%.*]] = load i32, ptr [[A]], align 4
; ST-NEXT:    br label [[LOOP:%.*]]
; ST:       loop:
; ST-NEXT:    [[V_INC2:%.*]] = phi i32 [ [[V_INC1:%.*]], [[LATCH:%.*]] ], [ [[A_PROMOTED]], [[ENTRY:%.*]] ]
; ST-NEXT:    br i1 [[C:%.*]], label [[IF:%.*]], label [[LATCH]]
; ST:       if:
; ST-NEXT:    [[V_INC:%.*]] = add i32 [[V_INC2]], 1
; ST-NEXT:    br label [[LATCH]]
; ST:       latch:
; ST-NEXT:    [[V_INC1]] = phi i32 [ [[V_INC]], [[IF]] ], [ [[V_INC2]], [[LOOP]] ]
; ST-NEXT:    br i1 [[C2:%.*]], label [[EXIT:%.*]], label [[LOOP]]
; ST:       exit:
; ST-NEXT:    [[V_INC1_LCSSA:%.*]] = phi i32 [ [[V_INC1]], [[LATCH]] ]
; ST-NEXT:    store i32 [[V_INC1_LCSSA]], ptr [[A]], align 4
; ST-NEXT:    ret void
;
entry:
  %a = alloca i32
  call void @capture(ptr %a)
  br label %loop

loop:
  br i1 %c, label %if, label %latch

if:
  %v = load i32, ptr %a
  %v.inc = add i32 %v, 1
  store i32 %v.inc, ptr %a
  br label %latch

latch:
  br i1 %c2, label %exit, label %loop

exit:
  ret void
}

; The store cannot be promoted here, because we do not know whether the
; argument memory is writable.
define void @promote_arg(ptr noalias dereferenceable(4) align 4 %arg, i1 %c, i1 %c2) {
; CHECK-LABEL: @promote_arg(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    [[ARG_PROMOTED:%.*]] = load i32, ptr [[ARG:%.*]], align 4
; CHECK-NEXT:    br label [[LOOP:%.*]]
; CHECK:       loop:
; CHECK-NEXT:    [[V_INC2:%.*]] = phi i32 [ [[V_INC1:%.*]], [[LATCH:%.*]] ], [ [[ARG_PROMOTED]], [[ENTRY:%.*]] ]
; CHECK-NEXT:    br i1 [[C:%.*]], label [[IF:%.*]], label [[LATCH]]
; CHECK:       if:
; CHECK-NEXT:    [[V_INC:%.*]] = add i32 [[V_INC2]], 1
; CHECK-NEXT:    store i32 [[V_INC]], ptr [[ARG]], align 4
; CHECK-NEXT:    br label [[LATCH]]
; CHECK:       latch:
; CHECK-NEXT:    [[V_INC1]] = phi i32 [ [[V_INC]], [[IF]] ], [ [[V_INC2]], [[LOOP]] ]
; CHECK-NEXT:    br i1 [[C2:%.*]], label [[EXIT:%.*]], label [[LOOP]]
; CHECK:       exit:
; CHECK-NEXT:    ret void
;
entry:
  br label %loop

loop:
  br i1 %c, label %if, label %latch

if:
  %v = load i32, ptr %arg
  %v.inc = add i32 %v, 1
  store i32 %v.inc, ptr %arg
  br label %latch

latch:
  br i1 %c2, label %exit, label %loop

exit:
  ret void
}