llvm/test/Transforms/LICM/preheader-safe.ll

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 6
; RUN: opt -S -passes=licm < %s | FileCheck %s

declare void @use_nothrow(i64 %a) nounwind
declare void @use(i64 %a)
declare void @maythrow()

define void @nothrow(i64 %x, i64 %y, ptr %cond) {
; CHECK-LABEL: define void @nothrow(
; CHECK-SAME: i64 [[X:%.*]], i64 [[Y:%.*]], ptr [[COND:%.*]]) {
; CHECK-NEXT:  [[ENTRY:.*:]]
; CHECK-NEXT:    [[DIV:%.*]] = udiv i64 [[X]], [[Y]]
; CHECK-NEXT:    br label %[[LOOP:.*]]
; CHECK:       [[LOOP]]:
; CHECK-NEXT:    br label %[[LOOP2:.*]]
; CHECK:       [[LOOP2]]:
; CHECK-NEXT:    call void @use_nothrow(i64 [[DIV]])
; CHECK-NEXT:    br label %[[LOOP]]
;
entry:
  br label %loop

loop:                                         ; preds = %entry, %for.inc
  %div = udiv i64 %x, %y
  br label %loop2

loop2:
  call void @use_nothrow(i64 %div)
  br label %loop
}

; The udiv is guarantee to execute if the loop is
define void @throw_header_after(i64 %x, i64 %y, ptr %cond) {
; CHECK-LABEL: define void @throw_header_after(
; CHECK-SAME: i64 [[X:%.*]], i64 [[Y:%.*]], ptr [[COND:%.*]]) {
; CHECK-NEXT:  [[ENTRY:.*:]]
; CHECK-NEXT:    [[DIV:%.*]] = udiv i64 [[X]], [[Y]]
; CHECK-NEXT:    br label %[[LOOP:.*]]
; CHECK:       [[LOOP]]:
; CHECK-NEXT:    call void @use(i64 [[DIV]])
; CHECK-NEXT:    br label %[[LOOP]]
;
entry:
  br label %loop

loop:                                         ; preds = %entry, %for.inc
  %div = udiv i64 %x, %y
  call void @use(i64 %div)
  br label %loop
}

define void @throw_header_after_rec(ptr %xp, ptr %yp, ptr %cond) {
; CHECK-LABEL: define void @throw_header_after_rec(
; CHECK-SAME: ptr [[XP:%.*]], ptr [[YP:%.*]], ptr [[COND:%.*]]) {
; CHECK-NEXT:  [[ENTRY:.*:]]
; CHECK-NEXT:    [[X:%.*]] = load i64, ptr [[XP]], align 4
; CHECK-NEXT:    [[Y:%.*]] = load i64, ptr [[YP]], align 4
; CHECK-NEXT:    [[DIV:%.*]] = udiv i64 [[X]], [[Y]]
; CHECK-NEXT:    br label %[[LOOP:.*]]
; CHECK:       [[LOOP]]:
; CHECK-NEXT:    call void @use(i64 [[DIV]]) #[[ATTR1:[0-9]+]]
; CHECK-NEXT:    br label %[[LOOP]]
;
entry:
  br label %loop

loop:                                         ; preds = %entry, %for.inc
  %x = load i64, ptr %xp
  %y = load i64, ptr %yp
  %div = udiv i64 %x, %y
  call void @use(i64 %div) readonly
  br label %loop
}

; Similiar to the above, but the hoistable instruction (%y in this case)
; happens not to be the first instruction in the block.
define void @throw_header_after_nonfirst(ptr %xp, ptr %yp, ptr %cond) {
; CHECK-LABEL: define void @throw_header_after_nonfirst(
; CHECK-SAME: ptr [[XP:%.*]], ptr [[YP:%.*]], ptr [[COND:%.*]]) {
; CHECK-NEXT:  [[ENTRY:.*]]:
; CHECK-NEXT:    [[Y:%.*]] = load i64, ptr [[YP]], align 4
; CHECK-NEXT:    br label %[[LOOP:.*]]
; CHECK:       [[LOOP]]:
; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ 0, %[[ENTRY]] ], [ [[DIV:%.*]], %[[LOOP]] ]
; CHECK-NEXT:    [[GEP:%.*]] = getelementptr i64, ptr [[XP]], i64 [[IV]]
; CHECK-NEXT:    [[X:%.*]] = load i64, ptr [[GEP]], align 4
; CHECK-NEXT:    [[DIV]] = udiv i64 [[X]], [[Y]]
; CHECK-NEXT:    call void @use(i64 [[DIV]]) #[[ATTR1]]
; CHECK-NEXT:    br label %[[LOOP]]
;
entry:
  br label %loop

loop:                                         ; preds = %entry, %for.inc
  %iv = phi i64 [0, %entry], [%div, %loop]
  %gep = getelementptr i64, ptr %xp, i64 %iv
  %x = load i64, ptr %gep
  %y = load i64, ptr %yp
  %div = udiv i64 %x, %y
  call void @use(i64 %div) readonly
  br label %loop
}

; Negative test
define void @throw_header_before(i64 %x, i64 %y, ptr %cond) {
; CHECK-LABEL: define void @throw_header_before(
; CHECK-SAME: i64 [[X:%.*]], i64 [[Y:%.*]], ptr [[COND:%.*]]) {
; CHECK-NEXT:  [[ENTRY:.*:]]
; CHECK-NEXT:    br label %[[LOOP:.*]]
; CHECK:       [[LOOP]]:
; CHECK-NEXT:    call void @maythrow()
; CHECK-NEXT:    [[DIV:%.*]] = udiv i64 [[X]], [[Y]]
; CHECK-NEXT:    call void @use(i64 [[DIV]])
; CHECK-NEXT:    br label %[[LOOP]]
;
entry:
  br label %loop

loop:                                         ; preds = %entry, %for.inc
  call void @maythrow()
  %div = udiv i64 %x, %y
  call void @use(i64 %div)
  br label %loop
}

; The header is known no throw, but the loop is not.  We can
; still lift out of the header.
define void @nothrow_header(i64 %x, i64 %y, i1 %cond) {
; CHECK-LABEL: define void @nothrow_header(
; CHECK-SAME: i64 [[X:%.*]], i64 [[Y:%.*]], i1 [[COND:%.*]]) {
; CHECK-NEXT:  [[ENTRY:.*:]]
; CHECK-NEXT:    [[DIV:%.*]] = udiv i64 [[X]], [[Y]]
; CHECK-NEXT:    br label %[[LOOP:.*]]
; CHECK:       [[LOOP]]:
; CHECK-NEXT:    br i1 [[COND]], label %[[LOOP_IF:.*]], label %[[EXIT:.*]]
; CHECK:       [[LOOP_IF]]:
; CHECK-NEXT:    call void @use(i64 [[DIV]])
; CHECK-NEXT:    br label %[[LOOP]]
; CHECK:       [[EXIT]]:
; CHECK-NEXT:    ret void
;
entry:
  br label %loop
loop:                                         ; preds = %entry, %for.inc
  %div = udiv i64 %x, %y
  br i1 %cond, label %loop-if, label %exit
loop-if:
  call void @use(i64 %div)
  br label %loop
exit:
  ret void
}

; Positive test - can hoist something that happens before thrower.
define void @nothrow_header_pos(i64 %x, i64 %y, i1 %cond) {
; CHECK-LABEL: define void @nothrow_header_pos(
; CHECK-SAME: i64 [[X:%.*]], i64 [[Y:%.*]], i1 [[COND:%.*]]) {
; CHECK-NEXT:  [[ENTRY:.*:]]
; CHECK-NEXT:    [[DIV:%.*]] = udiv i64 [[X]], [[Y]]
; CHECK-NEXT:    br label %[[LOOP:.*]]
; CHECK:       [[LOOP]]:
; CHECK-NEXT:    br label %[[LOOP_IF:.*]]
; CHECK:       [[LOOP_IF]]:
; CHECK-NEXT:    call void @use(i64 [[DIV]])
; CHECK-NEXT:    br label %[[LOOP]]
;
entry:
  br label %loop
loop:                                         ; preds = %entry, %for.inc
  br label %loop-if
loop-if:
  %div = udiv i64 %x, %y
  call void @use(i64 %div)
  br label %loop
}


; Negative test - can't move out of throwing block
define void @nothrow_header_neg(i64 %x, i64 %y, i1 %cond) {
; CHECK-LABEL: define void @nothrow_header_neg(
; CHECK-SAME: i64 [[X:%.*]], i64 [[Y:%.*]], i1 [[COND:%.*]]) {
; CHECK-NEXT:  [[ENTRY:.*:]]
; CHECK-NEXT:    br label %[[LOOP:.*]]
; CHECK:       [[LOOP]]:
; CHECK-NEXT:    br label %[[LOOP_IF:.*]]
; CHECK:       [[LOOP_IF]]:
; CHECK-NEXT:    call void @maythrow()
; CHECK-NEXT:    [[DIV:%.*]] = udiv i64 [[X]], [[Y]]
; CHECK-NEXT:    call void @use(i64 [[DIV]])
; CHECK-NEXT:    br label %[[LOOP]]
;
entry:
  br label %loop
loop:                                         ; preds = %entry, %for.inc
  br label %loop-if
loop-if:
  call void @maythrow()
  %div = udiv i64 %x, %y
  call void @use(i64 %div)
  br label %loop
}