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

; RUN: opt -S -licm < %s | FileCheck %s

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

define void @nothrow(i64 %x, i64 %y, i1* %cond) {
; CHECK-LABEL: nothrow
; CHECK-LABEL: entry
; CHECK: %div = udiv i64 %x, %y
; CHECK-LABEL: loop
; CHECK: call void @use_nothrow(i64 %div)
entry:
  br label %loop

loop:                                         ; preds = %entry, %for.inc
  %div = udiv i64 %x, %y
  call void @use_nothrow(i64 %div)
  br label %loop
}
; Negative test
define void @throw_header(i64 %x, i64 %y, i1* %cond) {
; CHECK-LABEL: throw_header
; CHECK-LABEL: loop
; CHECK: %div = udiv i64 %x, %y
; CHECK: call void @use(i64 %div)
entry:
  br label %loop

loop:                                         ; preds = %entry, %for.inc
  %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: nothrow_header
; CHECK-LABEL: entry
; CHECK: %div = udiv i64 %x, %y
; CHECK-LABEL: loop
; CHECK: call void @use(i64 %div)
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
}
; Negative test - can't move out of throwing block
define void @nothrow_header_neg(i64 %x, i64 %y, i1 %cond) {
; CHECK-LABEL: nothrow_header_neg
; CHECK-LABEL: entry
; CHECK-LABEL: loop
; CHECK: %div = udiv i64 %x, %y
; CHECK: call void @use(i64 %div)
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
}