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llvm-mirror/test/Transforms/LICM/preheader-safe.ll
Max Kazantsev 86590965e8 [LICM] Use ICFLoopSafetyInfo in LICM
This patch makes LICM use `ICFLoopSafetyInfo` that is a smarter version
of LoopSafetyInfo that leverages power of Implicit Control Flow Tracking
to keep track of throwing instructions and give less pessimistic answers
to queries related to throws.

The ICFLoopSafetyInfo itself has been introduced in rL344601. This patch
enables it in LICM only.

Differential Revision: https://reviews.llvm.org/D50377
Reviewed By: apilipenko

llvm-svn: 346201
2018-11-06 02:44:49 +00:00

152 lines
4.1 KiB
LLVM

; RUN: opt -S -licm < %s | FileCheck %s
; RUN: opt -aa-pipeline=basic-aa -passes='require<aa>,require<targetir>,require<scalar-evolution>,require<opt-remark-emit>,loop(licm)' -S %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, 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
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, i1* %cond) {
; CHECK-LABEL: throw_header_after
; 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
call void @use(i64 %div)
br label %loop
}
define void @throw_header_after_rec(i64* %xp, i64* %yp, i1* %cond) {
; CHECK-LABEL: throw_header_after_rec
; CHECK: %x = load i64, i64* %xp
; CHECK: %y = load i64, i64* %yp
; CHECK: %div = udiv i64 %x, %y
; CHECK-LABEL: loop
; CHECK: call void @use(i64 %div)
entry:
br label %loop
loop: ; preds = %entry, %for.inc
%x = load i64, i64* %xp
%y = load i64, i64* %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(i64* %xp, i64* %yp, i1* %cond) {
; CHECK-LABEL: throw_header_after_nonfirst
; CHECK: %y = load i64, i64* %yp
; CHECK-LABEL: loop
; CHECK: %x = load i64, i64* %gep
; CHECK: %div = udiv i64 %x, %y
; CHECK: call void @use(i64 %div)
entry:
br label %loop
loop: ; preds = %entry, %for.inc
%iv = phi i64 [0, %entry], [%div, %loop]
%gep = getelementptr i64, i64* %xp, i64 %iv
%x = load i64, i64* %gep
%y = load i64, i64* %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, i1* %cond) {
; CHECK-LABEL: throw_header_before
; CHECK-LABEL: loop
; CHECK: %div = udiv i64 %x, %y
; CHECK: call void @use(i64 %div)
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: 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
}
; Positive test - can hoist something that happens before thrower.
define void @nothrow_header_pos(i64 %x, i64 %y, i1 %cond) {
; CHECK-LABEL: nothrow_header_pos
; 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
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: nothrow_header_neg
; CHECK-LABEL: entry
; CHECK-LABEL: loop
; CHECK: call void @maythrow()
; 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:
call void @maythrow()
%div = udiv i64 %x, %y
call void @use(i64 %div)
br label %loop
}