mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2024-11-24 03:33:20 +01:00
478de7c13b
Summary: Teach EarlyCSE about invariant.start intrinsic. Specifically, we can perform store-load, load-load forwarding over this call. Reviewers: majnemer, reames, dberlin, sanjoy Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D23268 llvm-svn: 278153
72 lines
2.0 KiB
LLVM
72 lines
2.0 KiB
LLVM
; RUN: opt < %s -S -early-cse | FileCheck %s
|
|
; RUN: opt < %s -S -passes=early-cse | FileCheck %s
|
|
|
|
declare {}* @llvm.invariant.start.p0i8(i64, i8* nocapture) nounwind readonly
|
|
declare void @llvm.invariant.end.p0i8({}*, i64, i8* nocapture) nounwind
|
|
|
|
; Check that we do load-load forwarding over invariant.start, since it does not
|
|
; clobber memory
|
|
define i8 @test1(i8 *%P) {
|
|
; CHECK-LABEL: @test1(
|
|
; CHECK-NEXT: %V1 = load i8, i8* %P
|
|
; CHECK-NEXT: %i = call {}* @llvm.invariant.start.p0i8(i64 1, i8* %P)
|
|
; CHECK-NEXT: ret i8 0
|
|
|
|
|
|
%V1 = load i8, i8* %P
|
|
%i = call {}* @llvm.invariant.start.p0i8(i64 1, i8* %P)
|
|
%V2 = load i8, i8* %P
|
|
%Diff = sub i8 %V1, %V2
|
|
ret i8 %Diff
|
|
}
|
|
|
|
|
|
; Trivial Store->load forwarding over invariant.start
|
|
define i8 @test2(i8 *%P) {
|
|
; CHECK-LABEL: @test2(
|
|
; CHECK-NEXT: store i8 42, i8* %P
|
|
; CHECK-NEXT: %i = call {}* @llvm.invariant.start.p0i8(i64 1, i8* %P)
|
|
; CHECK-NEXT: ret i8 42
|
|
|
|
|
|
store i8 42, i8* %P
|
|
%i = call {}* @llvm.invariant.start.p0i8(i64 1, i8* %P)
|
|
%V1 = load i8, i8* %P
|
|
ret i8 %V1
|
|
}
|
|
|
|
; We can DSE over invariant.start calls, since the first store to
|
|
; %P is valid, and the second store is actually unreachable based on semantics
|
|
; of invariant.start.
|
|
define void @test3(i8* %P) {
|
|
|
|
; CHECK-LABEL: @test3(
|
|
; CHECK-NEXT: %i = call {}* @llvm.invariant.start.p0i8(i64 1, i8* %P)
|
|
; CHECK-NEXT: store i8 60, i8* %P
|
|
|
|
|
|
store i8 50, i8* %P
|
|
%i = call {}* @llvm.invariant.start.p0i8(i64 1, i8* %P)
|
|
store i8 60, i8* %P
|
|
ret void
|
|
}
|
|
|
|
|
|
; FIXME: Now the first store can actually be eliminated, since there is no read within
|
|
; the invariant region, between start and end.
|
|
define void @test4(i8* %P) {
|
|
|
|
; CHECK-LABEL: @test4(
|
|
; CHECK-NEXT: store i8 50, i8* %P
|
|
; CHECK-NEXT: %i = call {}* @llvm.invariant.start.p0i8(i64 1, i8* %P)
|
|
; CHECK-NEXT: call void @llvm.invariant.end.p0i8({}* %i, i64 1, i8* %P)
|
|
; CHECK-NEXT: store i8 60, i8* %P
|
|
|
|
|
|
store i8 50, i8* %P
|
|
%i = call {}* @llvm.invariant.start.p0i8(i64 1, i8* %P)
|
|
call void @llvm.invariant.end.p0i8({}* %i, i64 1, i8* %P)
|
|
store i8 60, i8* %P
|
|
ret void
|
|
}
|