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llvm-project/llvm/test/Analysis/MemorySSA/lifetime-simple.ll

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Support for lifetime begin/end markers in the MemorySSA use optimizer Summary: Depends on D23072 Reviewers: george.burgess.iv Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D23076 llvm-svn: 277553
2016-08-03 08:01:46 +08:00
; RUN: opt -aa-pipeline=basic-aa -passes='print<memoryssa>,verify<memoryssa>' -disable-output < %s 2>&1 | FileCheck %s
[MemorySSA] Don't treat lifetime.end as NoAlias MemorySSA currently treats lifetime.end intrinsics as not aliasing anything. This breaks MemorySSA-based MemCpyOpt, because we'll happily move a read of a pointer below a lifetime.end intrinsic, as no clobber is reported. I think the MemorySSA modelling here isn't correct: lifetime.end(p) has approximately the same effect as doing a memcpy(p, undef), and should be treated as a clobber. This patch removes the special handling of lifetime.end, leaving alias analysis to handle it appropriately. Differential Revision: https://reviews.llvm.org/D95763
2021-02-01 00:55:24 +08:00
; This test checks that lifetime markers are considered clobbers of %P,
; and due to lack of noalias information, of %Q as well.
Support for lifetime begin/end markers in the MemorySSA use optimizer Summary: Depends on D23072 Reviewers: george.burgess.iv Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D23076 llvm-svn: 277553
2016-08-03 08:01:46 +08:00
define i8 @test(i8* %P, i8* %Q) {
entry:
; CHECK: 1 = MemoryDef(liveOnEntry)
Add address space mangling to lifetime intrinsics In preparation for allowing allocas to have non-0 addrspace. llvm-svn: 299876
2017-04-11 04:18:21 +08:00
; CHECK-NEXT: call void @llvm.lifetime.start.p0i8(i64 32, i8* %P)
call void @llvm.lifetime.start.p0i8(i64 32, i8* %P)
MemorySSA: Make lifetime starts defs for mustaliased pointers Summary: While we don't want them aliasing with other pointers, there seems to be no point in not having them clobber must-aliased'd pointers. If some day, we split the aliasing and ordering chains, we'd make this not aliasing but an ordering barrier (IE it doesn't affect it's memory, but we can't hoist it above it). Reviewers: hfinkel, george.burgess.iv Subscribers: Prazek, llvm-commits Differential Revision: https://reviews.llvm.org/D31865 llvm-svn: 299865
2017-04-11 02:46:00 +08:00
; CHECK: MemoryUse(1)
Support for lifetime begin/end markers in the MemorySSA use optimizer Summary: Depends on D23072 Reviewers: george.burgess.iv Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D23076 llvm-svn: 277553
2016-08-03 08:01:46 +08:00
; CHECK-NEXT: %0 = load i8, i8* %P
%0 = load i8, i8* %P
; CHECK: 2 = MemoryDef(1)
; CHECK-NEXT: store i8 1, i8* %P
store i8 1, i8* %P
; CHECK: 3 = MemoryDef(2)
Add address space mangling to lifetime intrinsics In preparation for allowing allocas to have non-0 addrspace. llvm-svn: 299876
2017-04-11 04:18:21 +08:00
; CHECK-NEXT: call void @llvm.lifetime.end.p0i8(i64 32, i8* %P)
call void @llvm.lifetime.end.p0i8(i64 32, i8* %P)
[MemorySSA] Don't treat lifetime.end as NoAlias MemorySSA currently treats lifetime.end intrinsics as not aliasing anything. This breaks MemorySSA-based MemCpyOpt, because we'll happily move a read of a pointer below a lifetime.end intrinsic, as no clobber is reported. I think the MemorySSA modelling here isn't correct: lifetime.end(p) has approximately the same effect as doing a memcpy(p, undef), and should be treated as a clobber. This patch removes the special handling of lifetime.end, leaving alias analysis to handle it appropriately. Differential Revision: https://reviews.llvm.org/D95763
2021-02-01 00:55:24 +08:00
; CHECK: MemoryUse(3)
Support for lifetime begin/end markers in the MemorySSA use optimizer Summary: Depends on D23072 Reviewers: george.burgess.iv Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D23076 llvm-svn: 277553
2016-08-03 08:01:46 +08:00
; CHECK-NEXT: %1 = load i8, i8* %P
%1 = load i8, i8* %P
[MemorySSA] Don't treat lifetime.end as NoAlias MemorySSA currently treats lifetime.end intrinsics as not aliasing anything. This breaks MemorySSA-based MemCpyOpt, because we'll happily move a read of a pointer below a lifetime.end intrinsic, as no clobber is reported. I think the MemorySSA modelling here isn't correct: lifetime.end(p) has approximately the same effect as doing a memcpy(p, undef), and should be treated as a clobber. This patch removes the special handling of lifetime.end, leaving alias analysis to handle it appropriately. Differential Revision: https://reviews.llvm.org/D95763
2021-02-01 00:55:24 +08:00
; CHECK: MemoryUse(3)
Support for lifetime begin/end markers in the MemorySSA use optimizer Summary: Depends on D23072 Reviewers: george.burgess.iv Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D23076 llvm-svn: 277553
2016-08-03 08:01:46 +08:00
; CHECK-NEXT: %2 = load i8, i8* %Q
%2 = load i8, i8* %Q
ret i8 %1
}
Add address space mangling to lifetime intrinsics In preparation for allowing allocas to have non-0 addrspace. llvm-svn: 299876
2017-04-11 04:18:21 +08:00
declare void @llvm.lifetime.start.p0i8(i64 %S, i8* nocapture %P) readonly
declare void @llvm.lifetime.end.p0i8(i64 %S, i8* nocapture %P)