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Treat sret arguments as being dereferenceable in getPointerDereferenceableBytes() 

Reviewers: rnk, hfinkel, efriedma

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D41355

llvm-svn: 321061
This commit is contained in:
Bjorn Steinbrink 2017-12-19 08:46:46 +00:00
parent e21475e54a
commit 2da4d9d86d
2 changed files with 14 additions and 3 deletions
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5
llvm/lib/IR/Value.cpp
View File

@ -627,9 +627,10 @@ uint64_t Value::getPointerDereferenceableBytes(const DataLayout &DL,
CanBeNull = false;
if (const Argument *A = dyn_cast<Argument>(this)) {
DerefBytes = A->getDereferenceableBytes();
if (DerefBytes == 0 && A->hasByValAttr()) {
if (DerefBytes == 0 && (A->hasByValAttr() || A->hasStructRetAttr())) {
Type *PT = cast<PointerType>(A->getType())->getElementType();
DerefBytes = DL.getTypeStoreSize(PT);
if (PT->isSized())
DerefBytes = DL.getTypeStoreSize(PT);
}
if (DerefBytes == 0) {
DerefBytes = A->getDereferenceableOrNullBytes();

12
llvm/test/Analysis/ValueTracking/memory-dereferenceable.ll
View File

@ -20,7 +20,8 @@ declare i32* @foo()
@globalptr.align16 = external global i8, align 16
; CHECK-LABEL: 'test'
define void @test(i32 addrspace(1)* dereferenceable(8) %dparam,
define void @test(%struct.A* sret %result,
i32 addrspace(1)* dereferenceable(8) %dparam,
i8 addrspace(1)* dereferenceable(32) align 1 %dparam.align1,
i8 addrspace(1)* dereferenceable(32) align 16 %dparam.align16,
i8* byval %i8_byval,
@ -53,6 +54,15 @@ entry:
%baa_cast = bitcast i8* %big_array_alloca to i32*
%baa_load = load i32, i32* %baa_cast
; Loads from sret arguments
; CHECK: %sret_gep{{.*}}(aligned)
%sret_gep = getelementptr inbounds %struct.A, %struct.A* %result, i64 0, i32 1, i64 2
load i8, i8* %sret_gep
; CHECK-NOT: %sret_gep_outside
%sret_gep_outside = getelementptr %struct.A, %struct.A* %result, i64 0, i32 1, i64 7
load i8, i8* %sret_gep_outside
; CHECK: %dparam{{.*}}(aligned)
%load3 = load i32, i32 addrspace(1)* %dparam