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MemCpyOptimizer: don't create new addrspace casts

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This isn't safe on all targets, and since we don't have a way
to know it's safe, avoid doing it for now.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297788 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Fiona Glaser 2017-03-14 22:37:38 +00:00
parent dfb7eaee7b
commit 54dc1ed088
2 changed files with 26 additions and 0 deletions
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11
lib/Transforms/Scalar/MemCpyOptimizer.cpp
View File

@ -932,6 +932,17 @@ bool MemCpyOptPass::performCallSlotOptzn(Instruction *cpy, Value *cpyDest,
if (MR != MRI_NoModRef)
return false;
// We can't create address space casts here because we don't know if they're
// safe for the target.
if (cpySrc->getType()->getPointerAddressSpace() !=
cpyDest->getType()->getPointerAddressSpace())
return false;
for (unsigned i = 0; i < CS.arg_size(); ++i)
if (CS.getArgument(i)->stripPointerCasts() == cpySrc &&
cpySrc->getType()->getPointerAddressSpace() !=
CS.getArgument(i)->getType()->getPointerAddressSpace())
return false;
// All the checks have passed, so do the transformation.
bool changedArgument = false;
for (unsigned i = 0; i < CS.arg_size(); ++i)

15
test/Transforms/MemCpyOpt/memcpy.ll
View File

@ -202,6 +202,21 @@ define void @test10(%opaque* noalias nocapture sret %x, i32 %y) {
ret void
}
; don't create new addressspacecasts when we don't know they're safe for the target
define void @test11([20 x i32] addrspace(1)* nocapture dereferenceable(80) %P) {
%A = alloca [20 x i32], align 4
%a = bitcast [20 x i32]* %A to i8*
%b = bitcast [20 x i32] addrspace(1)* %P to i8 addrspace(1)*
call void @llvm.memset.p0i8.i64(i8* %a, i8 0, i64 80, i32 4, i1 false)
call void @llvm.memcpy.p1i8.p0i8.i64(i8 addrspace(1)* %b, i8* %a, i64 80, i32 4, i1 false)
ret void
; CHECK-LABEL: @test11(
; CHECK-NOT: addrspacecast
}
declare void @llvm.memset.p0i8.i64(i8* nocapture, i8, i64, i32, i1) nounwind
declare void @llvm.memcpy.p1i8.p0i8.i64(i8 addrspace(1)* nocapture, i8* nocapture, i64, i32, i1) nounwind
declare void @f1(%struct.big* nocapture sret)
declare void @f2(%struct.big*)