6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2025-10-25 10:27:04 +00:00
Code Issues Projects Releases Wiki Activity

Allow call-slop optzn for destinations with a suitable dereferenceable attribute

Browse Source 
Summary:
Currently, call slot optimization requires that if the destination is an
argument, the argument has the sret attribute. This is to ensure that
the memory access won't trap. In addition to sret, we can also allow the
optimization to happen for arguments that have the new dereferenceable
attribute, which gives the same guarantee.

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D5832

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219950 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Bjorn Steinbrink
2014-10-16 19:43:08 +00:00
parent 0ab5b9f647
commit 6eaa62af77
2 changed files with 45 additions and 14 deletions
Download Patch File Download Diff File Expand all files Collapse all files

30
lib/Transforms/Scalar/MemCpyOptimizer.cpp
View File

@@ -634,22 +634,24 @@ bool MemCpyOpt::performCallSlotOptzn(Instruction *cpy,
if (destSize < srcSize)
return false;
} else if (Argument *A = dyn_cast<Argument>(cpyDest)) {
// If the destination is an sret parameter then only accesses that are
// outside of the returned struct type can trap.
if (!A->hasStructRetAttr())
return false;
if (A->getDereferenceableBytes() < srcSize) {
// If the destination is an sret parameter then only accesses that are
// outside of the returned struct type can trap.
if (!A->hasStructRetAttr())
return false;
Type *StructTy = cast<PointerType>(A->getType())->getElementType();
if (!StructTy->isSized()) {
// The call may never return and hence the copy-instruction may never
// be executed, and therefore it's not safe to say "the destination
// has at least <cpyLen> bytes, as implied by the copy-instruction",
return false;
Type *StructTy = cast<PointerType>(A->getType())->getElementType();
if (!StructTy->isSized()) {
// The call may never return and hence the copy-instruction may never
// be executed, and therefore it's not safe to say "the destination
// has at least <cpyLen> bytes, as implied by the copy-instruction",
return false;
}
uint64_t destSize = DL->getTypeAllocSize(StructTy);
if (destSize < srcSize)
return false;
}
uint64_t destSize = DL->getTypeAllocSize(StructTy);
if (destSize < srcSize)
return false;
} else {
return false;
}