6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-12-14 11:32:34 +00:00
Code Issues Projects Releases Wiki Activity

Handle register masks in local live range splitting.

Browse Source 
Again the goal is to produce identical assembly with register mask
operands enabled.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150287 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakob Stoklund Olesen 2012-02-11 00:42:18 +00:00
parent fd3d4cf0ef
commit a6d513f474
1 changed files with 25 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
lib/CodeGen/RegAllocGreedy.cpp
View File

@ -1352,6 +1352,26 @@ unsigned RAGreedy::tryLocalSplit(LiveInterval &VirtReg, AllocationOrder &Order,
dbgs() << '\n';
});
// If VirtReg is live across any register mask operands, compute a list of
// gaps with register masks.
SmallVector<unsigned, 8> RegMaskGaps;
if (!UsableRegs.empty()) {
// Get regmask slots for the whole block.
ArrayRef<SlotIndex> RMS = LIS->getRegMaskSlotsInBlock(BI.MBB->getNumber());
// Constrain to VirtReg's live range.
unsigned ri = std::lower_bound(RMS.begin(), RMS.end(), Uses.front())
- RMS.begin();
unsigned re = RMS.size();
for (unsigned i = 0; i != NumGaps && ri != re; ++i) {
assert(Uses[i] <= RMS[ri]);
if (Uses[i+1] <= RMS[ri])
continue;
RegMaskGaps.push_back(i);
do ++ri;
while (ri != re && RMS[ri] < Uses[i+1]);
}
}
// Since we allow local split results to be split again, there is a risk of
// creating infinite loops. It is tempting to require that the new live
// ranges have less instructions than the original. That would guarantee
@ -1386,6 +1406,11 @@ unsigned RAGreedy::tryLocalSplit(LiveInterval &VirtReg, AllocationOrder &Order,
// order to make use of PhysReg between UseSlots[i] and UseSlots[i+1].
calcGapWeights(PhysReg, GapWeight);
// Remove any gaps with regmask clobbers.
if (clobberedByRegMask(PhysReg))
for (unsigned i = 0, e = RegMaskGaps.size(); i != e; ++i)
GapWeight[RegMaskGaps[i]] = HUGE_VALF;
// Try to find the best sequence of gaps to close.
// The new spill weight must be larger than any gap interference.