diff options
Diffstat (limited to 'lib/CodeGen/RegAllocGreedy.cpp')
| -rw-r--r-- | lib/CodeGen/RegAllocGreedy.cpp | 18 |
1 files changed, 15 insertions, 3 deletions
diff --git a/lib/CodeGen/RegAllocGreedy.cpp b/lib/CodeGen/RegAllocGreedy.cpp index b150582da6..d57bc88a13 100644 --- a/lib/CodeGen/RegAllocGreedy.cpp +++ b/lib/CodeGen/RegAllocGreedy.cpp @@ -921,6 +921,7 @@ void RAGreedy::splitAroundRegion(LiveInterval &VirtReg, SmallVector<unsigned, 8> IntvMap; SE->finish(&IntvMap); LRStage.resize(MRI->getNumVirtRegs()); + unsigned OrigBlocks = SA->getNumThroughBlocks() + SA->getUseBlocks().size(); // Sort out the new intervals created by splitting. We get four kinds: // - Remainder intervals should not be split again. @@ -941,9 +942,20 @@ void RAGreedy::splitAroundRegion(LiveInterval &VirtReg, continue; } - // Other intervals are treated as new. This includes the main interval, - // local intervals created for blocks with multiple uses, and anything - // created by DCE. + // Main interval. Allow repeated splitting as long as the number of live + // blocks is strictly decreasing. + if (IntvMap[i] == MainIntv) { + if (SA->countLiveBlocks(LREdit.get(i)) >= OrigBlocks) { + DEBUG(dbgs() << "Main interval covers the same " << OrigBlocks + << " blocks as original.\n"); + // Don't allow repeated splitting as a safe guard against looping. + LRStage[Reg] = RS_Global; + } + continue; + } + + // Other intervals are treated as new. This includes local intervals created + // for blocks with multiple uses, and anything created by DCE. } if (VerifyEnabled) |