From 1ab2b49e6d5a2cf417c7b8b0c9cfebf8e6cbc544 Mon Sep 17 00:00:00 2001 From: Lang Hames Date: Wed, 9 Dec 2009 05:39:12 +0000 Subject: Added a new "splitting" spiller. When a call is placed to spill an interval this spiller will first try to break the interval up into its component values. Single value intervals and intervals which have already been split (or are the result of previous splits) are spilled by the default spiller. Splitting intervals as described above may improve the performance of generated code in some circumstances. This work is experimental however, and it still miscompiles many benchmarks. It's not recommended for general use yet. llvm-svn: 90951 --- llvm/lib/CodeGen/RegAllocLinearScan.cpp | 15 ++++++--------- 1 file changed, 6 insertions(+), 9 deletions(-) (limited to 'llvm/lib/CodeGen/RegAllocLinearScan.cpp') diff --git a/llvm/lib/CodeGen/RegAllocLinearScan.cpp b/llvm/lib/CodeGen/RegAllocLinearScan.cpp index 4ff512932f8..c1f587567e8 100644 --- a/llvm/lib/CodeGen/RegAllocLinearScan.cpp +++ b/llvm/lib/CodeGen/RegAllocLinearScan.cpp @@ -1261,9 +1261,9 @@ void RALinScan::assignRegOrStackSlotAtInterval(LiveInterval* cur) { // The earliest start of a Spilled interval indicates up to where // in handled we need to roll back + assert(!spillIs.empty() && "No spill intervals?"); + SlotIndex earliestStart = spillIs[0]->beginIndex(); - LiveInterval *earliestStartInterval = cur; - // Spill live intervals of virtual regs mapped to the physical register we // want to clear (and its aliases). We only spill those that overlap with the // current interval as the rest do not affect its allocation. we also keep @@ -1274,19 +1274,16 @@ void RALinScan::assignRegOrStackSlotAtInterval(LiveInterval* cur) { LiveInterval *sli = spillIs.back(); spillIs.pop_back(); DEBUG(errs() << "\t\t\tspilling(a): " << *sli << '\n'); - earliestStartInterval = - (earliestStartInterval->beginIndex() < sli->beginIndex()) ? - earliestStartInterval : sli; + if (sli->beginIndex() < earliestStart) + earliestStart = sli->beginIndex(); std::vector newIs; - newIs = spiller_->spill(sli, spillIs); + newIs = spiller_->spill(sli, spillIs, &earliestStart); addStackInterval(sli, ls_, li_, mri_, *vrm_); std::copy(newIs.begin(), newIs.end(), std::back_inserter(added)); spilled.insert(sli->reg); } - SlotIndex earliestStart = earliestStartInterval->beginIndex(); - DEBUG(errs() << "\t\trolling back to: " << earliestStart << '\n'); // Scan handled in reverse order up to the earliest start of a @@ -1295,7 +1292,7 @@ void RALinScan::assignRegOrStackSlotAtInterval(LiveInterval* cur) { while (!handled_.empty()) { LiveInterval* i = handled_.back(); // If this interval starts before t we are done. - if (i->beginIndex() < earliestStart) + if (!i->empty() && i->beginIndex() < earliestStart) break; DEBUG(errs() << "\t\t\tundo changes for: " << *i << '\n'); handled_.pop_back(); -- cgit v1.2.3