Make the hasPHIKills flag a computed property.
The VNInfo::HAS_PHI_KILL is only half supported. We precompute it in
LiveIntervalAnalysis, but it isn't properly updated by live range
splitting and functions like shrinkToUses().
It is only used in one place: RegisterCoalescer::removeCopyByCommutingDef().
This patch changes that function to use a new LiveIntervals::hasPHIKill()
function that computes the flag for a given value number.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161254 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp
index 31f938e..54d6655 100644
--- a/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -780,6 +780,25 @@
return MBB1 == MBB2 ? MBB1 : NULL;
}
+bool
+LiveIntervals::hasPHIKill(const LiveInterval &LI, const VNInfo *VNI) const {
+ for (LiveInterval::const_vni_iterator I = LI.vni_begin(), E = LI.vni_end();
+ I != E; ++I) {
+ const VNInfo *PHI = *I;
+ if (PHI->isUnused() || !PHI->isPHIDef())
+ continue;
+ const MachineBasicBlock *PHIMBB = getMBBFromIndex(PHI->def);
+ // Conservatively return true instead of scanning huge predecessor lists.
+ if (PHIMBB->pred_size() > 100)
+ return true;
+ for (MachineBasicBlock::const_pred_iterator
+ PI = PHIMBB->pred_begin(), PE = PHIMBB->pred_end(); PI != PE; ++PI)
+ if (VNI == LI.getVNInfoBefore(Indexes->getMBBEndIdx(*PI)))
+ return true;
+ }
+ return false;
+}
+
float
LiveIntervals::getSpillWeight(bool isDef, bool isUse, unsigned loopDepth) {
// Limit the loop depth ridiculousness.