Simplifications to liveinterval analysis, no functionality change.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@29896 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp
index d094da9..0672fc6 100644
--- a/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -790,39 +790,34 @@
return false;
}
+ // Okay, we can join these two intervals. If one of the intervals being
+ // joined is a physreg, this method always canonicalizes DestInt to be it.
+ // The output "SrcInt" will not have been modified.
+ DestInt.join(SrcInt, MIDefIdx);
+
+ bool Swapped = SrcReg == DestInt.reg;
+ if (Swapped)
+ std::swap(SrcReg, DstReg);
+ assert(MRegisterInfo::isVirtualRegister(SrcReg) &&
+ "LiveInterval::join didn't work right!");
+
// If we're about to merge live ranges into a physical register live range,
// we have to update any aliased register's live ranges to indicate that they
// have clobbered values for this range.
- if (MRegisterInfo::isPhysicalRegister(SrcReg) ||
- MRegisterInfo::isPhysicalRegister(DstReg)) {
- // Figure out which register is the physical reg and which one is the
- // virtreg.
- LiveInterval *PhysRegLI = &SrcInt, *VirtRegLI = &DestInt;
- if (MRegisterInfo::isPhysicalRegister(DstReg))
- std::swap(PhysRegLI, VirtRegLI);
-
- for (const unsigned *AS = mri_->getAliasSet(PhysRegLI->reg); *AS; ++AS)
- getInterval(*AS).MergeInClobberRanges(*VirtRegLI);
+ if (MRegisterInfo::isPhysicalRegister(DstReg)) {
+ for (const unsigned *AS = mri_->getAliasSet(DstReg); *AS; ++AS)
+ getInterval(*AS).MergeInClobberRanges(SrcInt);
}
- DestInt.join(SrcInt, MIDefIdx);
- // FIXME: If SrcInt/DestInt are physregs, we must insert the new liveranges
- // into all aliasing registers as clobbers.
-
DEBUG(std::cerr << "\n\t\tJoined. Result = "; DestInt.print(std::cerr, mri_);
std::cerr << "\n");
-
- if (!MRegisterInfo::isPhysicalRegister(SrcReg)) {
- r2iMap_.erase(SrcReg);
- r2rMap_[SrcReg] = DstReg;
- } else {
- // Otherwise merge the data structures the other way so we don't lose
- // the physreg information.
- r2rMap_[DstReg] = SrcReg;
- DestInt.reg = SrcReg;
- SrcInt.swap(DestInt);
- r2iMap_.erase(DstReg);
- }
+
+ // If the intervals were swapped by Join, swap them back so that the register
+ // mapping (in the r2i map) is correct.
+ if (Swapped) SrcInt.swap(DestInt);
+ r2iMap_.erase(SrcReg);
+ r2rMap_[SrcReg] = DstReg;
+
++numJoins;
return true;
}