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/LiveInterval.cpp b/lib/CodeGen/LiveInterval.cpp
index 80c050f..7f16b31 100644
--- a/lib/CodeGen/LiveInterval.cpp
+++ b/lib/CodeGen/LiveInterval.cpp
@@ -374,21 +374,25 @@
/// is the result of a copy instruction in the source program, that occurs at
/// index 'CopyIdx' that copies from 'Other' to 'this'.
void LiveInterval::join(LiveInterval &Other, unsigned CopyIdx) {
- const LiveRange *SourceLR = Other.getLiveRangeContaining(CopyIdx-1);
- const LiveRange *DestLR = getLiveRangeContaining(CopyIdx);
- assert(SourceLR && DestLR && "Not joining due to a copy?");
- unsigned MergedSrcValIdx = SourceLR->ValId;
- unsigned MergedDstValIdx = DestLR->ValId;
-
// Try to do the least amount of work possible. In particular, if there are
// more liverange chunks in the other set than there are in the 'this' set,
// swap sets to merge the fewest chunks in possible.
- if (Other.ranges.size() > ranges.size()) {
- std::swap(MergedSrcValIdx, MergedDstValIdx);
- std::swap(ranges, Other.ranges);
- std::swap(NumValues, Other.NumValues);
- std::swap(InstDefiningValue, Other.InstDefiningValue);
+ //
+ // Also, if one range is a physreg and one is a vreg, we always merge from the
+ // vreg into the physreg, which leaves the vreg intervals pristine.
+ unsigned OtherOffs = 1, ThisOffs = 0;
+ if ((Other.ranges.size() > ranges.size() &&
+ MRegisterInfo::isVirtualRegister(reg)) ||
+ MRegisterInfo::isPhysicalRegister(Other.reg)) {
+ swap(Other);
+ std::swap(ThisOffs, OtherOffs);
}
+
+ const LiveRange *SourceLR = Other.getLiveRangeContaining(CopyIdx-OtherOffs);
+ const LiveRange *DestLR = getLiveRangeContaining(CopyIdx-ThisOffs);
+ assert(SourceLR && DestLR && "Not joining due to a copy?");
+ unsigned MergedSrcValIdx = SourceLR->ValId;
+ unsigned MergedDstValIdx = DestLR->ValId;
// Join the ranges of other into the ranges of this interval.
std::map<unsigned, unsigned> Dst2SrcIdxMap;