diff options
| -rw-r--r-- | lib/CodeGen/RegisterCoalescer.cpp | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/lib/CodeGen/RegisterCoalescer.cpp b/lib/CodeGen/RegisterCoalescer.cpp index d5025b9e63..13ae04283a 100644 --- a/lib/CodeGen/RegisterCoalescer.cpp +++ b/lib/CodeGen/RegisterCoalescer.cpp @@ -1203,7 +1203,6 @@ static bool RegistersDefinedFromSameValue(LiveIntervals &li, VNInfo *VNI, LiveRange *LR, SmallVector<MachineInstr*, 8> &DupCopies) { - return false; // To see if this fixes the i386 dragonegg buildbot miscompile. // FIXME: This is very conservative. For example, we don't handle // physical registers. @@ -1252,6 +1251,12 @@ static bool RegistersDefinedFromSameValue(LiveIntervals &li, if (Src != OtherSrc) return false; + // If the copies use two different value numbers of X, we cannot merge + // A and B. + if (SrcInt.FindLiveRangeContaining(Other->def)->valno != + SrcInt.FindLiveRangeContaining(VNI->def)->valno) + return false; + DupCopies.push_back(MI); return true; |