diff options
| -rw-r--r-- | lib/CodeGen/RegisterCoalescer.cpp | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/lib/CodeGen/RegisterCoalescer.cpp b/lib/CodeGen/RegisterCoalescer.cpp index 7467bb595a..3cede9f490 100644 --- a/lib/CodeGen/RegisterCoalescer.cpp +++ b/lib/CodeGen/RegisterCoalescer.cpp @@ -166,7 +166,8 @@ namespace { /// reMaterializeTrivialDef - If the source of a copy is defined by a /// trivial computation, replace the copy by rematerialize the definition. - bool reMaterializeTrivialDef(CoalescerPair &CP, MachineInstr *CopyMI); + bool reMaterializeTrivialDef(CoalescerPair &CP, MachineInstr *CopyMI, + bool &IsDefCopy); /// canJoinPhys - Return true if a physreg copy should be joined. bool canJoinPhys(const CoalescerPair &CP); @@ -731,7 +732,9 @@ bool RegisterCoalescer::removeCopyByCommutingDef(const CoalescerPair &CP, /// reMaterializeTrivialDef - If the source of a copy is defined by a trivial /// computation, replace the copy by rematerialize the definition. bool RegisterCoalescer::reMaterializeTrivialDef(CoalescerPair &CP, - MachineInstr *CopyMI) { + MachineInstr *CopyMI, + bool &IsDefCopy) { + IsDefCopy = false; unsigned SrcReg = CP.isFlipped() ? CP.getDstReg() : CP.getSrcReg(); unsigned SrcIdx = CP.isFlipped() ? CP.getDstIdx() : CP.getSrcIdx(); unsigned DstReg = CP.isFlipped() ? CP.getSrcReg() : CP.getDstReg(); @@ -750,6 +753,10 @@ bool RegisterCoalescer::reMaterializeTrivialDef(CoalescerPair &CP, if (!DefMI) return false; assert(DefMI && "Defining instruction disappeared"); + if (DefMI->isCopyLike()) { + IsDefCopy = true; + return false; + } if (!DefMI->isAsCheapAsAMove()) return false; if (!TII->isTriviallyReMaterializable(DefMI, AA)) @@ -1064,8 +1071,11 @@ bool RegisterCoalescer::joinCopy(MachineInstr *CopyMI, bool &Again) { if (!canJoinPhys(CP)) { // Before giving up coalescing, if definition of source is defined by // trivial computation, try rematerializing it. - if (reMaterializeTrivialDef(CP, CopyMI)) + bool IsDefCopy; + if (reMaterializeTrivialDef(CP, CopyMI, IsDefCopy)) return true; + if (IsDefCopy) + Again = true; // May be possible to coalesce later. return false; } } else { @@ -1097,7 +1107,8 @@ bool RegisterCoalescer::joinCopy(MachineInstr *CopyMI, bool &Again) { // If definition of source is defined by trivial computation, try // rematerializing it. - if (reMaterializeTrivialDef(CP, CopyMI)) + bool IsDefCopy; + if (reMaterializeTrivialDef(CP, CopyMI, IsDefCopy)) return true; // If we can eliminate the copy without merging the live ranges, do so now. |