diff options
Diffstat (limited to 'llvm/lib/CodeGen/RegisterCoalescer.cpp')
| -rw-r--r-- | llvm/lib/CodeGen/RegisterCoalescer.cpp | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/RegisterCoalescer.cpp b/llvm/lib/CodeGen/RegisterCoalescer.cpp index 990ef370bb3..361ae7a63f0 100644 --- a/llvm/lib/CodeGen/RegisterCoalescer.cpp +++ b/llvm/lib/CodeGen/RegisterCoalescer.cpp @@ -967,6 +967,14 @@ RegisterCoalescer::UpdateRegDefsUses(const CoalescerPair &CP) { Kills |= MO.isKill(); Deads |= MO.isDead(); + // Make sure we don't create read-modify-write defs accidentally. We + // assume here that a SrcReg def cannot be joined into a live DstReg. If + // RegisterCoalescer starts tracking partially live registers, we will + // need to check the actual LiveInterval to determine if DstReg is live + // here. + if (SubIdx && !Reads) + MO.setIsUndef(); + if (DstIsPhys) MO.substPhysReg(DstReg, *TRI); else |
