diff options
Diffstat (limited to 'llvm/lib/CodeGen/MachineCopyPropagation.cpp')
| -rw-r--r-- | llvm/lib/CodeGen/MachineCopyPropagation.cpp | 19 |
1 files changed, 13 insertions, 6 deletions
diff --git a/llvm/lib/CodeGen/MachineCopyPropagation.cpp b/llvm/lib/CodeGen/MachineCopyPropagation.cpp index 8718245..970659c 100644 --- a/llvm/lib/CodeGen/MachineCopyPropagation.cpp +++ b/llvm/lib/CodeGen/MachineCopyPropagation.cpp @@ -595,12 +595,15 @@ void MachineCopyPropagation::forwardUses(MachineInstr &MI) { const MachineOperand &CopySrc = *CopyOperands->Source; Register CopySrcReg = CopySrc.getReg(); - // FIXME: Don't handle partial uses of wider COPYs yet. + // When the use is a subregister of the COPY destination, + // record the subreg index. + unsigned SubregIdx = 0; + + // This can only occur when we are dealing with physical registers. if (MOUse.getReg() != CopyDstReg) { - LLVM_DEBUG( - dbgs() << "MCP: FIXME! Not forwarding COPY to sub-register use:\n " - << MI); - continue; + SubregIdx = TRI->getSubRegIndex(CopyDstReg, MOUse.getReg()); + if (!SubregIdx) + continue; } // Don't forward COPYs of reserved regs unless they are constant. @@ -633,7 +636,11 @@ void MachineCopyPropagation::forwardUses(MachineInstr &MI) { << "\n with " << printReg(CopySrcReg, TRI) << "\n in " << MI << " from " << *Copy); - MOUse.setReg(CopySrcReg); + if (SubregIdx) + MOUse.setReg(TRI->getSubReg(CopySrcReg, SubregIdx)); + else + MOUse.setReg(CopySrcReg); + if (!CopySrc.isRenamable()) MOUse.setIsRenamable(false); MOUse.setIsUndef(CopySrc.isUndef()); |