[TargetInstrInfo] Let findCommutedOpIndices take const MachineInstr&

Neither the base implementation of findCommutedOpIndices nor any in-tree target modifies the instruction passed in and there is no reason why they would in the future.

Committed on behalf of @hvdijk (Harald van Dijk)

Differential Revision: https://reviews.llvm.org/D66138

llvm-svn: 372882

1 files changed, 2 insertions, 1 deletions

diff --git a/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp b/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
index c97bb4cd093..a504aeafe40 100644
--- a/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
+++ b/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
@@ -1663,7 +1663,8 @@ MachineInstr *SIInstrInfo::commuteInstructionImpl(MachineInstr &MI, bool NewMI,
 // This needs to be implemented because the source modifiers may be inserted
 // between the true commutable operands, and the base
 // TargetInstrInfo::commuteInstruction uses it.
-bool SIInstrInfo::findCommutedOpIndices(MachineInstr &MI, unsigned &SrcOpIdx0,
+bool SIInstrInfo::findCommutedOpIndices(const MachineInstr &MI,
+                                        unsigned &SrcOpIdx0,
                                         unsigned &SrcOpIdx1) const {
   return findCommutedOpIndices(MI.getDesc(), SrcOpIdx0, SrcOpIdx1);
 }