[PATCH] D76055: [SystemZ] Improve foldMemoryOperandImpl().

[Ulrich Weigand via Phabricator via llvm-commits]

uweigand added inline comments.


================
Comment at: llvm/lib/Target/SystemZ/SystemZInstrInfo.cpp:1228
+  if (SystemZ::getTwoOperandOpcode(Opcode) != -1 ||
+      Opcode == SystemZ::MSRKC || Opcode == SystemZ::MSGRKC) {
     if (VRM == nullptr)
----------------
uweigand wrote:
> I'm wondering if the should just have getTwoOperandOpcode return something for these instead.
> 
> But it's probably not worth the complication to special-case the CC handling in ShortenInst ...
Hmm.  Thinking about this some more, I think what we're really testing for here is simple: does the MemOpcode need its output and first input operand to be tied or not.  If yes, we need to verify that they can be tied (potentially via commutation).

I believe it should be possibly to simply check for that property by looking at the MCInstrDest for MemOpcode.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D76055/new/

https://reviews.llvm.org/D76055