[PATCH] D37184: [X86] Add constant pool decoding to more instructions

[Sanjay Patel via Phabricator via llvm-commits]

spatel added a comment.

This is a good improvement, but can we make the splats even less of an eye chart (let me know if you see any problems with this):

  Index: lib/Target/X86/X86MCInstLower.cpp
  ===================================================================
  --- lib/Target/X86/X86MCInstLower.cpp (revision 327978)
  +++ lib/Target/X86/X86MCInstLower.cpp (working copy)
  @@ -1447,6 +1447,81 @@
     }
   }
  
  +static void printConstantPoolOp(MCStreamer &OutStreamer,
  +                                const MachineInstr *MI,
  +                                StringRef Op, unsigned EltSize,
  +                                bool EOL) {
  +  if (!OutStreamer.isVerboseAsm())
  +    return;
  +
  +  const MCInstrDesc &Desc = MI->getDesc();
  +  int MemOperand = X86II::getOperandBias(Desc) +
  +                   X86II::getMemoryOperandNo(Desc.TSFlags);
  +  const MachineOperand &MemOp = MI->getOperand(MemOperand + 3);
  +
  +  auto *C = getConstantFromPool(*MI, MemOp);
  +  if (!C)
  +    return;
  +
  +  SmallVector<uint64_t, 16> Vec;
  +  APInt UndefElts;
  +  if (!extractConstantMask(C, EltSize, UndefElts, Vec))
  +    return;
  +
  +  const MachineOperand &DstOp = MI->getOperand(0);
  +  const MachineOperand &SrcOp = MI->getOperand(Desc.getNumDefs());
  +
  +  std::string Comment;
  +  raw_string_ostream CS(Comment);
  +
  +  CS << X86ATTInstPrinter::getRegisterName(DstOp.getReg());
  +  CS << " = ";
  +  CS << X86ATTInstPrinter::getRegisterName(SrcOp.getReg());
  +  CS << Op << "[";
  +
  +  // Try to print the minimal splat constant. The vector constant returned by
  +  // extractConstantMask may have wider elements than the element type of the
  +  // actual mask constant.
  +  Type *CTy = C->getType();
  +  unsigned VecNumElts = Vec.size();
  +  if (CTy->isVectorTy() && CTy->getVectorNumElements() > VecNumElts) {
  +    if (auto *SplatC = dyn_cast_or_null<ConstantInt>(C->getSplatValue())) {
  +      uint64_t SplatVal = SplatC->getZExtValue();
  +      CS << format_hex(SplatVal, CTy->getScalarSizeInBits() / 4 + 2);
  +      CS << " splat]";
  +      OutStreamer.AddComment(CS.str(), EOL);
  +      return;
  +    }
  +  }
  +
  +  // Print the mask
  +  bool IsSplat = true;
  +  for (unsigned i = 1; i < VecNumElts; ++i) {
  +    if (Vec[0] != Vec[i]) {
  +      IsSplat = false;
  +      break;
  +    }
  +  }
  +
  +  for (unsigned i = 0; i < VecNumElts; ++i) {
  +    if (i != 0)
  +      CS << ",";
  +    if (UndefElts[i])
  +      CS << 'u';
  +    else
  +      CS << format_hex(Vec[i], EltSize / 4 + 2);
  +
  +    if (IsSplat) {
  +      CS << " splat";
  +      break;
  +    }
  +  }
  +
  +  CS << "]";
  +
  +  OutStreamer.AddComment(CS.str(), EOL);
  +}
  +
   void X86AsmPrinter::EmitInstruction(const MachineInstr *MI) {
     X86MCInstLower MCInstLowering(*MF, *this);
     const X86RegisterInfo *RI = MF->getSubtarget<X86Subtarget>().getRegisterInfo();


Repository:
  rL LLVM

https://reviews.llvm.org/D37184