[llvm] [RISCV] Handle .vx/.vi pseudos in hasAllNBitUsers (PR #67419)

[Craig Topper via llvm-commits]

================
@@ -2752,6 +2752,150 @@ bool RISCVDAGToDAGISel::selectSHXADD_UWOp(SDValue N, unsigned ShAmt,
   return false;
 }
 
+static bool vectorPseudoHasAllNBitUsers(SDNode *User, unsigned UserOpNo,
+                                        unsigned Bits,
+                                        const TargetInstrInfo *TII) {
+  const RISCVVPseudosTable::PseudoInfo *PseudoInfo =
+      RISCVVPseudosTable::getPseudoInfo(User->getMachineOpcode());
+
+  if (!PseudoInfo)
+    return false;
+
+  const MCInstrDesc &MCID = TII->get(User->getMachineOpcode());
+  const uint64_t TSFlags = MCID.TSFlags;
+  if (!RISCVII::hasSEWOp(TSFlags))
+    return false;
+  assert(RISCVII::hasVLOp(TSFlags));
+
+  bool HasGlueOp = User->getGluedNode() != nullptr;
+  unsigned ChainOpIdx = User->getNumOperands() - HasGlueOp - 1;
+  bool HasChainOp = User->getOperand(ChainOpIdx).getValueType() == MVT::Other;
+  bool HasVecPolicyOp = RISCVII::hasVecPolicyOp(TSFlags);
+  unsigned VLIdx =
+      User->getNumOperands() - HasVecPolicyOp - HasChainOp - HasGlueOp - 2;
+  const unsigned Log2SEW = User->getConstantOperandVal(VLIdx + 1);
+
+  if (UserOpNo == VLIdx)
+    return false;
+
+  // TODO: Handle Zvbb instructions
+  switch (PseudoInfo->BaseInstr) {
+  default:
+    return false;
+
+  // 11.6. Vector Single-Width Shift Instructions
+  case RISCV::VSLL_VX:
+  case RISCV::VSRL_VX:
+  case RISCV::VSRA_VX:
+  // 12.4. Vector Single-Width Scaling Shift Instructions
+  case RISCV::VSSRL_VX:
+  case RISCV::VSSRA_VX:
+    // Only the low lg2(SEW) bits of the shift-amount value are used.
+    if (Bits < Log2SEW)
+      return false;
+    break;
+
+  // 11.7 Vector Narrowing Integer Right Shift Instructions
+  case RISCV::VNSRL_WX:
+  case RISCV::VNSRA_WX:
+  // 12.5. Vector Narrowing Fixed-Point Clip Instructions
+  case RISCV::VNCLIPU_WX:
+  case RISCV::VNCLIP_WX:
+    // Only the low lg2(2*SEW) bits of the shift-amount value are used.
+    if (Bits < Log2SEW + 1)
+      return false;
+    break;
+
+  // 11.1. Vector Single-Width Integer Add and Subtract
+  case RISCV::VADD_VX:
+  case RISCV::VSUB_VX:
+  case RISCV::VRSUB_VX:
+  // 11.2. Vector Widening Integer Add/Subtract
+  case RISCV::VWADDU_VX:
+  case RISCV::VWSUBU_VX:
+  case RISCV::VWADD_VX:
+  case RISCV::VWSUB_VX:
+  case RISCV::VWADDU_WX:
+  case RISCV::VWSUBU_WX:
+  case RISCV::VWADD_WX:
+  case RISCV::VWSUB_WX:
+  // 11.4. Vector Integer Add-with-Carry / Subtract-with-Borrow Instructions
+  case RISCV::VADC_VXM:
+  case RISCV::VADC_VIM:
+  case RISCV::VMADC_VXM:
+  case RISCV::VMADC_VIM:
----------------
topperc wrote:

I think you can drop VIM?

https://github.com/llvm/llvm-project/pull/67419