[llvm] [SPIR-V] Move ASSIGN_TYPE generation to PostLegalizer (PR #169696)

[Nathan Gauër via llvm-commits]

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@@ -425,52 +425,21 @@ static void setInsertPtAfterDef(MachineIRBuilder &MIB, MachineInstr *Def) {
 }
 
 namespace llvm {
-void insertAssignInstr(Register Reg, Type *Ty, SPIRVType *SpvType,
-                       SPIRVGlobalRegistry *GR, MachineIRBuilder &MIB,
-                       MachineRegisterInfo &MRI) {
+void updateRegType(Register Reg, Type *Ty, SPIRVType *SpvType,
+                   SPIRVGlobalRegistry *GR, MachineIRBuilder &MIB,
+                   MachineRegisterInfo &MRI) {
   assert((Ty || SpvType) && "Either LLVM or SPIRV type is expected.");
   MachineInstr *Def = MRI.getVRegDef(Reg);
   setInsertPtAfterDef(MIB, Def);
   if (!SpvType)
     SpvType = GR->getOrCreateSPIRVType(Ty, MIB,
                                        SPIRV::AccessQualifier::ReadWrite, true);
-
-  if (!isTypeFoldingSupported(Def->getOpcode())) {
-    // No need to generate SPIRV::ASSIGN_TYPE pseudo-instruction
-    if (!MRI.getRegClassOrNull(Reg))
-      MRI.setRegClass(Reg, GR->getRegClass(SpvType));
-    if (!MRI.getType(Reg).isValid())
-      MRI.setType(Reg, GR->getRegType(SpvType));
-    GR->assignSPIRVTypeToVReg(SpvType, Reg, MIB.getMF());
-    return;
-  }
-
-  // Tablegen definition assumes SPIRV::ASSIGN_TYPE pseudo-instruction is
-  // present after each auto-folded instruction to take a type reference from.
-  Register NewReg = MRI.createGenericVirtualRegister(MRI.getType(Reg));
-  const auto *RegClass = GR->getRegClass(SpvType);
-  MRI.setRegClass(NewReg, RegClass);
-  MRI.setRegClass(Reg, RegClass);
-
+  if (!MRI.getRegClassOrNull(Reg))
+    MRI.setRegClass(Reg, GR->getRegClass(SpvType));
+  if (!MRI.getType(Reg).isValid())
+    MRI.setType(Reg, GR->getRegType(SpvType));
   GR->assignSPIRVTypeToVReg(SpvType, Reg, MIB.getMF());
-  // This is to make it convenient for Legalizer to get the SPIRVType
-  // when processing the actual MI (i.e. not pseudo one).
-  GR->assignSPIRVTypeToVReg(SpvType, NewReg, MIB.getMF());
-  // Copy MIFlags from Def to ASSIGN_TYPE instruction. It's required to keep
-  // the flags after instruction selection.
-  const uint32_t Flags = Def->getFlags();
-  MIB.buildInstr(SPIRV::ASSIGN_TYPE)
-      .addDef(Reg)
-      .addUse(NewReg)
-      .addUse(GR->getSPIRVTypeID(SpvType))
-      .setMIFlags(Flags);
-  for (unsigned I = 0, E = Def->getNumDefs(); I != E; ++I) {
-    MachineOperand &MO = Def->getOperand(I);
-    if (MO.getReg() == Reg) {
-      MO.setReg(NewReg);
-      break;
-    }
-  }
+  return;
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Keenuts wrote:

remove

https://github.com/llvm/llvm-project/pull/169696