[llvm] [TableGen] Split large printInstruction() for NVPTX to avoid compiler limits (PR #218530)

[Kazu Hirata via llvm-commits]

================
@@ -579,29 +598,132 @@ void AsmWriterEmitter::EmitPrintInstruction(
   llvm::erase_if(Instructions,
                  [](AsmWriterInst &Inst) { return Inst.Operands.empty(); });
 
-  // Because this is a vector, we want to emit from the end.  Reverse all of the
-  // elements in the vector.
-  std::reverse(Instructions.begin(), Instructions.end());
-
-  std::vector<InstructionGroup> Groups = groupInstructions(Instructions);
-
   // Now that we've emitted all of the operand info that fit into 64 bits, emit
   // information for those instructions that are left.  This is a less dense
   // encoding, but we expect the main 64-bit table to handle the majority of
   // instructions.
-  if (!Groups.empty()) {
-    // Find the opcode # of inline asm.
-    O << "  switch (MI->getOpcode()) {\n";
-    O << "  default: llvm_unreachable(\"Unexpected opcode.\");\n";
-    for (const InstructionGroup &G : Groups)
-      emitInstructions(G, O, PassSubtarget);
+  if (!Instructions.empty()) {
+    if (UseFnPtrTable) {
+      // Single unconditional indirect call; the function-pointer table was
+      // emitted above, before printInstruction().
+      EmitOpcodePatternDispatch(O, Target.getName(), ClassName, PassSubtarget);
+    } else {
+      // Because this is a vector, we want to emit from the end.  Reverse all
+      // of the elements in the vector.
+      std::reverse(Instructions.begin(), Instructions.end());
 
-    O << "  }\n";
+      std::vector<InstructionGroup> Groups = groupInstructions(Instructions);
+
+      O << "  switch (MI->getOpcode()) {\n";
+      O << "  default: llvm_unreachable(\"Unexpected opcode.\");\n";
+      for (const InstructionGroup &G : Groups)
+        emitInstructions(G, O, PassSubtarget);
+
+      O << "  }\n";
+    }
   }
 
   O << "}\n";
 }
 
+void AsmWriterEmitter::EmitOpcodePatternTable(raw_ostream &O,
+                                              StringRef TargetName,
+                                              StringRef ClassName,
+                                              bool PassSubtarget) {
+  // Collect overflow instructions that still have operands to print.
+  std::vector<AsmWriterInst> OpcodeInsts;
+  for (const AsmWriterInst &AWI : Instructions) {
+    if (!AWI.Operands.empty())
+      OpcodeInsts.push_back(AWI);
+  }
----------------
kazutakahirata wrote:

May I suggest removing this filter loop and directly using `Instructions` in the code below?  You should be able to do so if we move up `llvm::erase_if`. (See the comment above.)

https://github.com/llvm/llvm-project/pull/218530