[llvm] [TableGen][GISel] Reuse `importNodeRenderer` for `OperandWithDefaultOps` (PR #121285)

[Sergei Barannikov via llvm-commits]

https://github.com/s-barannikov updated https://github.com/llvm/llvm-project/pull/121285

>From cd5435e97982a34604816a90a50969a5e2aa31d2 Mon Sep 17 00:00:00 2001
From: Sergei Barannikov <barannikov88 at gmail.com>
Date: Sun, 29 Dec 2024 10:35:06 +0300
Subject: [PATCH] [TableGen][GISel] Reuse `importNodeRenderer` for
 `OperandWithDefaultOps`

This avoids some code duplication (handling `Register`, `zero_reg` and
immediate operands).
---
 llvm/utils/TableGen/GlobalISelEmitter.cpp | 77 +++++++----------------
 1 file changed, 24 insertions(+), 53 deletions(-)

diff --git a/llvm/utils/TableGen/GlobalISelEmitter.cpp b/llvm/utils/TableGen/GlobalISelEmitter.cpp
index 092cdd4ad5b435..9f244ca804a08c 100644
--- a/llvm/utils/TableGen/GlobalISelEmitter.cpp
+++ b/llvm/utils/TableGen/GlobalISelEmitter.cpp
@@ -418,7 +418,8 @@ class GlobalISelEmitter final : public GlobalISelMatchTableExecutorEmitter {
                                 const TreePatternNode &N) const;
 
   Error importLeafNodeRenderer(RuleMatcher &M, BuildMIAction &MIBuilder,
-                               const TreePatternNode &N) const;
+                               const TreePatternNode &N,
+                               action_iterator InsertPt) const;
 
   Error importXFormNodeRenderer(RuleMatcher &M, BuildMIAction &MIBuilder,
                                 const TreePatternNode &N) const;
@@ -431,9 +432,6 @@ class GlobalISelEmitter final : public GlobalISelMatchTableExecutorEmitter {
                            const TreePatternNode &N,
                            action_iterator &InsertPt) const;
 
-  Error importDefaultOperandRenderers(action_iterator InsertPt, RuleMatcher &M,
-                                      BuildMIAction &DstMIBuilder,
-                                      const DAGDefaultOperand &DefaultOp) const;
   Error importImplicitDefRenderers(BuildMIAction &DstMIBuilder,
                                    ArrayRef<const Record *> ImplicitDefs) const;
 
@@ -1291,7 +1289,8 @@ Error GlobalISelEmitter::importNamedNodeRenderer(
 
 // Equivalent of MatcherGen::EmitResultLeafAsOperand.
 Error GlobalISelEmitter::importLeafNodeRenderer(
-    RuleMatcher &M, BuildMIAction &MIBuilder, const TreePatternNode &N) const {
+    RuleMatcher &M, BuildMIAction &MIBuilder, const TreePatternNode &N,
+    action_iterator InsertPt) const {
   if (const auto *II = dyn_cast<IntInit>(N.getLeafValue())) {
     MIBuilder.addRenderer<ImmRenderer>(II->getValue());
     return Error::success();
@@ -1300,11 +1299,24 @@ Error GlobalISelEmitter::importLeafNodeRenderer(
   if (const auto *DI = dyn_cast<DefInit>(N.getLeafValue())) {
     const Record *R = DI->getDef();
 
-    if (R->isSubClassOf("Register")) {
+    if (R->isSubClassOf("Register") || R->getName() == "zero_reg") {
       MIBuilder.addRenderer<AddRegisterRenderer>(Target, R);
       return Error::success();
     }
 
+    if (R->getName() == "undef_tied_input") {
+      std::optional<LLTCodeGen> OpTyOrNone = MVTToLLT(N.getSimpleType(0));
+      unsigned TempRegID = M.allocateTempRegID();
+      M.insertAction<MakeTempRegisterAction>(InsertPt, *OpTyOrNone, TempRegID);
+      auto I = M.insertAction<BuildMIAction>(
+          InsertPt, M.allocateOutputInsnID(),
+          &Target.getInstruction(RK.getDef("IMPLICIT_DEF")));
+      auto &ImpDefBuilder = static_cast<BuildMIAction &>(**I);
+      ImpDefBuilder.addRenderer<TempRegRenderer>(TempRegID, /*IsDef=*/true);
+      MIBuilder.addRenderer<TempRegRenderer>(TempRegID);
+      return Error::success();
+    }
+
     if (R->isSubClassOf("SubRegIndex")) {
       const CodeGenSubRegIndex *SubRegIndex = CGRegs.getSubRegIdx(R);
       MIBuilder.addRenderer<ImmRenderer>(SubRegIndex->EnumValue);
@@ -1386,7 +1398,7 @@ Error GlobalISelEmitter::importNodeRenderer(RuleMatcher &M,
     return importNamedNodeRenderer(M, MIBuilder, N);
 
   if (N.isLeaf())
-    return importLeafNodeRenderer(M, MIBuilder, N);
+    return importLeafNodeRenderer(M, MIBuilder, N, InsertPt);
 
   if (N.getOperator()->isSubClassOf("SDNodeXForm"))
     return importXFormNodeRenderer(M, MIBuilder, N);
@@ -1707,11 +1719,11 @@ Expected<action_iterator> GlobalISelEmitter::importExplicitUseRenderers(
       // This is a predicate or optional def operand which the pattern has not
       // overridden, or which we aren't letting it override; emit the 'default
       // ops' operands.
-
-      const Record *OperandNode = DstI->Operands[InstOpNo].Rec;
-      if (auto Error = importDefaultOperandRenderers(
-              InsertPt, M, DstMIBuilder, CGP.getDefaultOperand(OperandNode)))
-        return std::move(Error);
+      for (const TreePatternNode &OpNode :
+           make_pointee_range(CGP.getDefaultOperand(OperandNode).DefaultOps)) {
+        if (Error Err = importNodeRenderer(M, DstMIBuilder, OpNode, InsertPt))
+          return Err;
+      }
 
       ++NumDefaultOps;
       continue;
@@ -1734,47 +1746,6 @@ Expected<action_iterator> GlobalISelEmitter::importExplicitUseRenderers(
   return InsertPt;
 }
 
-Error GlobalISelEmitter::importDefaultOperandRenderers(
-    action_iterator InsertPt, RuleMatcher &M, BuildMIAction &DstMIBuilder,
-    const DAGDefaultOperand &DefaultOp) const {
-  for (const auto &Op : DefaultOp.DefaultOps) {
-    const auto &N = *Op;
-    if (!N.isLeaf())
-      return failedImport("Could not add default op");
-
-    const auto *DefaultOp = N.getLeafValue();
-
-    if (const DefInit *DefaultDefOp = dyn_cast<DefInit>(DefaultOp)) {
-      std::optional<LLTCodeGen> OpTyOrNone = MVTToLLT(N.getSimpleType(0));
-      auto *Def = DefaultDefOp->getDef();
-      if (Def->getName() == "undef_tied_input") {
-        unsigned TempRegID = M.allocateTempRegID();
-        M.insertAction<MakeTempRegisterAction>(InsertPt, *OpTyOrNone,
-                                               TempRegID);
-        InsertPt = M.insertAction<BuildMIAction>(
-            InsertPt, M.allocateOutputInsnID(),
-            &Target.getInstruction(RK.getDef("IMPLICIT_DEF")));
-        BuildMIAction &IDMIBuilder =
-            *static_cast<BuildMIAction *>(InsertPt->get());
-        IDMIBuilder.addRenderer<TempRegRenderer>(TempRegID, /*IsDef=*/true);
-        DstMIBuilder.addRenderer<TempRegRenderer>(TempRegID);
-      } else {
-        DstMIBuilder.addRenderer<AddRegisterRenderer>(Target, Def);
-      }
-      continue;
-    }
-
-    if (const IntInit *DefaultIntOp = dyn_cast<IntInit>(DefaultOp)) {
-      DstMIBuilder.addRenderer<ImmRenderer>(DefaultIntOp->getValue());
-      continue;
-    }
-
-    return failedImport("Could not add default op");
-  }
-
-  return Error::success();
-}
-
 Error GlobalISelEmitter::importImplicitDefRenderers(
     BuildMIAction &DstMIBuilder, ArrayRef<const Record *> ImplicitDefs) const {
   if (!ImplicitDefs.empty())