[PATCH] D133257: [GISel] Fix match tree emitter.

[Kai Nacke via Phabricator via llvm-commits]

Kai created this revision.
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The following changes are necessary to get the generated tree matcher to compile:

- In `CodeExpansions::declare()`, the `assert()` prevents connecting two instructions. E.g. the match code `(match (MUL $t, $s1, $s2), (SUB $d, $t, $s3)),` results in two declarations of `$t,` one for the def and one for the use. Removing the assertion allows this construct. If `$t` is later used, it is one of the operands, which should be perfectly fine for now.
  - The code emitted in `GIMatchTreeVRegDefPartitioner::generatePartitionSelectorCode()` is not compilable:
    - The value of `NewInstrID` should be emitted, not the name
    - Both calls involving `getOperand()` end with one parenthesis too many

With these changes, compilable code is emitted for the `TableGen/GICombinerEmitter/match-tree.td` test.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D133257

Files:
  llvm/utils/TableGen/GlobalISel/CodeExpansions.h
  llvm/utils/TableGen/GlobalISel/GIMatchTree.cpp


Index: llvm/utils/TableGen/GlobalISel/GIMatchTree.cpp
===================================================================
--- llvm/utils/TableGen/GlobalISel/GIMatchTree.cpp
+++ llvm/utils/TableGen/GlobalISel/GIMatchTree.cpp
@@ -762,13 +762,14 @@
 
 void GIMatchTreeVRegDefPartitioner::generatePartitionSelectorCode(
     raw_ostream &OS, StringRef Indent) const {
-  OS << Indent << "Partition = -1\n"
-     << Indent << "if (MIs.size() <= NewInstrID) MIs.resize(NewInstrID + 1);\n"
+  OS << Indent << "Partition = -1;\n"
+     << Indent << "if (MIs.size() <= " << NewInstrID << ") MIs.resize("
+     << (NewInstrID + 1) << ");\n"
      << Indent << "MIs[" << NewInstrID << "] = nullptr;\n"
-     << Indent << "if (MIs[" << InstrID << "].getOperand(" << OpIdx
-     << ").isReg()))\n"
+     << Indent << "if (MIs[" << InstrID << "]->getOperand(" << OpIdx
+     << ").isReg())\n"
      << Indent << "  MIs[" << NewInstrID << "] = MRI.getVRegDef(MIs[" << InstrID
-     << "].getOperand(" << OpIdx << ").getReg()));\n";
+     << "]->getOperand(" << OpIdx << ").getReg());\n";
 
   for (const auto &Pair : ResultToPartition)
     OS << Indent << "if (MIs[" << NewInstrID << "] "
Index: llvm/utils/TableGen/GlobalISel/CodeExpansions.h
===================================================================
--- llvm/utils/TableGen/GlobalISel/CodeExpansions.h
+++ llvm/utils/TableGen/GlobalISel/CodeExpansions.h
@@ -25,7 +25,8 @@
 public:
   void declare(StringRef Name, StringRef Expansion) {
     bool Inserted = Expansions.try_emplace(Name, Expansion).second;
-    assert(Inserted && "Declared variable twice");
+    // Duplicates are not inserted. The expansion refers to different operands
+    // but to the same virtual register.
     (void)Inserted;
   }
 


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