[SelectionDAG] Add space-optimized forms of OPC_CheckComplexPat

[wangpc-pp]

We record the usage of each ComplexPat and sort the ComplexPats
by usage.

For the top 8 ComplexPats, we will emit a OPC_CheckComplexPatN
to save one byte.

Overall this reduces the llc binary size with all in-tree targets by
about 89K.

[llvmbot]

@llvm/pr-subscribers-llvm-selectiondag

Author: Wang Pengcheng (wangpc-pp)

Changes

We record the usage of each ComplexPat and sort the ComplexPats
by usage.

For the top 8 ComplexPats, we will emit a OPC_CheckComplexPatN
to save one byte.

Overall this reduces the llc binary size with all in-tree targets by
about 89K.

---

Full diff: https://github.com/llvm/llvm-project/pull/73310.diff

7 Files Affected:

• (modified) llvm/include/llvm/CodeGen/SelectionDAGISel.h (+8)
• (modified) llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp (+12-2)
• (modified) llvm/test/TableGen/dag-isel-complexpattern.td (+1-1)
• (modified) llvm/utils/TableGen/CodeGenDAGPatterns.h (+12)
• (modified) llvm/utils/TableGen/DAGISelMatcher.h (+1-1)
• (modified) llvm/utils/TableGen/DAGISelMatcherEmitter.cpp (+18-11)
• (modified) llvm/utils/TableGen/DAGISelMatcherGen.cpp (+5-4)

diff --git a/llvm/include/llvm/CodeGen/SelectionDAGISel.h b/llvm/include/llvm/CodeGen/SelectionDAGISel.h
index e6513eb6abc8749..fd9857159d014e3 100644
--- a/llvm/include/llvm/CodeGen/SelectionDAGISel.h
+++ b/llvm/include/llvm/CodeGen/SelectionDAGISel.h
@@ -176,6 +176,14 @@ class SelectionDAGISel : public MachineFunctionPass {
     OPC_CheckChild2CondCode,
     OPC_CheckValueType,
     OPC_CheckComplexPat,
+    OPC_CheckComplexPat0,
+    OPC_CheckComplexPat1,
+    OPC_CheckComplexPat2,
+    OPC_CheckComplexPat3,
+    OPC_CheckComplexPat4,
+    OPC_CheckComplexPat5,
+    OPC_CheckComplexPat6,
+    OPC_CheckComplexPat7,
     OPC_CheckAndImm,
     OPC_CheckOrImm,
     OPC_CheckImmAllOnesV,
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index 7d9bebdca127224..22ca68e24600fb7 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -3279,8 +3279,18 @@ void SelectionDAGISel::SelectCodeCommon(SDNode *NodeToMatch,
         break;
       continue;
     }
-    case OPC_CheckComplexPat: {
-      unsigned CPNum = MatcherTable[MatcherIndex++];
+    case OPC_CheckComplexPat:
+    case OPC_CheckComplexPat0:
+    case OPC_CheckComplexPat1:
+    case OPC_CheckComplexPat2:
+    case OPC_CheckComplexPat3:
+    case OPC_CheckComplexPat4:
+    case OPC_CheckComplexPat5:
+    case OPC_CheckComplexPat6:
+    case OPC_CheckComplexPat7: {
+      unsigned CPNum = Opcode == OPC_CheckComplexPat
+                           ? MatcherTable[MatcherIndex++]
+                           : Opcode - OPC_CheckComplexPat0;
       unsigned RecNo = MatcherTable[MatcherIndex++];
       assert(RecNo < RecordedNodes.size() && "Invalid CheckComplexPat");
 
diff --git a/llvm/test/TableGen/dag-isel-complexpattern.td b/llvm/test/TableGen/dag-isel-complexpattern.td
index 40fd03cc8839424..1bb473a9df5a954 100644
--- a/llvm/test/TableGen/dag-isel-complexpattern.td
+++ b/llvm/test/TableGen/dag-isel-complexpattern.td
@@ -22,7 +22,7 @@ def CP32 : ComplexPattern<i32, 0, "SelectCP32">;
 def INSTR : Instruction {
 // CHECK-LABEL: OPC_CheckOpcode, TARGET_VAL(ISD::STORE)
 // CHECK: OPC_CheckType, MVT::i32
-// CHECK: OPC_CheckComplexPat, /*CP*/0, /*#*/1, // SelectCP32:$
+// CHECK: OPC_CheckComplexPat0, /*#*/1, // SelectCP32:$
 // CHECK: Src: (st (add:{ *:[i32] } (CP32:{ *:[i32] }), (CP32:{ *:[i32] })), i64:{ *:[i64] }:$addr)
   let OutOperandList = (outs);
   let InOperandList = (ins GPR64:$addr);
diff --git a/llvm/utils/TableGen/CodeGenDAGPatterns.h b/llvm/utils/TableGen/CodeGenDAGPatterns.h
index 2611fe06f55ca53..f856f007b1f45d6 100644
--- a/llvm/utils/TableGen/CodeGenDAGPatterns.h
+++ b/llvm/utils/TableGen/CodeGenDAGPatterns.h
@@ -1117,6 +1117,9 @@ class CodeGenDAGPatterns {
   std::map<Record*, DAGDefaultOperand, LessRecordByID> DefaultOperands;
   std::map<Record*, DAGInstruction, LessRecordByID> Instructions;
 
+  /// ComplexPatternUsage - Record the usage of ComplexPattern.
+  std::map<const ComplexPattern *, unsigned> ComplexPatternUsage;
+
   // Specific SDNode definitions:
   Record *intrinsic_void_sdnode;
   Record *intrinsic_w_chain_sdnode, *intrinsic_wo_chain_sdnode;
@@ -1163,6 +1166,15 @@ class CodeGenDAGPatterns {
     return F->second;
   }
 
+  const std::map<const ComplexPattern *, unsigned> &
+  getComplexPatternUsage() const {
+    return ComplexPatternUsage;
+  }
+
+  void increaseComplexPatternUsage(const ComplexPattern *CP) {
+    ComplexPatternUsage[CP]++;
+  }
+
   const CodeGenIntrinsic &getIntrinsic(Record *R) const {
     for (unsigned i = 0, e = Intrinsics.size(); i != e; ++i)
       if (Intrinsics[i].TheDef == R) return Intrinsics[i];
diff --git a/llvm/utils/TableGen/DAGISelMatcher.h b/llvm/utils/TableGen/DAGISelMatcher.h
index e3cf847edd1273b..9e962b14285c395 100644
--- a/llvm/utils/TableGen/DAGISelMatcher.h
+++ b/llvm/utils/TableGen/DAGISelMatcher.h
@@ -34,7 +34,7 @@ namespace llvm {
   class TreePattern;
 
 Matcher *ConvertPatternToMatcher(const PatternToMatch &Pattern,unsigned Variant,
-                                 const CodeGenDAGPatterns &CGP);
+                                 CodeGenDAGPatterns &CGP);
 void OptimizeMatcher(std::unique_ptr<Matcher> &Matcher,
                      const CodeGenDAGPatterns &CGP);
 void EmitMatcherTable(Matcher *Matcher, const CodeGenDAGPatterns &CGP,
diff --git a/llvm/utils/TableGen/DAGISelMatcherEmitter.cpp b/llvm/utils/TableGen/DAGISelMatcherEmitter.cpp
index 4a11991036efc11..aba1f04dfae9b64 100644
--- a/llvm/utils/TableGen/DAGISelMatcherEmitter.cpp
+++ b/llvm/utils/TableGen/DAGISelMatcherEmitter.cpp
@@ -63,7 +63,6 @@ class MatcherTableEmitter {
   StringMap<unsigned> PatternPredicateMap;
   std::vector<std::string> PatternPredicates;
 
-  DenseMap<const ComplexPattern*, unsigned> ComplexPatternMap;
   std::vector<const ComplexPattern*> ComplexPatterns;
 
 
@@ -85,7 +84,15 @@ class MatcherTableEmitter {
 
 public:
   MatcherTableEmitter(const CodeGenDAGPatterns &cgp)
-      : CGP(cgp), OpcodeCounts(Matcher::HighestKind + 1, 0) {}
+      : CGP(cgp), OpcodeCounts(Matcher::HighestKind + 1, 0) {
+    // Sort ComplexPatterns by usage.
+    auto &Usage = cgp.getComplexPatternUsage();
+    std::vector<std::pair<const ComplexPattern *, unsigned>> PatternList(
+        Usage.begin(), Usage.end());
+    sort(PatternList, [](auto &A, auto &B) { return A.second > B.second; });
+    for (auto &Pattern : PatternList)
+      ComplexPatterns.push_back(Pattern.first);
+  }
 
   unsigned EmitMatcherList(const Matcher *N, const unsigned Indent,
                            unsigned StartIdx, raw_ostream &OS);
@@ -146,12 +153,7 @@ class MatcherTableEmitter {
     return Entry-1;
   }
   unsigned getComplexPat(const ComplexPattern &P) {
-    unsigned &Entry = ComplexPatternMap[&P];
-    if (Entry == 0) {
-      ComplexPatterns.push_back(&P);
-      Entry = ComplexPatterns.size();
-    }
-    return Entry-1;
+    return llvm::find(ComplexPatterns, &P) - ComplexPatterns.begin();
   }
 
   unsigned getNodeXFormID(Record *Rec) {
@@ -625,8 +627,13 @@ EmitMatcher(const Matcher *N, const unsigned Indent, unsigned CurrentIdx,
   case Matcher::CheckComplexPat: {
     const CheckComplexPatMatcher *CCPM = cast<CheckComplexPatMatcher>(N);
     const ComplexPattern &Pattern = CCPM->getPattern();
-    OS << "OPC_CheckComplexPat, /*CP*/" << getComplexPat(Pattern) << ", /*#*/"
-       << CCPM->getMatchNumber() << ',';
+    unsigned PatternNo = getComplexPat(Pattern);
+    if (PatternNo < 8)
+      OS << "OPC_CheckComplexPat" << PatternNo << ", /*#*/"
+         << CCPM->getMatchNumber() << ',';
+    else
+      OS << "OPC_CheckComplexPat, /*CP*/" << PatternNo << ", /*#*/"
+         << CCPM->getMatchNumber() << ',';
 
     if (!OmitComments) {
       OS << " // " << Pattern.getSelectFunc();
@@ -638,7 +645,7 @@ EmitMatcher(const Matcher *N, const unsigned Indent, unsigned CurrentIdx,
         OS << " + chain result";
     }
     OS << '\n';
-    return 3;
+    return PatternNo < 8 ? 2 : 3;
   }
 
   case Matcher::CheckAndImm: {
diff --git a/llvm/utils/TableGen/DAGISelMatcherGen.cpp b/llvm/utils/TableGen/DAGISelMatcherGen.cpp
index d08f57b84b95f08..e6f6b7f47a882d7 100644
--- a/llvm/utils/TableGen/DAGISelMatcherGen.cpp
+++ b/llvm/utils/TableGen/DAGISelMatcherGen.cpp
@@ -56,7 +56,7 @@ static MVT::SimpleValueType getRegisterValueType(Record *R,
 namespace {
   class MatcherGen {
     const PatternToMatch &Pattern;
-    const CodeGenDAGPatterns &CGP;
+    CodeGenDAGPatterns &CGP;
 
     /// PatWithNoTypes - This is a clone of Pattern.getSrcPattern() that starts
     /// out with all of the types removed.  This allows us to insert type checks
@@ -102,7 +102,7 @@ namespace {
     /// which should have future checks stuck into its Next position.
     Matcher *CurPredicate;
   public:
-    MatcherGen(const PatternToMatch &pattern, const CodeGenDAGPatterns &cgp);
+    MatcherGen(const PatternToMatch &pattern, CodeGenDAGPatterns &cgp);
 
     bool EmitMatcherCode(unsigned Variant);
     void EmitResultCode();
@@ -146,7 +146,7 @@ namespace {
 } // end anonymous namespace
 
 MatcherGen::MatcherGen(const PatternToMatch &pattern,
-                       const CodeGenDAGPatterns &cgp)
+                       CodeGenDAGPatterns &cgp)
 : Pattern(pattern), CGP(cgp), NextRecordedOperandNo(0),
   TheMatcher(nullptr), CurPredicate(nullptr) {
   // We need to produce the matcher tree for the patterns source pattern.  To do
@@ -601,6 +601,7 @@ bool MatcherGen::EmitMatcherCode(unsigned Variant) {
 
     // Emit a CheckComplexPat operation, which does the match (aborting if it
     // fails) and pushes the matched operands onto the recorded nodes list.
+    CGP.increaseComplexPatternUsage(CP);
     AddMatcher(new CheckComplexPatMatcher(*CP, RecNodeEntry, N->getName(),
                                           NextRecordedOperandNo));
 
@@ -1081,7 +1082,7 @@ void MatcherGen::EmitResultCode() {
 /// the specified variant.  If the variant number is invalid, this returns null.
 Matcher *llvm::ConvertPatternToMatcher(const PatternToMatch &Pattern,
                                        unsigned Variant,
-                                       const CodeGenDAGPatterns &CGP) {
+                                       CodeGenDAGPatterns &CGP) {
   MatcherGen Gen(Pattern, CGP);
 
   // Generate the code for the matcher.

[github-actions]

✅ With the latest revision this PR passed the C/C++ code formatter.

[wangpc-pp]

Ping.

[wangpc-pp]

Ping.

[ilovepi]

This seems fine to me, and in line with the earlier patches. Would you mind adding some documentation about the change somewhere though? I feel like we should at least have a meta comment somewhere noting that the first 8 numbers are special.

You probably want to wait for one of the code owners to give the LGTM before landing, though.

[wangpc-pp]

This seems fine to me, and in line with the earlier patches. Would you mind adding some documentation about the change somewhere though? I feel like we should at least have a meta comment somewhere noting that the first 8 numbers are special.

Thanks! I'm working on adding some comments to the opcodes and will create a PR later.