[llvm] r268365 - [CodeGen] Add some space optimized forms of EmitNode and MorphNodeTo that implicitly indicate the number of result VTs. This shaves about 16K off the X86 matching table taking it down to about 470K.

[Craig Topper via llvm-commits]

Author: ctopper
Date: Tue May  3 00:54:13 2016
New Revision: 268365

URL: http://llvm.org/viewvc/llvm-project?rev=268365&view=rev
Log:
[CodeGen] Add some space optimized forms of EmitNode and MorphNodeTo that implicitly indicate the number of result VTs. This shaves about 16K off the X86 matching table taking it down to about 470K.

Overall this reduces the llc binary size with all in-tree targets by about 40K.

Modified:
    llvm/trunk/include/llvm/CodeGen/SelectionDAGISel.h
    llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
    llvm/trunk/utils/TableGen/DAGISelMatcherEmitter.cpp

Modified: llvm/trunk/include/llvm/CodeGen/SelectionDAGISel.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/SelectionDAGISel.h?rev=268365&r1=268364&r2=268365&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/SelectionDAGISel.h (original)
+++ llvm/trunk/include/llvm/CodeGen/SelectionDAGISel.h Tue May  3 00:54:13 2016
@@ -146,7 +146,11 @@ public:
     OPC_EmitCopyToReg,
     OPC_EmitNodeXForm,
     OPC_EmitNode,
+    // Space-optimized forms that implicitly encode number of result VTs.
+    OPC_EmitNode0, OPC_EmitNode1, OPC_EmitNode2,
     OPC_MorphNodeTo,
+    // Space-optimized forms that implicitly encode number of result VTs.
+    OPC_MorphNodeTo0, OPC_MorphNodeTo1, OPC_MorphNodeTo2,
     OPC_MarkGlueResults,
     OPC_CompleteMatch
   };

Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp?rev=268365&r1=268364&r2=268365&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp Tue May  3 00:54:13 2016
@@ -3305,13 +3305,22 @@ SelectCodeCommon(SDNode *NodeToMatch, co
       continue;
     }
 
-    case OPC_EmitNode:
-    case OPC_MorphNodeTo: {
+    case OPC_EmitNode:     case OPC_MorphNodeTo:
+    case OPC_EmitNode0:    case OPC_EmitNode1:    case OPC_EmitNode2:
+    case OPC_MorphNodeTo0: case OPC_MorphNodeTo1: case OPC_MorphNodeTo2: {
       uint16_t TargetOpc = MatcherTable[MatcherIndex++];
       TargetOpc |= (unsigned short)MatcherTable[MatcherIndex++] << 8;
       unsigned EmitNodeInfo = MatcherTable[MatcherIndex++];
       // Get the result VT list.
-      unsigned NumVTs = MatcherTable[MatcherIndex++];
+      unsigned NumVTs;
+      // If this is one of the compressed forms, get the number of VTs based
+      // on the Opcode. Otherwise read the next byte from the table.
+      if (Opcode >= OPC_MorphNodeTo0 && Opcode <= OPC_MorphNodeTo2)
+        NumVTs = Opcode - OPC_MorphNodeTo0;
+      else if (Opcode >= OPC_EmitNode0 && Opcode <= OPC_EmitNode2)
+        NumVTs = Opcode - OPC_EmitNode0;
+      else
+        NumVTs = MatcherTable[MatcherIndex++];
       SmallVector<EVT, 4> VTs;
       for (unsigned i = 0; i != NumVTs; ++i) {
         MVT::SimpleValueType VT =
@@ -3373,7 +3382,9 @@ SelectCodeCommon(SDNode *NodeToMatch, co
 
       // Create the node.
       SDNode *Res = nullptr;
-      if (Opcode != OPC_MorphNodeTo) {
+      bool IsMorphNodeTo = Opcode == OPC_MorphNodeTo ||
+                     (Opcode >= OPC_MorphNodeTo0 && Opcode <= OPC_MorphNodeTo2);
+      if (!IsMorphNodeTo) {
         // If this is a normal EmitNode command, just create the new node and
         // add the results to the RecordedNodes list.
         Res = CurDAG->getMachineNode(TargetOpc, SDLoc(NodeToMatch),
@@ -3453,11 +3464,11 @@ SelectCodeCommon(SDNode *NodeToMatch, co
       }
 
       DEBUG(dbgs() << "  "
-                   << (Opcode == OPC_MorphNodeTo ? "Morphed" : "Created")
+                   << (IsMorphNodeTo ? "Morphed" : "Created")
                    << " node: "; Res->dump(CurDAG); dbgs() << "\n");
 
       // If this was a MorphNodeTo then we're completely done!
-      if (Opcode == OPC_MorphNodeTo) {
+      if (IsMorphNodeTo) {
         // Update chain and glue uses.
         UpdateChainsAndGlue(NodeToMatch, InputChain, ChainNodesMatched,
                             InputGlue, GlueResultNodesMatched, true);

Modified: llvm/trunk/utils/TableGen/DAGISelMatcherEmitter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/utils/TableGen/DAGISelMatcherEmitter.cpp?rev=268365&r1=268364&r2=268365&view=diff
==============================================================================
--- llvm/trunk/utils/TableGen/DAGISelMatcherEmitter.cpp (original)
+++ llvm/trunk/utils/TableGen/DAGISelMatcherEmitter.cpp Tue May  3 00:54:13 2016
@@ -539,6 +539,10 @@ EmitMatcher(const Matcher *N, unsigned I
   case Matcher::MorphNodeTo: {
     const EmitNodeMatcherCommon *EN = cast<EmitNodeMatcherCommon>(N);
     OS << (isa<EmitNodeMatcher>(EN) ? "OPC_EmitNode" : "OPC_MorphNodeTo");
+    bool CompressVTs = EN->getNumVTs() < 3;
+    if (CompressVTs)
+      OS << EN->getNumVTs();
+
     OS << ", TARGET_VAL(" << EN->getOpcodeName() << "), 0";
 
     if (EN->hasChain())   OS << "|OPFL_Chain";
@@ -549,10 +553,13 @@ EmitMatcher(const Matcher *N, unsigned I
       OS << "|OPFL_Variadic" << EN->getNumFixedArityOperands();
     OS << ",\n";
 
-    OS.PadToColumn(Indent*2+4) << EN->getNumVTs();
-    if (!OmitComments)
-      OS << "/*#VTs*/";
-    OS << ", ";
+    OS.PadToColumn(Indent*2+4);
+    if (!CompressVTs) {
+      OS << EN->getNumVTs();
+      if (!OmitComments)
+        OS << "/*#VTs*/";
+      OS << ", ";
+    }
     for (unsigned i = 0, e = EN->getNumVTs(); i != e; ++i)
       OS << getEnumName(EN->getVT(i)) << ", ";
 
@@ -586,7 +593,7 @@ EmitMatcher(const Matcher *N, unsigned I
     } else
       OS << '\n';
 
-    return 6+EN->getNumVTs()+NumOperandBytes;
+    return 5 + !CompressVTs + EN->getNumVTs() + NumOperandBytes;
   }
   case Matcher::MarkGlueResults: {
     const MarkGlueResultsMatcher *CFR = cast<MarkGlueResultsMatcher>(N);