[llvm] a3a7e76 - [SelectionDAG] Add Opc_CheckPatternPredicate2 to support targets with more than 256 predicates.

[Craig Topper via llvm-commits]

Author: Craig Topper
Date: 2023-08-05T16:59:45-07:00
New Revision: a3a7e76893b81934b9aaa4ecfe8f24496c48ddab

URL: https://github.com/llvm/llvm-project/commit/a3a7e76893b81934b9aaa4ecfe8f24496c48ddab
DIFF: https://github.com/llvm/llvm-project/commit/a3a7e76893b81934b9aaa4ecfe8f24496c48ddab.diff

LOG: [SelectionDAG] Add Opc_CheckPatternPredicate2 to support targets with more than 256 predicates.

This is an alternative to D156967 where I suggested the author
could use a VBR type.

This patch takes inspirations from Opc_EmitRegister2 that is used
for two byte registers.

I'm assuming 1 or 2 byte predicates should be enough so we don't
need the fully generality of VBR.

This avoids impacting the table size on targets that have more than
128 predicates already like X86.

Reviewed By: bogner

Differential Revision: https://reviews.llvm.org/D157196

Added: 
    

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

Removed: 
    


################################################################################
diff  --git a/llvm/include/llvm/CodeGen/SelectionDAGISel.h b/llvm/include/llvm/CodeGen/SelectionDAGISel.h
index 6c0b2cfe8ef31d..bda532e5761494 100644
--- a/llvm/include/llvm/CodeGen/SelectionDAGISel.h
+++ b/llvm/include/llvm/CodeGen/SelectionDAGISel.h
@@ -128,6 +128,7 @@ class SelectionDAGISel : public MachineFunctionPass {
     OPC_CheckChild0Same, OPC_CheckChild1Same,
     OPC_CheckChild2Same, OPC_CheckChild3Same,
     OPC_CheckPatternPredicate,
+    OPC_CheckPatternPredicate2,
     OPC_CheckPredicate,
     OPC_CheckPredicateWithOperands,
     OPC_CheckOpcode,

diff  --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index 35abd990f96899..5544d7d84d8c68 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -2639,8 +2639,11 @@ LLVM_ATTRIBUTE_ALWAYS_INLINE static bool CheckChildSame(
 /// CheckPatternPredicate - Implements OP_CheckPatternPredicate.
 LLVM_ATTRIBUTE_ALWAYS_INLINE static bool
 CheckPatternPredicate(const unsigned char *MatcherTable, unsigned &MatcherIndex,
-                      const SelectionDAGISel &SDISel) {
-  return SDISel.CheckPatternPredicate(MatcherTable[MatcherIndex++]);
+                      const SelectionDAGISel &SDISel, bool TwoBytePredNo) {
+  unsigned PredNo = MatcherTable[MatcherIndex++];
+  if (TwoBytePredNo)
+    PredNo |= MatcherTable[MatcherIndex++] << 8;
+  return SDISel.CheckPatternPredicate(PredNo);
 }
 
 /// CheckNodePredicate - Implements OP_CheckNodePredicate.
@@ -2788,7 +2791,10 @@ static unsigned IsPredicateKnownToFail(const unsigned char *Table,
                         Table[Index-1] - SelectionDAGISel::OPC_CheckChild0Same);
     return Index;
   case SelectionDAGISel::OPC_CheckPatternPredicate:
-    Result = !::CheckPatternPredicate(Table, Index, SDISel);
+  case SelectionDAGISel::OPC_CheckPatternPredicate2:
+    Result = !::CheckPatternPredicate(
+        Table, Index, SDISel,
+        Table[Index - 1] == SelectionDAGISel::OPC_CheckPatternPredicate2);
     return Index;
   case SelectionDAGISel::OPC_CheckPredicate:
     Result = !::CheckNodePredicate(Table, Index, SDISel, N.getNode());
@@ -3198,7 +3204,10 @@ void SelectionDAGISel::SelectCodeCommon(SDNode *NodeToMatch,
       continue;
 
     case OPC_CheckPatternPredicate:
-      if (!::CheckPatternPredicate(MatcherTable, MatcherIndex, *this)) break;
+    case OPC_CheckPatternPredicate2:
+      if (!::CheckPatternPredicate(MatcherTable, MatcherIndex, *this,
+                                   Opcode == OPC_CheckPatternPredicate2))
+        break;
       continue;
     case OPC_CheckPredicate:
       if (!::CheckNodePredicate(MatcherTable, MatcherIndex, *this,

diff  --git a/llvm/utils/TableGen/DAGISelMatcherEmitter.cpp b/llvm/utils/TableGen/DAGISelMatcherEmitter.cpp
index 28d4d585f3ddd0..4a11991036efc1 100644
--- a/llvm/utils/TableGen/DAGISelMatcherEmitter.cpp
+++ b/llvm/utils/TableGen/DAGISelMatcherEmitter.cpp
@@ -472,12 +472,16 @@ EmitMatcher(const Matcher *N, const unsigned Indent, unsigned CurrentIdx,
     return 2;
 
   case Matcher::CheckPatternPredicate: {
-    StringRef Pred =cast<CheckPatternPredicateMatcher>(N)->getPredicate();
-    OS << "OPC_CheckPatternPredicate, " << getPatternPredicate(Pred) << ',';
+    StringRef Pred = cast<CheckPatternPredicateMatcher>(N)->getPredicate();
+    unsigned PredNo = getPatternPredicate(Pred);
+    if (PredNo > 255)
+      OS << "OPC_CheckPatternPredicate2, TARGET_VAL(" << PredNo << "),";
+    else
+      OS << "OPC_CheckPatternPredicate, " << PredNo << ',';
     if (!OmitComments)
       OS << " // " << Pred;
     OS << '\n';
-    return 2;
+    return 2 + (PredNo > 255);
   }
   case Matcher::CheckPredicate: {
     TreePredicateFn Pred = cast<CheckPredicateMatcher>(N)->getPredicate();