AMDGPU: Avoid emitting "true" predicates

Empty condition strings are considerde always true. This removes a lot
of clutter from the generated matcher tables.

This shrinks the source size of AMDGPUGenDAGISel.inc from 7.3M to
6.1M.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@367326 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/AMDGPU/AMDGPUInstructions.td b/lib/Target/AMDGPU/AMDGPUInstructions.td
index 6efd578807e1a4ef2e0b6edc8473457e89bc472b..885bfc7824c07c4e175b89b82d28b0359d300d87 100644 (file)
--- a/lib/Target/AMDGPU/AMDGPUInstructions.td
+++ b/lib/Target/AMDGPU/AMDGPUInstructions.td
@@ -75,7 +75,7 @@ class ILFormat<dag outs, dag ins, string asmstr, list<dag> pattern>
      let isCodeGenOnly = 1;
 }
 
-def TruePredicate : Predicate<"true">;
+def TruePredicate : Predicate<"">;
 
 class PredicateControl {
   Predicate SubtargetPredicate = TruePredicate;

diff --git a/utils/TableGen/CodeGenDAGPatterns.cpp b/utils/TableGen/CodeGenDAGPatterns.cpp
index c8f710d66a03663f64e2bc9076d5a44705f72dc6..75890d2718dda0e528dba68fe3c51a7bb0905d70 100644 (file)
--- a/utils/TableGen/CodeGenDAGPatterns.cpp
+++ b/utils/TableGen/CodeGenDAGPatterns.cpp
@@ -1373,8 +1373,10 @@ getPatternComplexity(const CodeGenDAGPatterns &CGP) const {
 ///
 std::string PatternToMatch::getPredicateCheck() const {
   SmallVector<const Predicate*,4> PredList;
-  for (const Predicate &P : Predicates)
-    PredList.push_back(&P);
+  for (const Predicate &P : Predicates) {
+    if (!P.getCondString().empty())
+      PredList.push_back(&P);
+  }
   llvm::sort(PredList, deref<llvm::less>());
 
   std::string Check;

diff --git a/utils/TableGen/CodeGenDAGPatterns.h b/utils/TableGen/CodeGenDAGPatterns.h
index 2b49a64c3f1d685f959094989fcbe0144a6e1d04..d41de68f02ffabd82d1bfd76624bcc2f94d4c405 100644 (file)
--- a/utils/TableGen/CodeGenDAGPatterns.h
+++ b/utils/TableGen/CodeGenDAGPatterns.h
@@ -1075,8 +1075,11 @@ public:
     std::string C = IsHwMode
         ? std::string("MF->getSubtarget().checkFeatures(\"" + Features + "\")")
         : std::string(Def->getValueAsString("CondString"));
+    if (C.empty())
+      return "";
     return IfCond ? C : "!("+C+')';
   }
+
   bool operator==(const Predicate &P) const {
     return IfCond == P.IfCond && IsHwMode == P.IsHwMode && Def == P.Def;
   }

diff --git a/utils/TableGen/GlobalISelEmitter.cpp b/utils/TableGen/GlobalISelEmitter.cpp
index f1c02134198bd3e431e288b4698d72de7260cbbc..65c96069808546d805ef5668681bbb8ab031815e 100644 (file)
--- a/utils/TableGen/GlobalISelEmitter.cpp
+++ b/utils/TableGen/GlobalISelEmitter.cpp
@@ -3212,7 +3212,7 @@ Error
 GlobalISelEmitter::importRulePredicates(RuleMatcher &M,
                                         ArrayRef<Predicate> Predicates) {
   for (const Predicate &P : Predicates) {
-    if (!P.Def)
+    if (!P.Def || P.getCondString().empty())
       continue;
     declareSubtargetFeature(P.Def);
     M.addRequiredFeature(P.Def);

diff --git a/utils/TableGen/SubtargetFeatureInfo.cpp b/utils/TableGen/SubtargetFeatureInfo.cpp
index edf0b4a01c6dc7bc68e9042577c1d60d5e295277..33475f2d111bef87e228f0fb824012c8c7bb0d36 100644 (file)
--- a/utils/TableGen/SubtargetFeatureInfo.cpp
+++ b/utils/TableGen/SubtargetFeatureInfo.cpp
@@ -38,6 +38,10 @@ SubtargetFeatureInfo::getAll(const RecordKeeper &Records) {
     if (Pred->getName().empty())
       PrintFatalError(Pred->getLoc(), "Predicate has no name!");
 
+    // Ignore always true predicates.
+    if (Pred->getValueAsString("CondString").empty())
+      continue;
+
     SubtargetFeatures.emplace_back(
         Pred, SubtargetFeatureInfo(Pred, SubtargetFeatures.size()));
   }
@@ -95,8 +99,10 @@ void SubtargetFeatureInfo::emitComputeAvailableFeatures(
   OS << "  PredicateBitset Features;\n";
   for (const auto &SF : SubtargetFeatures) {
     const SubtargetFeatureInfo &SFI = SF.second;
+    StringRef CondStr = SFI.TheDef->getValueAsString("CondString");
+    assert(!CondStr.empty() && "true predicate should have been filtered");
 
-    OS << "  if (" << SFI.TheDef->getValueAsString("CondString") << ")\n";
+    OS << "  if (" << CondStr << ")\n";
     OS << "    Features[" << SFI.getEnumBitName() << "] = 1;\n";
   }
   OS << "  return Features;\n";