From 9ec06a15d644bf63b0cbb004c0f0b8d2880cee76 Mon Sep 17 00:00:00 2001 From: Jim Grosbach Date: Mon, 18 Jun 2012 19:45:46 +0000 Subject: TableGen: AsmMatcher missing-features list minimization. When returning a 'cannot match due to missing CPU features' error code, if there are multiple potential matches with different feature sets, return the smallest set of missing features from the alternatives as that's most likely to be the one that's desired. llvm-svn: 158673 --- llvm/utils/TableGen/AsmMatcherEmitter.cpp | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/llvm/utils/TableGen/AsmMatcherEmitter.cpp b/llvm/utils/TableGen/AsmMatcherEmitter.cpp index e980b1a7d9d..f88e3371416 100644 --- a/llvm/utils/TableGen/AsmMatcherEmitter.cpp +++ b/llvm/utils/TableGen/AsmMatcherEmitter.cpp @@ -2575,6 +2575,7 @@ void AsmMatcherEmitter::run(raw_ostream &OS) { OS << " bool HadMatchOtherThanFeatures = false;\n"; OS << " bool HadMatchOtherThanPredicate = false;\n"; OS << " unsigned RetCode = Match_InvalidOperand;\n"; + OS << " unsigned MissingFeatures = ~0U;\n"; OS << " // Set ErrorInfo to the operand that mismatches if it is\n"; OS << " // wrong for all instances of the instruction.\n"; OS << " ErrorInfo = ~0U;\n"; @@ -2622,7 +2623,11 @@ void AsmMatcherEmitter::run(raw_ostream &OS) { OS << " if ((AvailableFeatures & it->RequiredFeatures) " << "!= it->RequiredFeatures) {\n"; OS << " HadMatchOtherThanFeatures = true;\n"; - OS << " ErrorInfo = it->RequiredFeatures & ~AvailableFeatures;\n"; + OS << " unsigned NewMissingFeatures = it->RequiredFeatures & " + "~AvailableFeatures;\n"; + OS << " if (CountPopulation_32(NewMissingFeatures) <= " + "CountPopulation_32(MissingFeatures))\n"; + OS << " MissingFeatures = NewMissingFeatures;\n"; OS << " continue;\n"; OS << " }\n"; OS << "\n"; @@ -2656,8 +2661,9 @@ void AsmMatcherEmitter::run(raw_ostream &OS) { OS << " // Okay, we had no match. Try to return a useful error code.\n"; OS << " if (HadMatchOtherThanPredicate || !HadMatchOtherThanFeatures)"; - OS << " return RetCode;\n"; - OS << " assert(ErrorInfo && \"missing feature(s) but what?!\");"; + OS << " return RetCode;\n"; + OS << " // Missing feature matches return which features were missing\n"; + OS << " ErrorInfo = MissingFeatures;\n"; OS << " return Match_MissingFeature;\n"; OS << "}\n\n"; -- cgit v1.2.3