Promote isSameTemplateArg, and use llvm::APSInt::isSameValue

Author: zwuis

clang/lib/AST/ASTContext.cpp

@@ -7648,7 +7648,7 @@ bool ASTContext::isSameTemplateArgument(const TemplateArgument &Arg1,
 
   switch (Arg1.getKind()) {
   case TemplateArgument::Null:
-    return true;
+    llvm_unreachable("Comparing NULL template argument");
 
   case TemplateArgument::Type:
     return hasSameType(Arg1.getAsType(), Arg2.getAsType());
@@ -7666,7 +7666,8 @@ bool ASTContext::isSameTemplateArgument(const TemplateArgument &Arg1,
            getCanonicalTemplateName(Arg2.getAsTemplateOrTemplatePattern());
 
   case TemplateArgument::Integral:
-    return Arg1.getAsIntegral() == Arg2.getAsIntegral();
+    return llvm::APSInt::isSameValue(Arg1.getAsIntegral(),
+                                     Arg2.getAsIntegral());
 
   case TemplateArgument::StructuralValue:
     return Arg1.structurallyEquals(Arg2);

clang/lib/Sema/SemaTemplateDeduction.cpp

@@ -114,27 +114,6 @@ namespace clang {
 using namespace clang;
 using namespace sema;
 
-/// Compare two APSInts, extending and switching the sign as
-/// necessary to compare their values regardless of underlying type.
-static bool hasSameExtendedValue(llvm::APSInt X, llvm::APSInt Y) {
-  if (Y.getBitWidth() > X.getBitWidth())
-    X = X.extend(Y.getBitWidth());
-  else if (Y.getBitWidth() < X.getBitWidth())
-    Y = Y.extend(X.getBitWidth());
-
-  // If there is a signedness mismatch, correct it.
-  if (X.isSigned() != Y.isSigned()) {
-    // If the signed value is negative, then the values cannot be the same.
-    if ((Y.isSigned() && Y.isNegative()) || (X.isSigned() && X.isNegative()))
-      return false;
-
-    Y.setIsSigned(true);
-    X.setIsSigned(true);
-  }
-
-  return X == Y;
-}
-
 /// The kind of PartialOrdering we're performing template argument deduction
 /// for (C++11 [temp.deduct.partial]).
 enum class PartialOrderingKind { None, NonCall, Call };
@@ -273,7 +252,7 @@ checkDeducedTemplateArguments(ASTContext &Context,
     if (Y.getKind() == TemplateArgument::Expression ||
         Y.getKind() == TemplateArgument::Declaration ||
         (Y.getKind() == TemplateArgument::Integral &&
-         hasSameExtendedValue(X.getAsIntegral(), Y.getAsIntegral())))
+         llvm::APSInt::isSameValue(X.getAsIntegral(), Y.getAsIntegral())))
       return X.wasDeducedFromArrayBound() ? Y : X;
 
     // All other combinations are incompatible.
@@ -2574,7 +2553,7 @@ DeduceTemplateArguments(Sema &S, TemplateParameterList *TemplateParams,
 
   case TemplateArgument::Integral:
     if (A.getKind() == TemplateArgument::Integral) {
-      if (hasSameExtendedValue(P.getAsIntegral(), A.getAsIntegral()))
+      if (llvm::APSInt::isSameValue(P.getAsIntegral(), A.getAsIntegral()))
         return TemplateDeductionResult::Success;
     }
     Info.FirstArg = P;
@@ -2828,44 +2807,6 @@ TemplateDeductionResult Sema::DeduceTemplateArguments(
       /*HasDeducedAnyParam=*/nullptr);
 }
 
-/// Determine whether two template arguments are the same.
-static bool isSameTemplateArg(ASTContext &Context, const TemplateArgument &X,
-                              const TemplateArgument &Y) {
-  if (X.getKind() != Y.getKind())
-    return false;
-
-  switch (X.getKind()) {
-    case TemplateArgument::Null:
-      llvm_unreachable("Comparing NULL template argument");
-
-    case TemplateArgument::Type:
-    case TemplateArgument::Declaration:
-    case TemplateArgument::NullPtr:
-    case TemplateArgument::Template:
-    case TemplateArgument::TemplateExpansion:
-    case TemplateArgument::StructuralValue:
-    case TemplateArgument::Expression:
-      return Context.isSameTemplateArgument(X, Y);
-
-    case TemplateArgument::Integral:
-      return hasSameExtendedValue(X.getAsIntegral(), Y.getAsIntegral());
-
-    case TemplateArgument::Pack: {
-      unsigned PackIterationSize = X.pack_size();
-      if (X.pack_size() != Y.pack_size())
-        return false;
-      ArrayRef<TemplateArgument> XP = X.pack_elements();
-      ArrayRef<TemplateArgument> YP = Y.pack_elements();
-      for (unsigned i = 0; i < PackIterationSize; ++i)
-        if (!isSameTemplateArg(Context, XP[i], YP[i]))
-          return false;
-      return true;
-    }
-  }
-
-  llvm_unreachable("Invalid TemplateArgument Kind!");
-}
-
 TemplateArgumentLoc
 Sema::getTrivialTemplateArgumentLoc(const TemplateArgument &Arg,
                                     QualType NTTPType, SourceLocation Loc,
@@ -3331,7 +3272,7 @@ static TemplateDeductionResult FinishTemplateArgumentDeduction(
       break;
     TemplateArgument PP = P.isPackExpansion() ? P.getPackExpansionPattern() : P,
                      PA = A.isPackExpansion() ? A.getPackExpansionPattern() : A;
-    if (!isSameTemplateArg(S.Context, PP, PA)) {
+    if (!S.Context.isSameTemplateArgument(PP, PA)) {
       if (!P.isPackExpansion() && !A.isPackExpansion()) {
         Info.Param = makeTemplateParameter(TPL->getParam(
             (AsStack.empty() ? As.end() : AsStack.back().begin()) -