[c++20] P0515R3: Parsing support and basic AST construction for operator <=>.

Adding the new enumerator forced a bunch more changes into this patch than I
would have liked. The -Wtautological-compare warning was extended to properly
check the new comparison operator, clang-format needed updating because it uses
precedence levels as weights for determining where to break lines (and several
operators increased their precedence levels with this change), thread-safety
analysis needed changes to build its own IL properly for the new operator.

All "real" semantic checking for this operator has been deferred to a future
patch. For now, we use the relational comparison rules and arbitrarily give
the builtin form of the operator a return type of 'void'.

llvm-svn: 320707

1 files changed, 8 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 8c6d11b4957..929806ac6bf 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -11375,6 +11375,7 @@ BinaryOperatorKind Sema::ConvertTokenKindToBinaryOpcode(tok::TokenKind Kind) {
   case tok::greater:              Opc = BO_GT; break;
   case tok::exclaimequal:         Opc = BO_NE; break;
   case tok::equalequal:           Opc = BO_EQ; break;
+  case tok::spaceship:            Opc = BO_Cmp; break;
   case tok::amp:                  Opc = BO_And; break;
   case tok::caret:                Opc = BO_Xor; break;
   case tok::pipe:                 Opc = BO_Or; break;
@@ -11683,6 +11684,13 @@ ExprResult Sema::CreateBuiltinBinOp(SourceLocation OpLoc,
     ConvertHalfVec = true;
     ResultTy = CheckCompareOperands(LHS, RHS, OpLoc, Opc, false);
     break;
+  case BO_Cmp:
+    // FIXME: Implement proper semantic checking of '<=>'.
+    ConvertHalfVec = true;
+    ResultTy = CheckCompareOperands(LHS, RHS, OpLoc, Opc, true);
+    if (!ResultTy.isNull())
+      ResultTy = Context.VoidTy;
+    break;
   case BO_And:
     checkObjCPointerIntrospection(*this, LHS, RHS, OpLoc);
     LLVM_FALLTHROUGH;