Revert [Clang Interpreter] Initial patch for the constexpr interpreter

This reverts r370636 (git commit 8327fed9475a14c3376b4860c75370c730e08f33)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@370642 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Support/MathExtras.h

@@ -902,6 +902,9 @@ SubOverflow(T X, T Y, T &Result) {
 template <typename T>
 typename std::enable_if<std::is_signed<T>::value, T>::type
 MulOverflow(T X, T Y, T &Result) {
+#if __has_builtin(__builtin_mul_overflow)
+  return __builtin_mul_overflow(X, Y, &Result);
+#else
   // Perform the unsigned multiplication on absolute values.
   using U = typename std::make_unsigned<T>::type;
   const U UX = X < 0 ? (0 - static_cast<U>(X)) : static_cast<U>(X);
@@ -923,6 +926,7 @@ MulOverflow(T X, T Y, T &Result) {
     return UX > (static_cast<U>(std::numeric_limits<T>::max()) + U(1)) / UY;
   else
     return UX > (static_cast<U>(std::numeric_limits<T>::max())) / UY;
+#endif
 }
 
 } // End llvm namespace

utils/gn/secondary/clang/lib/AST/BUILD.gn

@@ -10,7 +10,6 @@ static_library("AST") {
     "//clang/include/clang/AST:CommentHTMLTags",
     "//clang/include/clang/AST:CommentHTMLTagsProperties",
     "//clang/include/clang/AST:DeclNodes",
-    "//clang/lib/AST/Interp",
     "//clang/lib/Basic",
     "//clang/lib/Lex",
     "//llvm/lib/BinaryFormat",

utils/gn/secondary/clang/lib/AST/Interp/BUILD.gn

@@ -1,39 +0,0 @@
-import("//clang/utils/TableGen/clang_tablegen.gni")
-
-clang_tablegen("Opcodes") {
-  args = [ "-gen-clang-opcodes" ]
-  td_file = "Opcodes.td"
-}
-
-static_library("Interp") {
-  output_name = "clangInterp"
-  configs += [ "//llvm/utils/gn/build:clang_code" ]
-  deps = [
-    "//clang/lib/AST/Interp:Opcodes",
-    "//clang/lib/Basic",
-    "//llvm/lib/Support",
-  ]
-  sources = [
-    "Block.cpp",
-    "ByteCodeEmitter.cpp",
-    "ByteCodeExprGen.cpp",
-    "ByteCodeGenError.cpp",
-    "ByteCodeStmtGen.cpp",
-    "Context.cpp",
-    "Descriptor.cpp",
-    "Disasm.cpp",
-    "EvalEmitter.cpp",
-    "Frame.cpp",
-    "Function.cpp",
-    "Interp.cpp",
-    "InterpFrame.cpp",
-    "InterpStack.cpp",
-    "InterpState.cpp",
-    "Pointer.cpp",
-    "Program.cpp",
-    "Record.cpp",
-    "Source.cpp",
-    "State.cpp",
-    "Type.cpp",
-  ]
-}

utils/gn/secondary/clang/utils/TableGen/BUILD.gn

@@ -14,7 +14,6 @@ executable("clang-tblgen") {
     "ClangOpenCLBuiltinEmitter.cpp",
     "ClangOptionDocEmitter.cpp",
     "ClangSACheckersEmitter.cpp",
-    "ClangOpcodesEmitter.cpp",
     "NeonEmitter.cpp",
     "TableGen.cpp",
   ]