[flang] Fix preprocessor tokenization of .NE. style operators.

Original-commit: flang-compiler/f18@ab547b89e8
Reviewed-on: https://github.com/flang-compiler/f18/pull/81
Tree-same-pre-rewrite: false

flang/lib/parser/grammar.h

@@ -2755,9 +2755,10 @@ TYPE_PARSER(construct<format::FormatItem>(
 // R1302 format-specification ->
 //         ( [format-items] ) | ( [format-items ,] unlimited-format-item )
 // R1305 unlimited-format-item -> * ( format-items )
-TYPE_PARSER(parenthesized(
-    construct<format::FormatSpecification>(
-        defaulted(formatItems / ","), "*" >> parenthesized(formatItems)) ||
+// minor extension: the comma is optional before the unlimited-format-item
+TYPE_PARSER(parenthesized(construct<format::FormatSpecification>(
+                              defaulted(formatItems / maybe(","_tok)),
+                              "*" >> parenthesized(formatItems)) ||
     construct<format::FormatSpecification>(defaulted(formatItems))))
 // R1308 w -> digit-string
 // R1309 m -> digit-string

flang/lib/parser/preprocessor.cc

@@ -720,7 +720,7 @@ static std::int64_t ExpressionValue(const TokenSequence &token,
       14, 14,  // unary +, -
       13, 12, 12, 12, 11, 11, 10, 10,  // **, *, /, %, +, -, <<, >>
       9, 8, 7,  // &, ^, |
-      6, 6, 6, 6, 6, 6,  // relations
+      6, 6, 6, 6, 6, 6,  // relations .LT. to .GT.
       5, 4, 3, 2, 2,  // .NOT., .AND., .OR., .EQV., .NEQV.
       1, 0  // ?: and ,
   };

flang/lib/parser/prescan.cc

@@ -344,7 +344,7 @@ bool Prescanner::NextToken(TokenSequence *tokens) {
     preventHollerith_ = false;
   } else if (*at_ == '.') {
     char nch{EmitCharAndAdvance(tokens, '.')};
-    if (IsDecimalDigit(nch)) {
+    if (!inPreprocessorDirective_ && IsDecimalDigit(nch)) {
       while (IsDecimalDigit(EmitCharAndAdvance(tokens, *at_))) {
       }
       ExponentAndKind(tokens);