Fix a bug handling hex floats in c90 mode, pointed out by Neil.

llvm-svn: 44120

clang/Lex/LiteralSupport.cpp

@@ -224,7 +224,7 @@ NumericLiteralParser(const char *begin, const char *end,
       }
       // A binary exponent can appear with or with a '.'. If dotted, the
       // binary exponent is required. 
-      if (*s == 'p' || *s == 'P') { 
+      if ((*s == 'p' || *s == 'P') && PP.getLangOptions().HexFloats) { 
         s++;
         saw_exponent = true;
         if (*s == '+' || *s == '-')  s++; // sign

clang/test/Lexer/c90.c

@@ -0,0 +1,5 @@
+// RUN: clang -std=c90 -fsyntax-only %s -verify
+
+enum { cast_hex = (long) (
+      0x0p-1   /* expected-error {{invalid suffix 'p' on integer constant}} */
+     ) };