variations on hex float constants

Author: Daniel Kroening

regression/ansi-c/float_constant1/main.c

@@ -7,6 +7,9 @@ STATIC_ASSERT(0x1.0p-95f == 2.524355e-29f);
 // also with upper case X, P, F
 STATIC_ASSERT(0X1.0P-95F == 2.524355e-29f);
 
+// nothing before the dot
+STATIC_ASSERT(0X.0p+1f == 0);
+
 #ifdef __GNUC__
 _Complex c;
 #endif

src/ansi-c/scanner.l

@@ -167,9 +167,9 @@ fraction        {integer}
 float1          {integer}"."{fraction}?({exponent})?
 float2          "."{fraction}({exponent})?
 float3          {integer}{exponent}
-hexfloat1       "0"[xX]{hexdigit}+"."{hexdigit}+[pP][+-]?{integer}
-hexfloat2       "0"[xX]{hexdigit}+"."[pP][+-]?{integer}
-hexfloat3       "0"[xX]{hexdigit}+[pP][+-]?{integer}
+hexfloat1       "0"[xX]{hexdigit}*"."{hexdigit}+[pP][+-]?{integer}
+hexfloat2       "0"[xX]{hexdigit}*"."[pP][+-]?{integer}
+hexfloat3       "0"[xX]{hexdigit}*[pP][+-]?{integer}
 float_suffix    [fFlLiIjJ]*
 gcc_ext_float_suffix    [wWqQ]|[dD][fFdDlL]?
 float           {float1}|{float2}|{float3}|{hexfloat1}|{hexfloat2}|{hexfloat3}