re PR fortran/47359 (Recursive functions of intrinsic names generates invalid assembler)

2015-06-06  Thomas Koenig  <tkoenig@netcologne.de>

	PR fortran/47359
	* arith.c (eval_intrinsic_op): Set warn flag for
	gfc_type_convert_binary if -Wconversion or -Wconversion-extra
	are set.
	(wprecision_real_real): New function.
	(wprecision_int_real): New function.
	(gfc_int2int): If -fno-range-check and -Wconversion are specified
	and it is a narrowing conversion, warn.
	(gfc_int2real): If there is a change in value for the conversion,
	warn.
	(gfc_int2complex):  Likewise.
	(gfc_real2int): If there is a fractional part to the real number,
	warn with -Wconversion, otherwise warn with -Wconversion-extra.
	(gfc_real2real): Emit warning if the constant was changed by
	conversion with either -Wconversion or -Wconversion-extra.  With
	-Wconversion-extra, warn if no warning was issued earlier.
	(gfc_real2complex):  Likewise.
	(gfc_complex2int): For -Wconversion or -Wconversion-extra, if
	there was an imaginary part, warn; otherwise, warn for change in
	value.  Warn with -Wconversion-extra if no other warning was
	issued.
	(gfc_complex2real): For -Wconversion or -Wconversion-extra, if
	there was an imaginary part, warn; otherwise, warn for change in
	value. Warn with -Wconversion-extra if no other warning was
	issued.
	(gfc_complex2complex):  For -Wconversion, warn if the value of
	either the real or the imaginary part was changed.  Warn for
	-Wconversion-extra if no prior warning was issued.
	* expr.c (gfc_check_assign):  Remove check for change in value.
	* primary.c (match_real_constant): For -Wconversion-extra, check
	against a number in which the last non-zero digit has been
	replaced with a zero.  If the number compares equal, warn.
	* intrinsic.c (gfc_convert_type_warn):  Do not warn about constant
	conversions.

2015-06-06  Thomas Koenig  <tkoenig@netcologne.de>

	PR fortran/47359
	* gfortran.dg/array_constructor_type_17.f03: Adjust error message.
	* gfortran.dg/warn_conversion.f90: Add warning for change in value
	for assignment.
	* gfortran.dg/warn_conversion_3.f90: Add warnings.
	* gfortran.dg/warn_conversion_5.f90: New test.
	* gfortran.dg/warn_conversion_6.f90: New test.
	* gfortran.dg/warn_conversion_7.f90: New test.

From-SVN: r224190

1 files changed, 52 insertions, 0 deletions

diff --git a/gcc/fortran/primary.c b/gcc/fortran/primary.c
index 7d2f9c7..e467e0b 100644
--- a/gcc/fortran/primary.c
+++ b/gcc/fortran/primary.c
@@ -736,6 +736,58 @@ done:
       gfc_internal_error ("gfc_range_check() returned bad value");
     }
 
+  /* Warn about trailing digits which suggest the user added too many
+     trailing digits, which may cause the appearance of higher pecision
+     than the kind kan support.
+
+     This is done by replacing the rightmost non-zero digit with zero
+     and comparing with the original value.  If these are equal, we
+     assume the user supplied more digits than intended (or forgot to
+     convert to the correct kind).
+  */
+
+  if (warn_conversion_extra)
+    {
+      mpfr_t r;
+      char *c, *p;
+      bool did_break;
+
+      c = strchr (buffer, 'e');
+      if (c == NULL)
+	c = buffer + strlen(buffer);
+
+      did_break = false;
+      for (p = c - 1; p >= buffer; p--)
+	{
+	  if (*p == '.')
+	    continue;
+	  
+	  if (*p != '0')
+	    {
+	      *p = '0';
+	      did_break = true;
+	      break;
+	    }
+	}
+
+      if (did_break)
+	{
+	  mpfr_init (r);
+	  mpfr_set_str (r, buffer, 10, GFC_RND_MODE);
+	  if (negate)
+	    mpfr_neg (r, r, GFC_RND_MODE);
+
+	  mpfr_sub (r, r, e->value.real, GFC_RND_MODE);
+
+	  if (mpfr_cmp_ui (r, 0) == 0)
+	    gfc_warning (OPT_Wconversion_extra, "Non-significant digits "
+			 "in %qs number at %C, maybe incorrect KIND",
+			 gfc_typename (&e->ts));
+
+	  mpfr_clear (r);
+	}
+    }
+
   *result = e;
   return MATCH_YES;