Hi!
On Wed, Mar 11, 2020 at 12:00:12PM -0700, Carl Love wrote:
> The following patch add a check to make sure the user did not specify
> -mno_fprnd with the builtins __builtin_vsx_xsrdpim and
> __builtin_vsx_xsrdpip. These builtins are incompatible with the
> -mno_fprnd command line. The check prevents GCC crashing under these
> conditions.
(-mno-fprnd, a dash, not an underscore)
-mfprnd means all new insns in ISA 2.04; we should never allow this
option together with a -mcpu= that implies 2.04 or higher.
xsrdpi* require ISA 2.06 (Power7), so this testcase should work *anyway*,
even if fri* would be disabled for some strange reason.
> I read thru the source code looking for other builtins with the same
> issue.
>From the GCC manual:
-mmfcrf p4 2.01
-mpopcntb p5 2.02
-mfprnd p5+ 2.04 ("info gcc" says 2.03, that's wrong? But the ISA
says this is 2.02 even? Now what!)
-mcmpb p6 2.05
-mpopcntd p7 2.06
(and there are more, in fact).
> 2020-03-10 Carl Love <c...@us.ibm.com>
>
> * gcc/config/rs6000/rs6000-c.c
> (altivec_resolve_overloaded_builtin):
> Add check for TARGET_FRND and VSX_BUILTIN_XSRDPIM,
> VSX_BUILTIN_XSRDPIP
> compatibility.
FPRND
> --- a/gcc/config/rs6000/rs6000-c.c
> +++ b/gcc/config/rs6000/rs6000-c.c
> @@ -915,6 +915,14 @@ altivec_resolve_overloaded_builtin (location_t
> loc, tree fndecl,
> const struct altivec_builtin_types *desc;
> unsigned int n;
>
> + /* Check builtin for command line argument conflicts. */
> + if (!TARGET_FPRND &&
> + (fcode == VSX_BUILTIN_XSRDPIM || fcode == VSX_BUILTIN_XSRDPIP))
Lines never end in binary operators: that goes to the start of the next
line, instead, so
if (!TARGET_FPRND
&& (fcode == VSX_BUILTIN_XSRDPIM || fcode == VSX_BUILTIN_XSRDPIP))
I'd write that the other way around, it reads nicer:
if ((fcode == VSX_BUILTIN_XSRDPIM || fcode == VSX_BUILTIN_XSRDPIP)
&& !TARGET_FPRND)
but maybe that is just taste :-)
> {
> + error ("%s is incompatible with mno-fprnd option",
> + IDENTIFIER_POINTER (DECL_NAME (fndecl)));
> + return error_mark_node;
> + }
-mno-fprnd (options start with a dash, except in the first field in
rs6000.opt).
It would be better if you disallowed this option combination? Don't
allow an options that says ISA X insns are allowed, but ISA Y insns are
not, with Y < X. In this case X is 2.06 and Y is 2.02 or 2.03 or 2.04.
Segher
