On Wed, 7 Apr 2021, Patrick McGehearty via Gcc-patches wrote:
> + macro_name = XALLOCAVEC (char, name_len
> + + sizeof ("__LIBGCC__EXCESS_PRECISION__"));
> sprintf (macro_name, "__LIBGCC_%s_EXCESS_PRECISION__", name);
> builtin_define_with_int_value (macro_name, excess_precision);
> +
> + char val_name[64];
> +
> + macro_name = XALLOCAVEC (char, name_len
> + + sizeof ("__LIBGCC_EPSILON__"));
> + sprintf (macro_name, "__LIBGCC_%s_EPSILON__", name);
> + sprintf (val_name, "__%s_EPSILON__", float_h_prefix);
> + builtin_define_with_value (macro_name, val_name, 0);
> +
> + macro_name = XALLOCAVEC (char, name_len + sizeof ("__LIBGCC_MAX__"));
> + sprintf (macro_name, "__LIBGCC_%s_MAX__", name);
> + sprintf (val_name, "__%s_MAX__", float_h_prefix);
> + builtin_define_with_value (macro_name, val_name, 0);
> +
> + macro_name = XALLOCAVEC (char, name_len + sizeof ("__LIBGCC_MIN__"));
> + sprintf (macro_name, "__LIBGCC_%s_MIN__", name);
> + sprintf (val_name, "__%s_MIN__", float_h_prefix);
> + builtin_define_with_value (macro_name, val_name, 0);
I think there's an off-by-one error calculating the allocation sizes for
these three macro names. Note that the code just above uses
sizeof ("__LIBGCC__EXCESS_PRECISION__")
with two underscores between "__LIBGCC" and "EXCESS_PRECISION__",
reflecting that the macro name being constructed has both those
underscores (around the %s expansion of size name_len). I think the three
sizeof calls in the three subsequent allocations likewise need to have
both those underscores present in their arguments.
> diff --git a/libgcc/config/rs6000/_divkc3.c b/libgcc/config/rs6000/_divkc3.c
> index d261f40..f7fa47f 100644
> --- a/libgcc/config/rs6000/_divkc3.c
> +++ b/libgcc/config/rs6000/_divkc3.c
> @@ -37,29 +37,115 @@ see the files COPYING3 and COPYING.RUNTIME respectively.
> If not, see
> #define __divkc3 __divkc3_sw
> #endif
>
> +#define RBIG (__LIBGCC_TF_MAX__ / 2)
> +#define RMIN (__LIBGCC_TF_MIN__)
> +#define RMIN2 (__LIBGCC_TF_EPSILON__)
> +#define RMINSCAL (1 / __LIBGCC_TF_EPSILON__)
> +#define RMAX2 (RBIG * RMIN2)
This file includes quad-float128.h, which does some remapping from TF to
KF depending on __LONG_DOUBLE_IEEE128__.
I think you probably need to have a similar __LONG_DOUBLE_IEEE128__
conditional here. If __LONG_DOUBLE_IEEE128__ is not defined, use
__LIBGCC_KF_* macros instead of __LIBGCC_TF_*; if __LONG_DOUBLE_IEEE128__
is defined, use __LIBGCC_TF_* as above. (Unless the powerpc maintainers
say otherwise.)
--
Joseph S. Myers
[email protected]
