HAO CHEN GUI <guih...@linux.ibm.com> writes:
> Hi,
> This patch adds an optab for __builtin_isfinite. The finite check can be
> implemented on rs6000 by a single instruction. It needs an optab to be
> expanded to the certain sequence of instructions.
>
> The subsequent patches will implement the expand on rs6000.
>
> Compared to previous version, the main change is to specify acceptable
> modes for the optab.
> https://gcc.gnu.org/pipermail/gcc-patches/2024-May/652170.html
>
> Bootstrapped and tested on x86 and powerpc64-linux BE and LE with no
> regressions. Is this OK for trunk?
>
> Thanks
> Gui Haochen
>
> ChangeLog
> optab: Add isfinite_optab for isfinite builtin
>
> gcc/
> * builtins.cc (interclass_mathfn_icode): Set optab to isfinite_optab
> for isfinite builtin.
> * optabs.def (isfinite_optab): New.
> * doc/md.texi (isfinite): Document.
>
>
> patch.diff
> diff --git a/gcc/builtins.cc b/gcc/builtins.cc
> index f8d94c4b435..b8432f84020 100644
> --- a/gcc/builtins.cc
> +++ b/gcc/builtins.cc
> @@ -2459,8 +2459,9 @@ interclass_mathfn_icode (tree arg, tree fndecl)
> errno_set = true; builtin_optab = ilogb_optab; break;
> CASE_FLT_FN (BUILT_IN_ISINF):
> builtin_optab = isinf_optab; break;
> - case BUILT_IN_ISNORMAL:
> case BUILT_IN_ISFINITE:
> + builtin_optab = isfinite_optab; break;
> + case BUILT_IN_ISNORMAL:
> CASE_FLT_FN (BUILT_IN_FINITE):
> case BUILT_IN_FINITED32:
> case BUILT_IN_FINITED64:
> diff --git a/gcc/doc/md.texi b/gcc/doc/md.texi
> index 5730bda80dc..67407fad37d 100644
> --- a/gcc/doc/md.texi
> +++ b/gcc/doc/md.texi
> @@ -8557,6 +8557,15 @@ operand 2, greater than operand 2 or is unordered with
> operand 2.
>
> This pattern is not allowed to @code{FAIL}.
>
> +@cindex @code{isfinite@var{m}2} instruction pattern
> +@item @samp{isfinite@var{m}2}
> +Set operand 0 to nonzero if operand 1 is a finite @code{SFmode},
> +@code{DFmode}, or @code{TFmode} floating point number and to 0
> +otherwise.
This has probably already been discussed, sorry, but how about defining
the optab to return a strict 0/1 result, rather than just zero/nonzero?
I realise that's stricter than the underlying math.h routines, but it
would in principle avoid the need to expand extra instructions in
a setcc-like operation.
Richard
> +
> +If this pattern @code{FAIL}, a call to the library function
> +@code{isfinite} is used.
> +
> @end table
>
> @end ifset
> diff --git a/gcc/optabs.def b/gcc/optabs.def
> index ad14f9328b9..dcd77315c2a 100644
> --- a/gcc/optabs.def
> +++ b/gcc/optabs.def
> @@ -352,6 +352,7 @@ OPTAB_D (fmod_optab, "fmod$a3")
> OPTAB_D (hypot_optab, "hypot$a3")
> OPTAB_D (ilogb_optab, "ilogb$a2")
> OPTAB_D (isinf_optab, "isinf$a2")
> +OPTAB_D (isfinite_optab, "isfinite$a2")
> OPTAB_D (issignaling_optab, "issignaling$a2")
> OPTAB_D (ldexp_optab, "ldexp$a3")
> OPTAB_D (log10_optab, "log10$a2")
