RE: [PING][Patch] Add support for IEEE-conformant versions of scalar fmin* and fmax*

[David Sherwood]

Hi All,

For what it's worth I have uploaded a new patch that changes the name
from STRICT_FMIN/MAX to just FMIN/FMAX, although I realise that this
discussion has not yet been resolved. I have also added scheduling
attributes to the aarch64 instructions.

Regards,
David Sherwood.

ChangeLog:

2015-08-28  David Sherwood  <david.sherw...@arm.com>

    gcc/
        * builtins.c (integer_valued_real_p): Add FMIN_EXPR and FMAX_EXPR.
        (fold_builtin_fmin_fmax): For strict math, convert builtins fmin and
        fmax to FMIN_EXPR and FMIN_EXPR, respectively.
        * expr.c (expand_expr_real_2): Add FMIN_EXPR and FMAX_EXPR.
        * fold-const.c (const_binop): Likewise.
        (fold_binary_loc, tree_binary_nonnegative_warnv_p): Likewise.
        (tree_binary_nonzero_warnv_p): Likewise.
        * optabs.h (fminmax_support): Declare.
        * optabs.def: Add new optabs fmax_optab/fmin_optab.
        * optabs.c (optab_for_tree_code): Return new optabs for FMIN_EXPR and
        FMAX_EXPR.
        (fminmax_support): New function.
        * real.c (real_arithmetic): Add FMIN_EXPR and FMAX_EXPR.
        * tree.def: Likewise.
        * tree.c (associative_tree_code, commutative_tree_code): Likewise.
        * tree-cfg.c (verify_expr): Likewise.
        (verify_gimple_assign_binary): Likewise.
        * tree-inline.c (estimate_operator_cost): Likewise.
        * tree-pretty-print.c (dump_generic_node, op_code_prio): Likewise.
        (op_symbol_code): Likewise.
        * config/aarch64/aarch64.md: New pattern.
        * config/aarch64/aarch64-simd.md: Likewise.
        * config/aarch64/iterators.md: New unspecs, iterators.
        * config/arm/iterators.md: New iterators.
        * config/arm/unspecs.md: New unspecs.
        * config/arm/neon.md: New pattern.
        * config/arm/vfp.md: Likewise.
        * doc/generic.texi: Add FMAX_EXPR and FMIN_EXPR.
        * doc/md.texi: Add fmin and fmax patterns.
    gcc/testsuite
        * gcc.target/aarch64/fmaxmin.c: New test.
        * gcc.target/arm/fmaxmin.c: New test.


> -----Original Message-----
> From: Richard Biener [mailto:richard.guent...@gmail.com]
> Sent: 19 August 2015 14:41
> To: Richard Biener; David Sherwood; GCC Patches; Richard Sandiford
> Subject: Re: [PING][Patch] Add support for IEEE-conformant versions of scalar 
> fmin* and fmax*
> 
> On Wed, Aug 19, 2015 at 3:06 PM, Richard Sandiford
> <richard.sandif...@arm.com> wrote:
> > Richard Biener <richard.guent...@gmail.com> writes:
> >> As an additional point for many math functions we have to support errno
> >> which means, like, BUILT_IN_SQRT can be rewritten to SQRT_EXPR
> >> only if -fno-math-errno is in effect.  But then code has to handle
> >> both variants for things like constant folding and expression combining.
> >> That's very unfortunate and something we want to avoid (one reason
> >> the POW_EXPR thing didn't fly when I tried).  STRICT_FMIN/MAX_EXPR
> >> is an example where this doesn't apply, of course (but I detest the name,
> >> just use FMIN/FMAX_EXPR?).  Still you'd need to handle both,
> >> FMIN_EXPR and BUILT_IN_FMIN, in code doing analysis/transform.
> >
> > Yeah, but match.pd makes that easy, right? ;-)
> 
> Sure, but that only addresses stmt combining, not other passes.  And of course
> it causes {gimple,generic}-match.c to become even bigger ;)
> 
> Richard.

fmaxmin.patch
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