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aarch64/fcsel_1.c contains:
double
f_2 (double a, double b, double c, double d)
{
if (a > b)
return c;
else
return d;
}
which started failing in the GCC 12 timeframe. When it passed,
the RTL had the form:
[A]
(set (reg ret) (reg c))
(set (pc) (if_then_else (gt ...) (label_ref ret) (pc)))
edge to ret, fallthru to else
else:
(set (reg ret) (reg d))
fallthru to ret
ret:
...exit...
i.e. a branch around. Now the RTL has form:
[B]
(set (reg ret) (reg d))
(set (pc) (if_then_else (gt ...) (label_ref then) (pc)))
edge to then, fallthru to ret
ret:
...exit...
then:
(set (reg ret) (reg c))
edge to ret
i.e. a branch out.
Both are valid, of course, and there's no easy way to predict
which we'll get. But ifcvt canonicalises its representation on:
if (cond) goto fallthru else goto non-fallthru
That is, it canoncalises on the branch-around case for half-diamonds.
It therefore wants to invert the comparison in [B] to get:
if (...) goto ret else goto then
But that isn't possible for strict FP gt, so the optimisation fails.
Canonicalising on the branch-around case seems like the wrong choice for
half diamonds. The natural way of expressing a conditional branch is
for the label_ref to be the "then" destination and pc to be the "else"
destination. And the natural choice of condition seems to be the one
under which extra stuff *is* done, rather than the one under which extra
stuff *isn't* done. But that decision goes back at least 20 years and
it doesn't seem like a good idea to change it in stage 4.
This patch instead allows the internal structure to store the
condition in inverted form. For simplicity it handles only
conditional moves, which is the one case that is needed
to fix the known regression. (There are probably unknown
regressions too, but still.)
gcc/
* ifcvt.h (noce_if_info::cond_inverted): New field.
* ifcvt.cc (cond_move_convert_if_block): Swap the then and else
values when cond_inverted is true.
(noce_find_if_block): Allow the condition to be inverted when
handling conditional moves.
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From-SVN: r279813
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PR rtl-optimization/87047
* ifcvt.c (average_cost): New static function. Use it...
(noce_process_if_block): ... here.
testsuite/
* gcc.dg/pr87047.c: New test.
From-SVN: r276466
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From-SVN: r267494
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From-SVN: r256169
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r242550)
PR tree-optimization/79390
* target.h (struct noce_if_info): Declare.
* targhooks.h (default_noce_conversion_profitable_p): Declare.
* target.def (noce_conversion_profitable_p): New target hook.
* ifcvt.h (struct noce_if_info): New type, moved from ...
* ifcvt.c (struct noce_if_info): ... here.
(noce_conversion_profitable_p): Renamed to ...
(default_noce_conversion_profitable_p): ... this. No longer
static nor inline.
(noce_try_store_flag_constants, noce_try_addcc,
noce_try_store_flag_mask, noce_try_cmove, noce_try_cmove_arith,
noce_convert_multiple_sets): Use targetm.noce_conversion_profitable_p
instead of noce_conversion_profitable_p.
* config/i386/i386.c: Include ifcvt.h.
(ix86_option_override_internal): Don't override
PARAM_MAX_RTL_IF_CONVERSION_INSNS default.
(ix86_noce_conversion_profitable_p): New function.
(TARGET_NOCE_CONVERSION_PROFITABLE_P): Redefine.
* config/i386/x86-tune.def (X86_TUNE_ONE_IF_CONV_INSN): Adjust comment.
* doc/tm.texi.in (TARGET_NOCE_CONVERSION_PROFITABLE_P): Add.
* doc/tm.texi: Regenerated.
* gcc.target/i386/pr79390.c: New test.
* gcc.dg/ifcvt-4.c: Use -mtune-ctrl=^one_if_conv_insn for i?86/x86_64.
From-SVN: r246686
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From-SVN: r243994
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From-SVN: r232055
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From-SVN: r219188
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2014-10-22 Andrew MacLeod <amacleod@redhat.com>
* cfgbuild.h: New. Add prototypes for cfgbuild.c.
* cfgcleanup.h: New. Add prototypes for cfgcleanup.c.
* cfgloopmanip.h: New. Add prototypes for cfgloopmanip.c.
* dominance.h: New. Add prototypes for dominance.c.
* cfgloop.h: Move some prototypes/enum to cfgloopmanip.h and include it.
* cfghooks.h: (struct profile_record) Relocate here.
Relocate 2 prototypes from basic-block.h.
* basic-block.h: Move prototypes and struct to new header files.
Include cfgbuild.h, cfgcleanup.h, and dominance.h.
* rtl.h: Move a few prototypes to new header files.
* cfgcleanup.c (merge_memattrs): Make static.
* genopinit.c (main): Add predict.h to list of includes.
* predict.h: Update prototype list to match predict.c.
* predict.c (maybe_hot_count_p): Export.
(cgraph_edge::maybe_hot_p): Move to cgraph.c.
(cgraph_node::optimize_for_size_p): Move to cgraph.h.
* cgraph.h (cgraph_node::optimize_for_size_p): Relocate here.
* cgraph.c (cgraph_edge::maybe_hot_p): Relocate here.
* profile.h: Adjust prototypes.
* ifcvt.h: New. Relocate struct ce_if_block here.
* ifcvt.c: Include ifcvt.h.
* config/frv/frv.c: Include ifcvt.h.
* config/frv/frv-protos.h: Add 'struct' to ce_if_block * parameters.
From-SVN: r216559
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