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r242165 - in /branches/ARM/sve-branch/gcc: expm...
- From: rsandifo at gcc dot gnu dot org
- To: gcc-cvs at gcc dot gnu dot org
- Date: Fri, 11 Nov 2016 17:11:28 -0000
- Subject: r242165 - in /branches/ARM/sve-branch/gcc: expm...
Author: rsandifo
Date: Fri Nov 11 17:11:27 2016
New Revision: 242165
URL: https://gcc.gnu.org/viewcvs?rev=242165&root=gcc&view=rev
Log:
Widening optab cleanup
widening_optab_handler had the comment:
/* ??? Why does find_widening_optab_handler_and_mode attempt to
widen things that can't be widened? E.g. add_optab... */
if (op > LAST_CONV_OPTAB)
return CODE_FOR_nothing;
I think it comes from expand_binop using
find_widening_optab_handler_and_mode for two things: to test whether
a "normal" optab like add_optab is supported for a standard binary
operation and to test whether a "convert" optab is supported for a
widening operation like umul_widen_optab. In the former case from_mode
and to_mode must be the same, in the latter from_mode must be narrower
than to_mode.
For the former case, find_widening_optab_handler_and_mode is only really
testing the modes that are passed in. permit_non_widening must be true
here.
For the latter case, find_widening_optab_handler_and_mode should only
really consider new from_modes that are wider than the original
from_mode and narrower than the original to_mode. Logically
permit_non_widening should be false, since widening optabs aren't
supposed to take operands that are the same width as the destination.
We get away with permit_non_widening being true because no target
would/should define an .md pattern with matching modes.
But really, it seems better for expand_binop to handle these two
cases itself rather than pushing them down. With that change,
find_widening_optab_handler_and_mode is only ever called with
permit_non_widening set to false and is only ever called with
a "proper" convert optab. We then no longer need widening_optab_handler,
we can just use convert_optab_handler directly.
The patch also passes the instruction code down to expand_binop_directly.
This should be more efficient and removes an extra call to
find_widening_optab_handler_and_mode.
Modified:
branches/ARM/sve-branch/gcc/expmed.c
branches/ARM/sve-branch/gcc/expr.c
branches/ARM/sve-branch/gcc/optabs-query.c
branches/ARM/sve-branch/gcc/optabs-query.h
branches/ARM/sve-branch/gcc/optabs.c
branches/ARM/sve-branch/gcc/tree-ssa-math-opts.c