Hi all,
The patch implements the division opitmizations discussed in
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71026 .
The implemented change differs slightly from the
proposed one in that we re-associate:
C / x comparison 0.0 -> x comparison' 0.0
Where C is any constant and comparison' is changed as
appropriate if C is negative.
The implementations also removes the division from:
x / C comparison 0.0 -> x comparison' 0.0
Where again, comparison' is changed as appropriate if C is
negative.
We also change the association of
x / (y * C) -> (x / C) / y
If C is a constant. All of the above require
-funsafe-math-optimizations.
We also change:
x / (- y) -> (-x) / y
Which requires -fno-trapping-math.
Bootstrapped and regtested (with part 2 of this patch) on aarch64.
OK for trunk?
(Apologies if the recipients in the 'to' field received this twice,
I accidentally sent this from an email gcc-patches doesn't accept)
Jackson
gcc/
2017-08-03 Jackson Woodruff <jackson.woodr...@arm.com>
PR 71026/tree-optimization
* match.pd: New patterns.
gcc/testsuite
2017-08-03 Jackson Woodruff <jackson.woodr...@arm.com>
PR 71026/tree-optimization
* gcc.dg/associate_comparison_1.c: New.
* gcc.dg/associate_division_2.c: New.
