[PATCH PING]Improve induction variable elimination
Bin Cheng
bin.cheng@arm.com
Wed Oct 8 03:35:00 GMT 2014
Hi,
This patch is posted long before in a series of patches at
https://gcc.gnu.org/ml/gcc-patches/2014-07/msg01392.html . Since the
preceding patch is changed according to review comments, also because it's
long time not reviewed, I rebased and updated this patch as attached.
With this patch, spec2k/fp can be improved a little on aarch64.
Bootstrap and test on x86_64 and x86, I am also prepared to fix any
regression in the future. Is it OK?
2014-09-30 Bin Cheng <bin.cheng@arm.com>
* tree-ssa-loop-ivopts.c (iv_nowrap_period)
(nowrap_cand_for_loop_niter_p): New functions.
(period_greater_niter_exit): New function refactored from
may_eliminate_iv.
(difference_cannot_overflow_p): Handle zero offset.
(iv_elimination_compare_lt): New parameter. Check wrapping
behavior for candidate of wrapping type. Handle folded forms
of may_be_zero expression.
(may_eliminate_iv): Call period_greater_niter_exit. Pass new
argument for iv_elimination_compare_lt.
gcc/testsuite/ChangeLog
2014-09-30 Bin Cheng <bin.cheng@arm.com>
* gcc.dg/tree-ssa/ivopts-lt-3.c: New test.
* gcc.dg/tree-ssa/ivopts-lt-4.c: New test.
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