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Re: [PR72835] Incorrect arithmetic optimization involving bitfield arguments
- From: Jakub Jelinek <jakub at redhat dot com>
- To: kugan <kugan dot vivekanandarajah at linaro dot org>
- Cc: "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>, Richard Biener <richard dot guenther at gmail dot com>
- Date: Tue, 9 Aug 2016 23:46:17 +0200
- Subject: Re: [PR72835] Incorrect arithmetic optimization involving bitfield arguments
- Authentication-results: sourceware.org; auth=none
- References: <0a1eaaf8-3ede-cd56-ffb5-40b25f94e46e@linaro.org> <98613cff-7c48-1a56-0014-6d87c35a8f26@linaro.org>
- Reply-to: Jakub Jelinek <jakub at redhat dot com>
On Wed, Aug 10, 2016 at 07:42:25AM +1000, kugan wrote:
> There was no new regression while testing. I also moved the testcase from
> gcc.dg/torture/pr72835.c to gcc.dg/tree-ssa/pr72835.c. Is this OK for trunk?
This looks strange. The tree-ssa-reassoc.c code has been trying to never
reuse SSA_NAMEs if they would hold a different value.
So there should be no resetting of flow sensitive info needed.
> gcc/testsuite/ChangeLog:
>
> 2016-08-10 Kugan Vivekanandarajah <kuganv@linaro.org>
>
> PR tree-optimization/72835
> * gcc.dg/tree-ssa/pr72835.c: New test.
>
> gcc/ChangeLog:
>
> 2016-08-10 Kugan Vivekanandarajah <kuganv@linaro.org>
>
> PR tree-optimization/72835
> * tree-ssa-reassoc.c (rewrite_expr_tree): Reset value_range of LHS when
> operands are changed.
> (rewrite_expr_tree_parallel): Likewise.
Jakub