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Re: [PATCH] aarch64 sim fcsel bug fix
- From: Nick Clifton <nickc at redhat dot com>
- To: Jim Wilson <jim dot wilson at linaro dot org>, gdb-patches at sourceware dot org
- Date: Tue, 3 Jan 2017 14:39:51 +0000
- Subject: Re: [PATCH] aarch64 sim fcsel bug fix
- Authentication-results: sourceware.org; auth=none
- References: <CABXYE2XHHk26_VGK7o936bvQ591oaOfGyMiwPwRg5ELxUVEMwg@mail.gmail.com>
Hi Jim,
> The fcsel instruction is storing source register numbers in the
> destination register, instead of source register contents. There are
> missing calls to fetch the contents of the source registers.
>
> While looking at this, I ran into the problem that when an FP register
> changes from plus zero to minus zero, or vice versa, I don't get any
> output with --trace-register. The GCC C testcase I was looking at
> happened to be testing support for signed zeros, and the source
> register number happened to be zero, so I needed this to work right to
> see what was going wrong. I added signbit calls to catch this case.
>
> The testcase fails without the patch, and works with the patch. The
> GCC C testsuite unexpected failures drop from 2473 to 2416.
Approved - please apply - and thanks for all of these patches!
Cheers
Nick