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Re: [PATCH 4/5] Use movq for 64-bit operations
- From: Richard Henderson <rth at twiddle dot net>
- To: Peter Collingbourne <pcc at google dot com>
- Cc: libc-alpha at sourceware dot org
- Date: Mon, 13 May 2013 09:26:20 -0700
- Subject: Re: [PATCH 4/5] Use movq for 64-bit operations
- References: <1368459372-2415-1-git-send-email-pcc at google dot com> <1368459372-2415-5-git-send-email-pcc at google dot com>
On 05/13/2013 08:36 AM, Peter Collingbourne wrote:
> The EXTRACT_WORDS64 and INSERT_WORDS64 macros use movd for a 64-bit
> operation. Somehow gcc manages to turn this into movq, but LLVM won't.
>
> 2013-05-13 Peter Collingbourne <pcc@google.com>
>
> * sysdeps/x86_64/fpu/math_private.h (MOVQ): New macro.
> (EXTRACT_WORDS64) Use where appropriate.
> (INSERT_WORDS64) Likewise.
There's a compatibility issue with older gas where movq wasn't accepted,
but movd was. Current gas allows either. There should be an investigation
as to what gas version contains the fix, and if its older than the minimum
required binutils version.
r~