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Re: Minimum floating-point requirements
- From: "Joseph S. Myers" <joseph at codesourcery dot com>
- To: Steve Munroe <sjmunroe at us dot ibm dot com>
- Cc: Rich Felker <dalias at aerifal dot cx>, Adhemerval Zanella <azanella at linux dot vnet dot ibm dot com>, David Edelsohn <dje dot gcc at gmail dot com>, <libc-alpha at sourceware dot org>
- Date: Mon, 17 Feb 2014 22:50:38 +0000
- Subject: Re: Minimum floating-point requirements
- Authentication-results: sourceware.org; auth=none
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On Mon, 17 Feb 2014, Steve Munroe wrote:
> And why do I keep find packages with -ffloat-store forced on? This is bad
> because PowerPC always had IEEE compliant double and this really hurts
> performance.
I think -ffloat-store should be a no-op on platforms without excess
precision (and for that matter on platforms where the FLT_EVAL_METHOD
definition has excess precision but that's done for consistency with
mistaken float_t / double_t definitions in glibc, rather than because the
platform actually lacks native float/double arithmetic, i.e. S/390).
I.e., GCC should be changed to optimize this.
--
Joseph S. Myers
joseph@codesourcery.com