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Re: -mfpmath=387 flag does not prevent gcc from using SSE/SSE2 instructions
- From: Andi Kleen <ak at suse dot de>
- To: Andrew Derrick Balsa <andrebalsa at mailingaddress dot org>
- Cc: gcc-bugs at gcc dot gnu dot org, Andi Kleen <ak at suse dot de>,Andreas Jaeger <aj at suse dot de>
- Date: Fri, 2 May 2003 06:12:59 +0200
- Subject: Re: -mfpmath=387 flag does not prevent gcc from using SSE/SSE2 instructions
- References: <200305020714.50606.andrebalsa@mailingaddress.org>
> I thought the behaviour would be not to generate any SSE/SSE2 instruction with
> this flag. Am I wrong, or could this be a (small) bug?
The x86-64 ABI requires passing floating pointer arguments
in SSE registers. Disabling it is not possible, you would
be incompatible to all libraries.
-Andi