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Re: [PATCH] PR 38201: -mfma/-mavx and -msse5/-msse4a don't work together
On Tue, Dec 9, 2008 at 2:20 PM, Andrew Pinski <pinskia@gmail.com> wrote:
> On Tue, Dec 9, 2008 at 1:43 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>> Here is the updated patch with missing new testcases as well as
>> new testcases for "-march=XXX -mavx". When there is a future
>> processor which supports AVX and SSE4a/SSE5, we can
>> update x86 backend to support it properly. Tested on Linux/ia32
>> and Linux/Intel64. OK for trunk?
>
> You still have not explained why you want this patch. I still say we
If we allow "-mfma -msse5", which Fused Multiple and Add instruction
should gcc generate, Intel FMA or AMD SSE5?
> should allow the user to "hang themselves" here and not say they are
It may cause unnecessary bug reports.
> not compatible as who knows what the future processors will be like
> and what a simulator supports.
>
As I said before, if there is such a processor in the future, gcc
should be updated to properly support it. We shouldn't use the
"ancient" gcc on such processor.
--
H.J.