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Re: define MMX/SSE intrinsics without requiring cmdline isa flags


On Thu, Aug 19, 2010 at 2:11 PM, Michael Meissner
<meissner@linux.vnet.ibm.com> wrote:
> On Wed, Aug 18, 2010 at 05:05:15PM -0700, Xinliang David Li wrote:
>> Hi, I got many complains from the user that gcc's asm intrinsics are
>> hard to use -- because they need to specify command line --mxxx option
>> to use them even though the enclosing function has the right target
>> attribute:
>
>> So the question becomes why not allow the definitions of those
>> wrappers in the first place --- if the user includes the header, he
>> then intends to use them. See attached patch that does this. ?GCC
>> bootstrapping shows that there is NO visible compile time change at
>> all with this patch.
>
> One of the concerns when I did the original work 2 years ago to add target
> support was if the compiler adds all of the builtins, it makes the compiler
> slower at startup because it has to create all of those extra functions (both
> time to create and more importantly, memory requirements for those functions).
>

I did not notice any slowdowns in compiler bootstrap. The observed
memory consumption can increase as large as 300k.

David

> --
> Michael Meissner, IBM
> 5 Technology Place Drive, M/S 2757, Westford, MA 01886-3141, USA
> meissner@linux.vnet.ibm.com
>


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