remove SSE runtime check if we know it's supported at compile time

If we know that the target platform supports SSE2 or SSSE3 at compile time, then there is no need to do dynamic check to be supported.

[reed1, 2012-06-21 17:28:24]

__X86_USE_SSE2

Who defines this symbol? Which compilers? I didn't see it on a quick googler
search.

[Lei, 2012-07-02 07:46:04]

Hi reed1, sorry for the late reply. Actually the flag is USE_SSE2. We added this
flag in android specific makefile of SKIA in order to explicitly distinguish
from arm. I will change to USE_SSE2 flag.

[Lei, 2012-07-02 07:58:49]

updated patch

[reed1, 2012-07-02 14:40:04]

I just added SK_CPU_SSE_LEVEL to SkPreConfig.h. Can you use that instead (and
trigger that on the android build)? That way we can test it on android and
desktops.

[Lei, 2012-07-03 01:53:04]

No problem. I will modify the makefile (Android.mk) a little bit to trigger this
flag on the android build. Then I may need to upstream this makefile to Android
code base.

[Lei, 2012-07-03 01:53:24]

updated the patch after changing the flag from USE_SSE2 to SK_CPU_SSE_LEVEL

[reed1, 2012-07-03 12:11:52]

You need to check that the defined level is >= the level when SSE2 is support.

#if SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSE2
...
#endif

[Lei, 2012-07-04 04:07:11]

Sure. I also added SSSE3 check at compile time, and this may be beneficial on
desktop. Meanwhile, I saw you added SSE_LEVEL defines in SkPreConfig.h. It seems
that there is some minor mistakes. If defined SSSE3, SSE_LEVEL will be equal to
SK_CPU_SSE_LEVEL_SSSE3 not SK_CPU_SSE_LEVEL_SSE2:)

[Lei, 2012-07-04 04:08:38]

remove runtime check of SSE2 and SSE3 if we know it's supported at compile time

[reed1, 2012-07-09 13:03:28]

Thanks for catching my bug in SkPreConfig.h. I have tried to fix that, and have
added the check for 64bit x86, so that we automatically set SK_CPU_SSE_LEVEL to
at least SSE2 if we're on 64bit. This should simplify your CL.

[Lei, 2012-07-16 07:43:50]

Hi Reed, thanks for your effort. Do I need to change anything? If it's OK, can
we merge it? Thanks very much.

[reed1, 2012-07-16 16:08:03]

landed in rev. 4622. Please close this issue.

[Lei, 2012-07-17 04:05:26]

Thanks, reed~