Apply performance options

[rudi]

Since we need to use any piece of performance we can get and we don't have to support i386 CPUs, I suggest to let qmake generate the compiler options (for GCC4.x):

-march=i486 -mtune=generic

Don't expect wonders from that, but a small speed gain can be measured. The down side is, that the created code grows a bit in size.

[Dmitry A. Kuminov]

This needs to be tested using the BLIT test (see the test result table in #101). Once I get numbers and these numbers demonstrate a noticeable performance boost, I will enable it.

[Silvan Scherrer]

speed w/o the above options:

driver/mode	NO_DIVE	DIVE=BLIT	DIVE=FB	DIVE=FBSWM
Panorama/32bit (16M)	30258	41744	47460	44459

speed with the above options:

driver/mode	NO_DIVE	DIVE=BLIT	DIVE=FB	DIVE=FBSWM
Panorama/32bit (16M)	31032	43670	48940	47789

[Dmitry A. Kuminov]

Not that bad. (The FBSWM test is probably not in the line because it depends on where your mouse is and how intensively you move it). I think it's worth doing it. I don't think there is anybody running an i386 PC and wanting to use Qt4.

[Silvan Scherrer]

i agree with the above and moved the ticket to 4.6.2 milestone.

[Dmitry A. Kuminov]

Done in r720.