-mieee on alpha? Yes or no?

[Lupin_the_3rd]

According to Gentoo Alpha porting guide, (here: http://www.gentoo.org/proj/en/base/alpha/doc/alpha-porting-guide.xml#doc_chap4 ) it says that on EV6 and better, the -mieee CFLAG is not required. It defines the flag as enabling "software assisted floating point at compile time". Since the EV6 and better processors have full IEEE floating point arithmetic implemented in hardware, it makes sense that the flag is not required.

Seemingly contradictory, over at the Gentoo Safe CFLAGS page, (here: http://gentoo-wiki.com/Safe_Cflags#Alpha_ev67 ) the EV67 example does include the -mieee flag! Wouldn't it be safer to omit an unnecessary CFLAG?

So the purpose of this post is two fold:

1: Is there any benefit to using (or not using) the -mieee flag on EV6 processors? Or does it generate the exact same code either way (on EV6)?

2: How many of you have EV6 (or better) and ARE using the -mieee flag? And why?
_________________
Compaq XP1000 Alpha EV67 667Mhz w/ 2GB ECC
32bit PCI: ATI Radeon 9100 (DRI works!)
32bit PCI: Generic Firewire 400 card
64bit PCI: BCM5703 Gig-E (Compaq NC7771)
64bit PCI: Sil3124 SATA w/ mdadm RAID1 (pair of WD VelociRaptors)

[desultory]

It is enabled by default.

[sae]

In the case of EV6, it has to do with it flushing denormalized numbers to zero... In some cases it is OK, but in others not, you will have to look into this yourself, I am not a numerical computation guru...
_________________
"The purpose of computing is insight, not numbers." - Hamming
- AMD athlon 64x2 4600+, 3GB -