859966 - (gcc-4.7) Tracking bug for gcc 4.7 switch on linux

Status: RESOLVED FIXED

(Firefox Build System :: General, defect)

Comment 1

[Gregory Szorc [:gps]]

Are any large, stable projects (perhaps even distros) using 4.7? Put another way, do we risk subjecting our users to undiscovered bugs in a newer compiler version because we're an early adopter? i.e. I'd prefer we let someone else "QA" the compiler before we switch to it.

Since 4.7 was released only a few weeks ago, I suspect the answer is "no, nobody else is largely using 4.7 yet." So, why are we risking this transition?

Comment 2

[Gregory Szorc [:gps]]

Oh wait - it was released in 2012. Disregard the 2nd paragraph. The original point still remains though.

Comment 3

[Mike Hommey [:glandium]]

gcc 4.7 has been used to build Firefox on all the main distros for a while.
And the version that was released a few weeks ago is 4.8 :)

Comment 4

[Mike Hommey [:glandium]]

I suspect most Mozilla developers building on Linux are also using gcc >= 4.7.

Comment 5

[Trevor Saunders (:tbsaunde)]

for whatever its worth I believe gcc 4.5 is officially not supported anymore either.

Comment 6

[Timothy Nikkel (:tnikkel)]

And it's not like gcc 4.5 is bug free either http://mxr.mozilla.org/mozilla-central/source/gfx/2d/convolver.cpp?force=1#158

Comment 7

[Mike Hommey [:glandium]]

Attachment: Switch linux builds to gcc 4.7.2

Comment 8

[Gregory Szorc [:gps]]

Comment on attachment 750513 [details] [diff] [review]
Switch linux builds to gcc 4.7.2

Review of attachment 750513 [details] [diff] [review]:
-----------------------------------------------------------------

This is mostly a rubber stamp. I trust from the discussion on dev-platform and elsewhere that everyone is OK with this.

Comment 9

[Mike Hommey [:glandium]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/8d46dcc704d7

Comment 10

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/8d46dcc704d7

Comment 11

[Boris Zbarsky [:bzbarsky]]

This seems to have been a noticeable performance improvement on Dromaeo: 9.5% faster on 32-bit Dromaeo-CSS, 5.5% faster on 64-bit Dromaeo-CSS, 2.5% faster on 32-bit Dromaeo-DOM.

Comment 12

[Gregory Szorc [:gps]]

This *may* have regressed PGO build times by nearly an hour. Investigation in bug 893078.