Bug 7765

Summary:	gcc 3.2 on ppc compiles unreliably using -O3 optimization
Product:	Gentoo Linux	Reporter:	Kevyn Shortell (RETIRED) <trance>
Component:	Current packages	Assignee:	Kevyn Shortell (RETIRED) <trance>
Status:	VERIFIED FIXED
Severity:	critical	CC:	mguertin
Priority:	Highest
Version:	unspecified
Hardware:	PPC
OS:	Linux
Whiteboard:
Package list:		Runtime testing required:	---

Description Kevyn Shortell (RETIRED) gentoo-dev

2002-09-10 15:24:16 UTC

In using -O3 flags with gcc 3.2 on ppc, I've noticed inconsistant results in 
compiling. most things build, random things fail.

Doing a stage1 build, parts of emerge system just don't get compiled, when you 
manually try to compile the parts that were missed, some things segfault. 
This appears to be Altivec/74xx related, as Gerk reports it doesn't happen on 
75x series CPUs

Until this is nailed down to something more specific than -O3 sucks, I'd 
recommend we don't use -O3 as part of the default make.conf

Comment 1 Mark Guertin 2002-09-10 15:36:30 UTC

I will make adjustments for this tonight, and wholeheartedly agree that -O3 is a
bad thing for ppc and gcc 3.2 final (funny thing is it worked great for gcc
3.2_pre) ?

Comment 2 Jim Bray 2003-01-30 22:53:40 UTC

  I have discovered an architecture-independent bug in current Gentoo
gcc that might be what you are seeing here:

http://bugs.gentoo.org/show_bug.cgi?id=14699