Messages in this thread | | | Date | Thu, 19 Mar 1998 10:25:48 +0100 (CET) | From | Marek Habersack <> | Subject | Re: is gcc 2.8 safe to use yet ? |
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On Wed, 18 Mar 1998, Bernhard Rosenkraenzer wrote:
> On Wed, 18 Mar 1998, Marek Habersack wrote: > > > The XFree86 servers still don't run with a kernel compiled with a gcc 2.8.x > > with the following command line: > > > > -march=pentium -O3 -fomit-frame-pointer <the usual align stuff> > > They do work with a kernel compiled with (gcc-2.8 based) egcs and pgcc... > Any reason not to use those? No, not at all! I just check out all the possibilities. Since the current gcc shares much code with egcc, I assumed they will produce equally good code. I guess I was wrong. Yesterday I was doing some tests and it turned out that gcc 2.8.x generates wrong code when two things are true:
1) the -fomit-frame-pointer flag is used 2) the inlined C functions are used
The optimizer seems to lose sync when a function being inlined contains many local variables - their addresses when traced under gdb appear to be ALWAYS between 0x00 - 0x20 (at the least in the cases I have tested). The problem disappears when the -fno-omit-frame-pointer flag is used.
later, marek --- A bird in the hand makes it awfully hard to blow your nose.
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