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Re: Turn on -fomit-frame-pointer by default for 32bit x86?
- From: Andi Kleen <andi at firstfloor dot org>
- To: "H.J. Lu" <hjl dot tools at gmail dot com>
- Cc: GCC Patches <gcc-patches at gcc dot gnu dot org>, Uros Bizjak <ubizjak at gmail dot com>
- Date: Fri, 16 Jul 2010 21:35:45 +0200
- Subject: Re: Turn on -fomit-frame-pointer by default for 32bit x86?
- References: <AANLkTikVToxej7rGdy3-vzbyyj1s1RJ7ItM85QEL-OPG@mail.gmail.com>
"H.J. Lu" <hjl.tools@gmail.com> writes:
> [hjl@gnu-6 tmp]$ /usr/gcc-4.5/bin/gcc -m32 -S x.c -O3
> [hjl@gnu-6 tmp]$ cat x.s
> .file "x.c"
> .text
> .globl foo
> .type foo, @function
> foo:
> pushl %ebp
> movl %esp, %ebp
> popl %ebp
> ret
>
> Can we turn on -fomit-frame-pointer by default for 32bit?
I think it's a good idea, but in general one side effect one should
be aware of is that it breaks many profilers with calltrace per sample
support. Those tend to not be able to read unwind tables.
-Andi
--
ak@linux.intel.com -- Speaking for myself only.