[PATCH] Omit frame pointer and fix %ebp by default on x86 (take 3)

Jakub Jelinek jakub@redhat.com
Mon Aug 16 19:28:00 GMT 2004


On Mon, Aug 16, 2004 at 12:18:21PM -0600, Roger Sayle wrote:
> 
> On Mon, 16 Aug 2004, Jakub Jelinek wrote:
> > Neither do I understand this.
> 
> Don't worry about too much.  Clearly you're not the only one that's
> having difficulty grasping these advanced new concepts :>
> 
> This patch is not designed to make backtrace work for every frame,
> only to stop it from failing.

How is that better from making -fomit-frame-pointer
-fasynchronous-unwind-tables the default.
My guess is that big part of the -fno-omit-frame-pointer
-> -fomit-frame-pointer speedup comes from being able to use
another register on very register starved architecture
and backtrace () is useless with -fomit-frame-pointer -ffixed-ebp
anyway unless it can use unwind info.

	Jakub



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