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SubjectRe: BUG: GCC-4.4.x changes the function frame on some functions
On 11/19/09 14:14, H. Peter Anvin wrote:
> Hence a new unconstrained option...
>
Not arguing against it, just noting there are targets where after the
prologue mcount is mandated. There's certainly hooks in GCC to do it
both ways and if there's no clear need to use after-prologue on
x86-linux, then before-prologue seems reasonable to me.

It's also the case that aligning stacks on the x86 and the poor code
generated when used with profiling is an interaction I doubt anyone has
looked at until now. The result is definitely ugly and inefficient --
and there's something to be said for cleaning that up and at least
marginally reducing the overhead of profiling.

Having said all that, I don't expect to personally be looking at the
problem, given the list of other codegen issues that need to be looked
at (reload in particular), profiling/stack interactions would be around
87 millionth on my list.

jeff



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