https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96017
--- Comment #14 from Surya Kumari Jangala ---
Instead of using a non-volatile register to hold the value of foo, a volatile
register (r9) is assigned to hold foo. This avoids setting up the stack frame
in the fast path.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96017
--- Comment #13 from Surya Kumari Jangala ---
With the patch at
https://gcc.gnu.org/pipermail/gcc-patches/2023-October/631849.html, the
testcase gets shrink wrapped. This is the assembly produced:
addis 2,12,.TOC.-.LCF0@ha
addi
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96017
Richard Biener changed:
What|Removed |Added
Target Milestone|11.2|---
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96017
Jakub Jelinek changed:
What|Removed |Added
Target Milestone|11.0|11.2
--- Comment #12 from Jakub Jelinek
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96017
--- Comment #11 from Segher Boessenkool ---
(In reply to Peter Bergner from comment #9)
> (In reply to Peter Bergner from comment #8)
> > At first, I thought that split_live_ranges_for_shrink_wrap() split this
> > nicely, but what I found is
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96017
--- Comment #10 from Segher Boessenkool ---
(In reply to Peter Bergner from comment #6)
> Right, that's why we need to add the copies before RA, so we don't have to
> look for unused regs. But we don't want to add the copies too early just
>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96017
--- Comment #9 from Peter Bergner ---
(In reply to Peter Bergner from comment #8)
> At first, I thought that split_live_ranges_for_shrink_wrap() split this
> nicely, but what I found is that IRA assigned a volatile register to a
> pseudo that is
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96017
--- Comment #8 from Peter Bergner ---
Interesting, if I rewrite the test case so that foo is a parameter and not a
global var, then we get the code we want:
extern void slowpath(int *);
int
test (int *val, int foo)
{
int ret = foo;
if
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96017
--- Comment #7 from Peter Bergner ---
(In reply to Peter Bergner from comment #6)
> There is ira.c:split_live_ranges_for_shrink_wrap(). I'll have a look to see
> why it's not catching this test case.
So it looks like it only splits pseudos
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96017
--- Comment #6 from Peter Bergner ---
(In reply to Segher Boessenkool from comment #5)
> But it is r31 already before
> shrink-wrapping -- we need some renaming / copying of registers (like
> in Peter's code) to get rid of it. In an example
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96017
Segher Boessenkool changed:
What|Removed |Added
Last reconfirmed||2020-07-01
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96017
--- Comment #4 from Peter Bergner ---
To be pedantic, "val" is assigned r3, the incoming arg reg. The compiler
temporary that holds "*val" is assigned r9 which is a volatile register. The
only non-volatile in use is r31 which was assigned to
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96017
--- Comment #3 from Nicholas Piggin ---
This is possibly a more targeted and simpler test case for at least one of the
problems in bug 84443. I would like to re-test that case after this one is
solved if it's not an obvious duplicate.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96017
--- Comment #2 from Bill Schmidt ---
Nick reports same behavior at -O3.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96017
Bill Schmidt changed:
What|Removed |Added
Target Milestone|9.4 |11.0
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96017
Bill Schmidt changed:
What|Removed |Added
CC||segher at gcc dot gnu.org,
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