https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62144
Bug ID: 62144
Summary: "Frame pointer required, but reserved" error with
-fomit-frame-pointer but only with -m32 -O2
Product: gcc
Version: 4.9.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: inline-asm
Assignee: unassigned at gcc dot gnu.org
Reporter: brooks at gcc dot gnu.org
Created attachment 33328
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=33328&action=edit
(Example program)
The following error is unexpected. We use -fomit-frame-pointer to allow us to
reserve a register, but apparently it is required anyway -- but only when
optimization is turned to -O2 and when compiled at -m32.
$ cat t.i
register int x0 asm ("bp");
static char x1[4096];
int strlen (char *);
void x2 ();
void
x3 ()
{
switch (0)
case 0:
x2 (0);
int x4 = strlen (x1);
if (x1[x4] == '\n')
x2 ();
}
$ gcc-archive/trunk/213772/bin/gcc -c t.i -m32 -fomit-frame-pointer
$ gcc-archive/trunk/213772/bin/gcc -c t.i -O1 -m32 -fomit-frame-pointer
$ gcc-archive/trunk/213772/bin/gcc -c t.i -O2 -m32 -fomit-frame-pointer
t.i: In function ‘x3’:
t.i:6:1: error: frame pointer required, but reserved
x3 ()
^
t.i:1:14: note: for ‘x0’
register int x0 asm ("bp");
^
$
Although the examples above use trunk, this also occurs with the 4.9 branch at
the same revision.
