extern struct { int a, b, c, d; } v;
extern int w;
void
foo (void)
{
int e1 = v.a;
int e2 = w;
int e3 = v.b;
int e4 = v.c;
int e5 = v.d;
__asm__ volatile ("/* %0 %1 %2 %3 %4 */" : : "nro" (e1), "nro" (e2), "nro"
(e3), "nro" (e4), "nro" (e5));
}
with -O2 -m32 gives:
xlog.i: In function 'foo':
xlog.i:12:3: error: 'asm' operand requires impossible reload
xlog.i:12:3: error: 'asm' operand requires impossible reload
With "nro" is replaced with "nrm", it compiles fine (but, GCC except for latest
trunk might put there side-effects into the unused operand). With "nrm<>"
(which is wrong in this case, the asm would actually need to do ld%U1 %0,%1 or
something similar, but then would be valid) it dies with similar error.
It seems that before reload only when "nrm" is used the asm has (mem (lo_sum
(reg) (symbol_ref))) or (mem (plus (reg) (const_int))) but with "nro" or
"nrm<>" it contains bare (mem (symbol_ref)) or (mem (plus (symbol_ref)
(const_int))) and apparently reload isn't able to deal with that. Not sure if
it is a target powerpc bug, or reload bug, or both. In any case, there
shouldn't be anything impossible here to reload.
I see the ICEs with GCC 4.1, 4.4 and 4.6, so perhaps it is not a regression.
--
Summary: operand requires impossible reload
Product: gcc
Version: 4.6.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: jakub at gcc dot gnu dot org
GCC target triplet: powerpc-linux
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44707
