https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79807
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2017-03-02
CC|jakub at redhat dot com |jakub at gcc dot
gnu.org,
| |uros at gcc dot gnu.org
Target Milestone|--- |5.5
Summary|ICE in extract_insn, at |[5/6/7 Regression] ICE in
|recog.c:2311 (error: |extract_insn, at
|unrecognizable insn) |recog.c:2311 (error:
| |unrecognizable insn)
Ever confirmed|0 |1
--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
This is not related to PR79568 in any way.
I think it started with r178132.
Short testcase -O0 -mavx -ffloat-store:
typedef double __m128d __attribute__ ((__vector_size__ (16), __may_alias__));
typedef double __m256d __attribute__ ((__vector_size__ (32), __may_alias__));
typedef double __v4df __attribute__ ((__vector_size__ (32)));
__m128d
foo (__m256d __A)
{
return (__m128d) __builtin_ia32_pd_pd256 ((__v4df)__A);
}
I think the problem is that tons of sse.md instructions accept memory in both
output operand predicate and some input operand predicate, but then have
conditions like:
&& !(MEM_P (operands[0]) && MEM_P (operands[1]))
or
&& (register_operand (operands[0], <MODE>mode)
|| register_operand (operands[1], <MODE>mode))
But, when this is expanded through ix86_expand_*_builtin,
(ix86_expand_args_builtin in particular in this case), we only care about the
predicates, not the condition.
And we have:
if (rmode == VOIDmode || rmode == tmode)
{
if (optimize
|| target == 0
|| GET_MODE (target) != tmode
|| !insn_p->operand[0].predicate (target, tmode))
target = gen_reg_rtx (tmode);
real_target = target;
}
else
{
real_target = gen_reg_rtx (tmode);
target = lowpart_subreg (rmode, real_target, tmode);
}
and then:
/* If we aren't optimizing, only allow one memory operand to
be generated. */
if (memory_operand (op, mode))
num_memory++;
...
if (optimize || !match || num_memory > 1)
op = copy_to_mode_reg (mode, op);
So, for -O0, we can end up with both the target/real_target being MEM as well
as one of the operands.
The big question is if there are any insns we care for -O0 to have MEMs in both
output and input operands. If not, I have a patch.
