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From: "rsandifo at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug tree-optimization/97405] ICE in get_or_alloc_expr_for in code
 hoisting with SVE intrinsics
Date: Wed, 14 Oct 2020 07:19:10 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D97405

--- Comment #3 from rsandifo at gcc dot gnu.org <rsandifo at gcc dot gnu.or=
g> ---
(In reply to Richard Biener from comment #2)
> OK, looks like the code expects
>=20
> POLY_INT_CST [16, 16] /[ex] 16
>=20
> to be constant folded - looks like poly_int_binop doesn't handle division
> nor is there a wi::div_trunc for poly_wide_int.
>=20
> This is generated here:
>=20
> Breakpoint 5, copy_reference_ops_from_ref (ref=3D<array_ref 0x7ffff642fa1=
0>,=20
> 891                 /* But record element size in units of the type
> alignment.  */
> 892                 temp.op2 =3D TREE_OPERAND (ref, 3);
> 893                 temp.align =3D eltype->type_common.align;
> 894                 if (! temp.op2)
> 895                   temp.op2 =3D size_binop (EXACT_DIV_EXPR, TYPE_SIZE_=
UNIT
> (eltype),
> 896                                          size_int (TYPE_ALIGN_UNIT
> (eltype)));
>=20
> Hmm, I see that temp.op2 is indeed always needed unless we want to disrupt
> valueization.  copy_reference_ops_from_ref also isn't really allowed to f=
ail.
>=20
> So we absolutely need to be able to fold this EXACT/TRUNC_DIV_EXPR.
>=20
> Richard?
Yeah, EXACT_DIV_EXPR can't in general be folded at compile time
because it wraps differently.  We could perhaps fold it if
TYPE_OVERFLOW_UNDEFINED is true, but by the letter of the law,
we should issue a warning when doing that.

I guess we want something similar to bd8a2482569900a114d631f9c38353d3a96a1d=
85
(And it would be nice if we didn't have too many copies of this code. ;-))=