https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115405
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |rguenth at gcc dot gnu.org
--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
The IL before expansion doesn't have a VCE, just
MEM[(_BitInt(17) *)&b]
where b has unsigned _BitInt(17) type.
Then
/* Handle expansion of non-aliased memory with non-BLKmode. That
might end up in a register. */
if (mem_ref_refers_to_non_mem_p (exp))
{
poly_int64 offset = mem_ref_offset (exp).force_shwi ();
base = TREE_OPERAND (base, 0);
poly_uint64 type_size;
if (known_eq (offset, 0)
&& !reverse
&& poly_int_tree_p (TYPE_SIZE (type), &type_size)
&& known_eq (GET_MODE_BITSIZE (DECL_MODE (base)), type_size))
return expand_expr (build1 (VIEW_CONVERT_EXPR, type, base),
target, tmode, modifier);
in expr.cc turns that into a VCE.
And VCE doesn't really EXTEND_BITINT because the upper bits generally in a VCE
are undefined.
Finally the NOP_EXPR expansion sees a SImode signed _BitInt(17) extension to
SImode 32-bit int and assumes for something in an automatic var to be already
properly extended.
Dunno where the bug is, whether trying to use VCE for the _BitInt cases as in
the snippet above, or VCE not doing EXTEND_BITINT, or NOP_EXPR handling that
should extend even in this case.
