https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113622
--- Comment #15 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Jakub Jelinek from comment #11)
> I think it is most important we don't ICE and generate correct code. I
> doubt this is used too much in real-world code, otherwise it would have been
> reported years ago, so how efficient it will be is less important.
We do spill on the read side already. On the write side the ICE is because
of r0-71337-g1e188d1e130034. Note we're spilling parts of bitpos to offset:
/* Otherwise, split it up. */
if (offset)
{
/* Avoid returning a negative bitpos as this may wreak havoc later. */
if (!bit_offset.to_shwi (pbitpos) || maybe_lt (*pbitpos, 0))
{
*pbitpos = num_trailing_bits (bit_offset.force_shwi ());
poly_offset_int bytes = bits_to_bytes_round_down (bit_offset);
offset = size_binop (PLUS_EXPR, offset,
build_int_cst (sizetype, bytes.force_shwi ()));
}
*poffset = offset;
but it can also be large positive when the bit amount doesn't fit a HWI.
The flow of 'to' expansion is a bit awkward, but the following properly
spills in case of variable offset and non-MEM_P:
diff --git a/gcc/expr.cc b/gcc/expr.cc
index ee822c11dce..f54d0b1474e 100644
--- a/gcc/expr.cc
+++ b/gcc/expr.cc
@@ -6061,6 +6061,7 @@ expand_assignment (tree to, tree from, bool nontemporal)
to_rtx = adjust_address (to_rtx, BLKmode, 0);
}
+ rtx stemp = NULL_RTX, old_to_rtx = NULL_RTX;
if (offset != 0)
{
machine_mode address_mode;
@@ -6070,9 +6071,24 @@ expand_assignment (tree to, tree from, bool nontemporal)
{
/* We can get constant negative offsets into arrays with broken
user code. Translate this to a trap instead of ICEing. */
- gcc_assert (TREE_CODE (offset) == INTEGER_CST);
- expand_builtin_trap ();
- to_rtx = gen_rtx_MEM (BLKmode, const0_rtx);
+ if (TREE_CODE (offset) == INTEGER_CST)
+ {
+ expand_builtin_trap ();
+ to_rtx = gen_rtx_MEM (BLKmode, const0_rtx);
+ }
+ /* Else spill for variable offset to the destination. */
+ else
+ {
+ gcc_assert (!TREE_CODE (from) == CALL_EXPR
+ && COMPLETE_TYPE_P (TREE_TYPE (from))
+ && (TREE_CODE (TYPE_SIZE (TREE_TYPE (from)))
+ != INTEGER_CST));
+ stemp = assign_stack_temp (GET_MODE (to_rtx),
+ GET_MODE_SIZE (GET_MODE
(to_rtx)));
+ emit_move_insn (stemp, to_rtx);
+ old_to_rtx = to_rtx;
+ to_rtx = stemp;
+ }
}
offset_rtx = expand_expr (offset, NULL_RTX, VOIDmode, EXPAND_SUM);
@@ -6305,6 +6321,9 @@ expand_assignment (tree to, tree from, bool nontemporal)
bitregion_start, bitregion_end,
mode1, from, get_alias_set (to),
nontemporal, reversep);
+ /* Move the temporary storage back to the non-MEM_P. */
+ if (stemp)
+ emit_move_insn (old_to_rtx, stemp);
}
if (result)
