On 3/22/24 11:45 PM, Li, Pan2 wrote:
Thanks Jeff for comments.
As Richi noted using validate_subreg here isn't great. Does it work to
factor out this code from extract_low_bits
if (!int_mode_for_mode (src_mode).exists (&src_int_mode)
|| !int_mode_for_mode (mode).exists (&int_mode))
return NULL_RTX;
if (!targetm.modes_tieable_p (src_int_mode, src_mode))
return NULL_RTX;
if (!targetm.modes_tieable_p (int_mode, mode))
return NULL_RTX;
And use that in the condition (and in extract_low_bits rather than
duplicating the code)?
It can solve the ICE but will forbid all vector modes goes gen_lowpart.
Actually only the vector mode size is less than reg nature size will trigger
the ICE.
Thus, how about just add one more condition before goes to gen_lowpart as below?
Feel free to correct me if any misunderstandings. 😉!
diff --git a/gcc/dse.cc b/gcc/dse.cc
index edc7a1dfecf..258d2ccc299 100644
--- a/gcc/dse.cc
+++ b/gcc/dse.cc
@@ -1946,7 +1946,9 @@ get_stored_val (store_info *store_info, machine_mode
read_mode,
copy_rtx (store_info->const_rhs));
else if (VECTOR_MODE_P (read_mode) && VECTOR_MODE_P (store_mode)
&& known_le (GET_MODE_BITSIZE (read_mode), GET_MODE_BITSIZE (store_mode))
- && targetm.modes_tieable_p (read_mode, store_mode))
+ && targetm.modes_tieable_p (read_mode, store_mode)
+ /* It's invalid in validate_subreg if read_mode size is < reg natural. */
+ && known_ge (GET_MODE_SIZE (read_mode), REGMODE_NATURAL_SIZE (read_mode)))
read_reg = gen_lowpart (read_mode, copy_rtx (store_info->rhs));
else
read_reg = extract_low_bits (read_mode, store_mode,
So how about this. I'll ack this for the trunk, but not for gcc-14 (at
this time). We can revisit for gcc-14 after it's been on the trunk a
bit. Realistically that likely means gcc-14.2 at the end of the summer
rather than gcc-14.1 which is due in roughly a week.
Jeff
