https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121308
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed| |2025-07-30
Keywords| |build
Ever confirmed|0 |1
Assignee|unassigned at gcc dot gnu.org |pinskia at gcc dot
gnu.org
Status|UNCONFIRMED |ASSIGNED
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
diff --git a/gcc/simplify-rtx.cc b/gcc/simplify-rtx.cc
index 442da9f40fa..a83c0343e78 100644
--- a/gcc/simplify-rtx.cc
+++ b/gcc/simplify-rtx.cc
@@ -8341,7 +8341,22 @@ simplify_context::simplify_subreg (machine_mode
outermode, rtx op,
rtx op0 = simplify_subreg (outermode, XEXP (op, 0), innermode, byte);
rtx op1 = simplify_subreg (outermode, XEXP (op, 1), innermode, byte);
if (op0 && op1)
+{
+ fprintf (stderr, "op0 = ");
+ print_rtl (stderr, op0);
+ fprintf (stderr, "\n");
+ fprintf (stderr, "op1 = ");
+ print_rtl (stderr, op1);
+ fprintf (stderr, "\n");
return simplify_gen_binary (GET_CODE (op), outermode, op0, op1);
+}
+ }
+ /* Attempt to simplify WORD_MODE SUBREGs of unary bitwise expression. */
+ if (outermode == word_mode && GET_CODE (op) == NOT)
+ {
+ rtx op0 = simplify_subreg (outermode, XEXP (op, 0), innermode, byte);
+ if (op0)
+ return simplify_gen_unary (GET_CODE (op), outermode, op0, outermode);
}
scalar_int_mode int_outermode, int_innermode;
@@ -8689,6 +8704,7 @@ test_scalar_int_ext_ops (machine_mode bmode, machine_mode
smode)
Fixes it. (ignore the prints).
But basically the new code does not hit in this case since there is already:
```
/* Attempt to simplify WORD_MODE SUBREGs of bitwise expressions. */
if (outermode == word_mode
&& (GET_CODE (op) == IOR || GET_CODE (op) == XOR || GET_CODE (op) == AND)
&& SCALAR_INT_MODE_P (innermode))
{
rtx op0 = simplify_subreg (outermode, XEXP (op, 0), innermode, byte);
rtx op1 = simplify_subreg (outermode, XEXP (op, 1), innermode, byte);
if (op0 && op1)
return simplify_gen_binary (GET_CODE (op), outermode, op0, op1);
}
```
But this does not handle `(subreg:word (not:larger (subreg:larger (reg:word) 0)
0)`
So there is a disconnect between what is produced by the above vs what is done
by the new code due to the missing of the (subreg:word (not a) into (not
(subreg a)) .
So I will add that.
