https://gcc.gnu.org/g:0340177d54d08b6375391ba164a878e6a596275e
commit r16-2649-g0340177d54d08b6375391ba164a878e6a596275e
Author: Andrew Pinski <quic_apin...@quicinc.com>
Date: Tue Jul 29 21:49:16 2025 -0700
simplify-rtx: Add `(subreg (not a))` simplification for word_mode [PR121308]
Right now in simplify_subreg, there is code to try to simplify for word_mode
with the binary bitwise operators. The unary bitwise operator is not handle,
this causes an odd mix match and the new self testing code that was added
with
r16-2614-g965564eafb721f was not expecting.
The self testing code was for testing the newly added code but since there
was already code that handles word_mode, we hit the mismatch but only
for targets where word_mode is SImode (or smaller).
This adds the code to handle `not` in a similar fashion as the other
bitwise operators for word_mode.
Changes since v1:
* v2: add `&& SCALAR_INT_MODE_P (innermode)` to the conditional.
Bootstrapped and tested on x86_64-linux-gnu.
PR rtl-optimization/121308
gcc/ChangeLog:
* simplify-rtx.cc (simplify_context::simplify_subreg): Handle
subreg of `not` with word_mode to make it symmetric with the
other bitwise operators.
Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com>
Diff:
---
gcc/simplify-rtx.cc | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/gcc/simplify-rtx.cc b/gcc/simplify-rtx.cc
index 442da9f40fae..c723a07f06bb 100644
--- a/gcc/simplify-rtx.cc
+++ b/gcc/simplify-rtx.cc
@@ -8344,6 +8344,15 @@ simplify_context::simplify_subreg (machine_mode
outermode, rtx op,
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
+ && SCALAR_INT_MODE_P (innermode))
+ {
+ 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;
if (is_a <scalar_int_mode> (outermode, &int_outermode)
&& is_a <scalar_int_mode> (innermode, &int_innermode)
