https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97249
--- Comment #7 from Hongtao.liu <crazylht at gmail dot com> ---
I'm testing
---
diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c
index 869f0d11b2e..9c397157f28 100644
--- a/gcc/simplify-rtx.c
+++ b/gcc/simplify-rtx.c
@@ -4170,6 +4170,33 @@ simplify_binary_operation_1 (enum rtx_code code,
machine_mode mode,
return subop1;
}
}
+
+ /* For cases like
+ (vec_select:V2SI (subreg:V4SI (inner:V2SI) 0)
+ (parallel [(const_int 0) (const_int 1)])).
+ return inner directly. */
+ if (GET_CODE (trueop0) == SUBREG
+ && paradoxical_subreg_p (trueop0)
+ && mode == GET_MODE (XEXP (trueop0, 0))
+ && (GET_MODE_NUNITS (GET_MODE (trueop0))).is_constant (&l0)
+ && (GET_MODE_NUNITS (mode)).is_constant (&l1)
+ && l0 % l1 == 0)
+ {
+ gcc_assert (known_eq (XVECLEN (trueop1, 0), l1));
+ unsigned HOST_WIDE_INT expect = (HOST_WIDE_INT_1U << l1) - 1;
+ unsigned HOST_WIDE_INT sel = 0;
+ int i = 0;
+ for (;i != l1; i++)
+ {
+ rtx j = XVECEXP (trueop1, 0, i);
+ if (!CONST_INT_P (j))
+ break;
+ sel |= HOST_WIDE_INT_1U << UINTVAL (j);
+ }
+ /* ??? Need to simplify XEXP (trueop0, 0) here. */
+ if (sel == expect)
+ return XEXP (trueop0, 0);
+ }
}
if (XVECLEN (trueop1, 0) == 1
---
