When mask is (1 << (prec - imm) - 1) which is used to clear upper bits
of A, then it can be simplified to LSHIFTRT.
i.e Simplify
(and:v8hi
(ashifrt:v8hi A 8)
(const_vector 0xff x8))
to
(lshifrt:v8hi A 8)
Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,}.
Ok of trunk?
gcc/ChangeLog:
PR target/114428
* simplify-rtx.cc
(simplify_context::simplify_binary_operation_1):
Simplify (AND (ASHIFTRT A imm) mask) to (LSHIFTRT A imm) for
specific mask.
---
gcc/simplify-rtx.cc | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
diff --git a/gcc/simplify-rtx.cc b/gcc/simplify-rtx.cc
index 53f54d1d392..6c91409200e 100644
--- a/gcc/simplify-rtx.cc
+++ b/gcc/simplify-rtx.cc
@@ -4021,6 +4021,31 @@ simplify_context::simplify_binary_operation_1 (rtx_code
code,
return tem;
}
+ /* (and:v4si
+ (ashiftrt:v4si A 16)
+ (const_vector: 0xffff x4))
+ is just (lshiftrt:v4si A 16). */
+ if (VECTOR_MODE_P (mode) && GET_CODE (op0) == ASHIFTRT
+ && (CONST_INT_P (XEXP (op0, 1))
+ || (GET_CODE (XEXP (op0, 1)) == CONST_VECTOR
+ && CONST_VECTOR_DUPLICATE_P (XEXP (op0, 1))))
+ && GET_CODE (op1) == CONST_VECTOR
+ && CONST_VECTOR_DUPLICATE_P (op1))
+ {
+ unsigned HOST_WIDE_INT shift_count
+ = (CONST_INT_P (XEXP (op0, 1))
+ ? UINTVAL (XEXP (op0, 1))
+ : UINTVAL (XVECEXP (XEXP (op0, 1), 0, 0)));
+ unsigned HOST_WIDE_INT inner_prec
+ = GET_MODE_PRECISION (GET_MODE_INNER (mode));
+
+ /* Avoid UD shift count. */
+ if (shift_count < inner_prec
+ && (UINTVAL (XVECEXP (op1, 0, 0))
+ == (HOST_WIDE_INT_1U << (inner_prec - shift_count)) - 1))
+ return simplify_gen_binary (LSHIFTRT, mode, XEXP (op0, 0), XEXP
(op0, 1));
+ }
+
tem = simplify_byte_swapping_operation (code, mode, op0, op1);
if (tem)
return tem;
--
2.31.1
