<a...@codesourcery.com> writes:
> This patch was part of the original patch we acquired from Honza and Martin.
>
> It simplifies vector elements that are inactive, according to the mask.
>
> 2018-09-05 Jan Hubicka <j...@suse.cz>
> Martin Jambor <mjam...@suse.cz>
>
> * simplify-rtx.c (simplify_merge_mask): New function.
> (simplify_ternary_operation): Use it, also see if VEC_MERGEs with the
> same masks are used in op1 or op2.
Would be good to have self-tests for the new transforms.
> +/* X is an operand number OP of VEC_MERGE operation with MASK.
"of a". Might also be worth mentioning that X can be a nested
operation of a VEC_MERGE with a different mode, although it always
has the same number of elements as MASK.
> + Try to simplify using knowledge that values outside of MASK
"simplify X"
> + will not be used. */
> +
> +rtx
> +simplify_merge_mask (rtx x, rtx mask, int op)
> +{
> + gcc_assert (VECTOR_MODE_P (GET_MODE (x)));
> + poly_uint64 nunits = GET_MODE_NUNITS (GET_MODE (x));
> + if (GET_CODE (x) == VEC_MERGE && rtx_equal_p (XEXP (x, 2), mask))
> + {
> + if (!side_effects_p (XEXP (x, 1 - op)))
> + return XEXP (x, op);
> + }
> + if (side_effects_p (x))
> + return NULL_RTX;
> + if (UNARY_P (x)
> + && VECTOR_MODE_P (GET_MODE (XEXP (x, 0)))
> + && maybe_eq (GET_MODE_NUNITS (GET_MODE (XEXP (x, 0))), nunits))
known_eq, since we require equality for correctness. Same for the
other tests.
> + {
> + rtx top0 = simplify_merge_mask (XEXP (x, 0), mask, op);
> + if (top0)
> + return simplify_gen_unary (GET_CODE (x), GET_MODE (x), top0,
> + GET_MODE (XEXP (x, 0)));
> + }
> + if (BINARY_P (x)
> + && VECTOR_MODE_P (GET_MODE (XEXP (x, 0)))
> + && maybe_eq (GET_MODE_NUNITS (GET_MODE (XEXP (x, 0))), nunits)
> + && VECTOR_MODE_P (GET_MODE (XEXP (x, 1)))
> + && maybe_eq (GET_MODE_NUNITS (GET_MODE (XEXP (x, 1))), nunits))
> + {
> + rtx top0 = simplify_merge_mask (XEXP (x, 0), mask, op);
> + rtx top1 = simplify_merge_mask (XEXP (x, 1), mask, op);
> + if (top0 || top1)
> + return simplify_gen_binary (GET_CODE (x), GET_MODE (x),
> + top0 ? top0 : XEXP (x, 0),
> + top1 ? top1 : XEXP (x, 1));
> + }
> + if (GET_RTX_CLASS (GET_CODE (x)) == RTX_TERNARY
> + && VECTOR_MODE_P (GET_MODE (XEXP (x, 0)))
> + && maybe_eq (GET_MODE_NUNITS (GET_MODE (XEXP (x, 0))), nunits)
> + && VECTOR_MODE_P (GET_MODE (XEXP (x, 1)))
> + && maybe_eq (GET_MODE_NUNITS (GET_MODE (XEXP (x, 1))), nunits)
> + && VECTOR_MODE_P (GET_MODE (XEXP (x, 2)))
> + && maybe_eq (GET_MODE_NUNITS (GET_MODE (XEXP (x, 2))), nunits))
> + {
> + rtx top0 = simplify_merge_mask (XEXP (x, 0), mask, op);
> + rtx top1 = simplify_merge_mask (XEXP (x, 1), mask, op);
> + rtx top2 = simplify_merge_mask (XEXP (x, 2), mask, op);
> + if (top0 || top1)
> + return simplify_gen_ternary (GET_CODE (x), GET_MODE (x),
> + GET_MODE (XEXP (x, 0)),
> + top0 ? top0 : XEXP (x, 0),
> + top1 ? top1 : XEXP (x, 1),
> + top2 ? top2 : XEXP (x, 2));
> + }
> + return NULL_RTX;
> +}
> +
>
> /* Simplify CODE, an operation with result mode MODE and three operands,
> OP0, OP1, and OP2. OP0_MODE was the mode of OP0 before it became
> @@ -5967,6 +6026,28 @@ simplify_ternary_operation (enum rtx_code code,
> machine_mode mode,
> && !side_effects_p (op2) && !side_effects_p (op1))
> return op0;
>
> + if (!side_effects_p (op2))
> + {
> + rtx top0 = simplify_merge_mask (op0, op2, 0);
> + rtx top1 = simplify_merge_mask (op1, op2, 1);
> + if (top0 || top1)
> + return simplify_gen_ternary (code, mode, mode,
> + top0 ? top0 : op0,
> + top1 ? top1 : op1, op2);
> + }
> +
> + if (GET_CODE (op0) == VEC_MERGE
> + && rtx_equal_p (op2, XEXP (op0, 2))
> + && !side_effects_p (XEXP (op0, 1)) && !side_effects_p (op2))
> + return simplify_gen_ternary (code, mode, mode,
> + XEXP (op0, 0), op1, op2);
> +
> + if (GET_CODE (op1) == VEC_MERGE
> + && rtx_equal_p (op2, XEXP (op1, 2))
> + && !side_effects_p (XEXP (op0, 0)) && !side_effects_p (op2))
> + return simplify_gen_ternary (code, mode, mode,
> + XEXP (op0, 1), op1, op2);
Doesn't simplify_merge_mask make the second two redundant? I couldn't
see the difference between them and the first condition tested by
simplify_merge_mask.
Thanks,
Richard
