Re: [PATCH] LoongArch: Generate bytepick.[wd] for suitable bit operation pattern

[Lulu Cheng <chenglulu@loongson.cn>]

在 2023/2/4 上午1:50, Xi Ruoyao 写道:
> We can use bytepick.[wd] for
>
>      a << (8 * x) | b >> (8 * (sizeof(a) - x))
>
> while a and b are uint32_t or uint64_t.  This is useful for some cases,
> for example:
> https://sourceware.org/pipermail/libc-alpha/2023-February/145203.html
>
> Bootstrapped and regtested on loongarch64-linux-gnu.
> Ok for trunk (now or GCC 14 stage 1)?

LGTM!

I think this change is not big and can be merged into the trunk branch.


Thanks!


> gcc/ChangeLog:
>
> 	* config/loongarch/loongarch.md (bytepick_w_ashift_amount):
> 	New define_int_iterator.
> 	(bytepick_d_ashift_amount): Likewise.
> 	(bytepick_imm): New define_int_attr.
> 	(bytepick_w_lshiftrt_amount): Likewise.
> 	(bytepick_d_lshiftrt_amount): Likewise.
> 	(bytepick_w_<bytepick_imm>): New define_insn template.
> 	(bytepick_w_<bytepick_imm>_extend): Likewise.
> 	(bytepick_d_<bytepick_imm>): Likewise.
> 	(bytepick_w): Remove unused define_insn.
> 	(bytepick_d): Likewise.
> 	(UNSPEC_BYTEPICK_W): Remove unused unspec.
> 	(UNSPEC_BYTEPICK_D): Likewise.
> 	* config/loongarch/predicates.md (const_0_to_3_operand):
> 	Remove unused define_predicate.
> 	(const_0_to_7_operand): Likewise.
>
> gcc/testsuite/ChangeLog:
>
> 	* g++.target/loongarch/bytepick.C: New test.
> ---
>   gcc/config/loongarch/loongarch.md             | 60 ++++++++++++++-----
>   gcc/config/loongarch/predicates.md            |  8 ---
>   gcc/testsuite/g++.target/loongarch/bytepick.C | 32 ++++++++++
>   3 files changed, 77 insertions(+), 23 deletions(-)
>   create mode 100644 gcc/testsuite/g++.target/loongarch/bytepick.C
>
> diff --git a/gcc/config/loongarch/loongarch.md b/gcc/config/loongarch/loongarch.md
> index 0884ec09dfb..3509c3c21c1 100644
> --- a/gcc/config/loongarch/loongarch.md
> +++ b/gcc/config/loongarch/loongarch.md
> @@ -48,8 +48,6 @@ (define_c_enum "unspec" [
>     UNSPEC_EH_RETURN
>   
>     ;; Bit operation
> -  UNSPEC_BYTEPICK_W
> -  UNSPEC_BYTEPICK_D
>     UNSPEC_BITREV_4B
>     UNSPEC_BITREV_8B
>   
> @@ -544,6 +542,27 @@ (define_int_attr lrint_allow_inexact [(UNSPEC_FTINT "1")
>   				      (UNSPEC_FTINTRM "0")
>   				      (UNSPEC_FTINTRP "0")])
>   
> +;; Iterator and attributes for bytepick.d
> +(define_int_iterator bytepick_w_ashift_amount [8 16 24])
> +(define_int_attr bytepick_w_lshiftrt_amount [(8 "24")
> +					     (16 "16")
> +					     (24 "8")])
> +(define_int_iterator bytepick_d_ashift_amount [8 16 24 32 40 48 56])
> +(define_int_attr bytepick_d_lshiftrt_amount [(8 "56")
> +					     (16 "48")
> +					     (24 "40")
> +					     (32 "32")
> +					     (40 "24")
> +					     (48 "16")
> +					     (56 "8")])
> +(define_int_attr bytepick_imm [(8 "1")
> +				 (16 "2")
> +				 (24 "3")
> +				 (32 "4")
> +				 (40 "5")
> +				 (48 "6")
> +				 (56 "7")])
> +
>   ;;
>   ;;  ....................
>   ;;
> @@ -3364,24 +3383,35 @@ (define_insn "fclass_<fmt>"
>     [(set_attr "type" "unknown")
>      (set_attr "mode" "<MODE>")])
>   
> -(define_insn "bytepick_w"
> +(define_insn "bytepick_w_<bytepick_imm>"
>     [(set (match_operand:SI 0 "register_operand" "=r")
> -	(unspec:SI [(match_operand:SI 1 "register_operand" "r")
> -		    (match_operand:SI 2 "register_operand" "r")
> -		    (match_operand:SI 3 "const_0_to_3_operand" "n")]
> -		    UNSPEC_BYTEPICK_W))]
> +	(ior:SI (lshiftrt (match_operand:SI 1 "register_operand" "r")
> +			  (const_int <bytepick_w_lshiftrt_amount>))
> +		(ashift (match_operand:SI 2 "register_operand" "r")
> +			(const_int bytepick_w_ashift_amount))))]
>     ""
> -  "bytepick.w\t%0,%1,%2,%z3"
> +  "bytepick.w\t%0,%1,%2,<bytepick_imm>"
>     [(set_attr "mode" "SI")])
>   
> -(define_insn "bytepick_d"
> +(define_insn "bytepick_w_<bytepick_imm>_extend"
>     [(set (match_operand:DI 0 "register_operand" "=r")
> -	(unspec:DI [(match_operand:DI 1 "register_operand" "r")
> -		    (match_operand:DI 2 "register_operand" "r")
> -		    (match_operand:DI 3 "const_0_to_7_operand" "n")]
> -		    UNSPEC_BYTEPICK_D))]
> -  ""
> -  "bytepick.d\t%0,%1,%2,%z3"
> +	(sign_extend:DI
> +	  (ior:SI (lshiftrt (match_operand:SI 1 "register_operand" "r")
> +			    (const_int <bytepick_w_lshiftrt_amount>))
> +		  (ashift (match_operand:SI 2 "register_operand" "r")
> +			  (const_int bytepick_w_ashift_amount)))))]
> +  "TARGET_64BIT"
> +  "bytepick.w\t%0,%1,%2,<bytepick_imm>"
> +  [(set_attr "mode" "SI")])
> +
> +(define_insn "bytepick_d_<bytepick_imm>"
> +  [(set (match_operand:DI 0 "register_operand" "=r")
> +	(ior:DI (lshiftrt (match_operand:DI 1 "register_operand" "r")
> +			  (const_int <bytepick_d_lshiftrt_amount>))
> +		(ashift (match_operand:DI 2 "register_operand" "r")
> +			(const_int bytepick_d_ashift_amount))))]
> +  "TARGET_64BIT"
> +  "bytepick.d\t%0,%1,%2,<bytepick_imm>"
>     [(set_attr "mode" "DI")])
>   
>   (define_insn "bitrev_4b"
> diff --git a/gcc/config/loongarch/predicates.md b/gcc/config/loongarch/predicates.md
> index de0a363e2e4..95140280f1e 100644
> --- a/gcc/config/loongarch/predicates.md
> +++ b/gcc/config/loongarch/predicates.md
> @@ -91,14 +91,6 @@ (define_predicate "reg_or_1_operand"
>     (ior (match_operand 0 "const_1_operand")
>          (match_operand 0 "register_operand")))
>   
> -(define_predicate "const_0_to_3_operand"
> -  (and (match_code "const_int")
> -       (match_test "IN_RANGE (INTVAL (op), 0, 3)")))
> -
> -(define_predicate "const_0_to_7_operand"
> -  (and (match_code "const_int")
> -       (match_test "IN_RANGE (INTVAL (op), 0, 7)")))
> -
>   (define_predicate "lu52i_mask_operand"
>     (and (match_code "const_int")
>          (match_test "UINTVAL (op) == 0xfffffffffffff")))
> diff --git a/gcc/testsuite/g++.target/loongarch/bytepick.C b/gcc/testsuite/g++.target/loongarch/bytepick.C
> new file mode 100644
> index 00000000000..a39e2fa65b7
> --- /dev/null
> +++ b/gcc/testsuite/g++.target/loongarch/bytepick.C
> @@ -0,0 +1,32 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -mabi=lp64d" } */
> +/* { dg-final { scan-assembler-times "bytepick.w\t\\\$r4,\\\$r5,\\\$r4" 3 } } */
> +/* { dg-final { scan-assembler-times "bytepick.d\t\\\$r4,\\\$r5,\\\$r4" 7 } } */
> +/* { dg-final { scan-assembler-not "slli.w" } } */
> +
> +template <class T, int offs>
> +T
> +merge (T a, T b)
> +{
> +  return a << offs | b >> (8 * sizeof (T) - offs);
> +}
> +
> +using u32 = __UINT32_TYPE__;
> +using u64 = __UINT64_TYPE__;
> +using i64 = __INT64_TYPE__;
> +
> +template u32 merge<u32, 8> (u32, u32);
> +template u32 merge<u32, 16> (u32, u32);
> +template u32 merge<u32, 24> (u32, u32);
> +
> +template u64 merge<u64, 8> (u64, u64);
> +template u64 merge<u64, 16> (u64, u64);
> +template u64 merge<u64, 24> (u64, u64);
> +template u64 merge<u64, 32> (u64, u64);
> +template u64 merge<u64, 40> (u64, u64);
> +template u64 merge<u64, 48> (u64, u64);
> +template u64 merge<u64, 56> (u64, u64);
> +
> +/* we cannot use bytepick for the following cases */
> +template i64 merge<i64, 8> (i64, i64);
> +template u64 merge<u64, 42> (u64, u64);