From: Richard Biener <richard.guenther@gmail.com>
To: pan2.li@intel.com
Cc: gcc-patches@gcc.gnu.org, juzhe.zhong@rivai.ai,
kito.cheng@gmail.com, jeffreyalaw@gmail.com,
rdapp.gcc@gmail.com
Subject: Re: [PATCH v2] Internal-fn: Support new IFN SAT_TRUNC for unsigned scalar int
Date: Thu, 27 Jun 2024 08:07:30 +0200 [thread overview]
Message-ID: <CAFiYyc1Ywb8JbPn2gCqUaud079m8CKjNvBjuCCCAK1+u8jif+A@mail.gmail.com> (raw)
In-Reply-To: <20240627051216.1817555-1-pan2.li@intel.com>
On Thu, Jun 27, 2024 at 7:12 AM <pan2.li@intel.com> wrote:
>
> From: Pan Li <pan2.li@intel.com>
>
> This patch would like to add the middle-end presentation for the
> saturation truncation. Aka set the result of truncated value to
> the max value when overflow. It will take the pattern similar
> as below.
>
> Form 1:
> #define DEF_SAT_U_TRUC_FMT_1(WT, NT) \
> NT __attribute__((noinline)) \
> sat_u_truc_##T##_fmt_1 (WT x) \
> { \
> bool overflow = x > (WT)(NT)(-1); \
> return ((NT)x) | (NT)-overflow; \
> }
>
> For example, truncated uint16_t to uint8_t, we have
>
> * SAT_TRUNC (254) => 254
> * SAT_TRUNC (255) => 255
> * SAT_TRUNC (256) => 255
> * SAT_TRUNC (65536) => 255
>
> Given below SAT_TRUNC from uint64_t to uint32_t.
>
> DEF_SAT_U_TRUC_FMT_1 (uint64_t, uint32_t)
>
> Before this patch:
> __attribute__((noinline))
> uint32_t sat_u_truc_T_fmt_1 (uint64_t x)
> {
> _Bool overflow;
> unsigned int _1;
> unsigned int _2;
> unsigned int _3;
> uint32_t _6;
>
> ;; basic block 2, loop depth 0
> ;; pred: ENTRY
> overflow_5 = x_4(D) > 4294967295;
> _1 = (unsigned int) x_4(D);
> _2 = (unsigned int) overflow_5;
> _3 = -_2;
> _6 = _1 | _3;
> return _6;
> ;; succ: EXIT
>
> }
>
> After this patch:
> __attribute__((noinline))
> uint32_t sat_u_truc_T_fmt_1 (uint64_t x)
> {
> uint32_t _6;
>
> ;; basic block 2, loop depth 0
> ;; pred: ENTRY
> _6 = .SAT_TRUNC (x_4(D)); [tail call]
> return _6;
> ;; succ: EXIT
>
> }
OK.
Thanks,
Richard.
> The below tests are passed for this patch:
> *. The rv64gcv fully regression tests.
> *. The rv64gcv build with glibc.
> *. The x86 bootstrap tests.
> *. The x86 fully regression tests.
>
> gcc/ChangeLog:
>
> * internal-fn.def (SAT_TRUNC): Add new signed IFN sat_trunc as
> unary_convert.
> * match.pd: Add new matching pattern for unsigned int sat_trunc.
> * optabs.def (OPTAB_CL): Add unsigned and signed optab.
> * tree-ssa-math-opts.cc (gimple_unsigend_integer_sat_trunc): Add
> new decl for the matching pattern generated func.
> (match_unsigned_saturation_trunc): Add new func impl to match
> the .SAT_TRUNC.
> (math_opts_dom_walker::after_dom_children): Add .SAT_TRUNC match
> function under BIT_IOR_EXPR case.
>
> Signed-off-by: Pan Li <pan2.li@intel.com>
> ---
> gcc/internal-fn.def | 2 ++
> gcc/match.pd | 16 ++++++++++++++++
> gcc/optabs.def | 3 +++
> gcc/tree-ssa-math-opts.cc | 32 ++++++++++++++++++++++++++++++++
> 4 files changed, 53 insertions(+)
>
> diff --git a/gcc/internal-fn.def b/gcc/internal-fn.def
> index a8c83437ada..915d329c05a 100644
> --- a/gcc/internal-fn.def
> +++ b/gcc/internal-fn.def
> @@ -278,6 +278,8 @@ DEF_INTERNAL_SIGNED_OPTAB_FN (MULHRS, ECF_CONST | ECF_NOTHROW, first,
> DEF_INTERNAL_SIGNED_OPTAB_FN (SAT_ADD, ECF_CONST, first, ssadd, usadd, binary)
> DEF_INTERNAL_SIGNED_OPTAB_FN (SAT_SUB, ECF_CONST, first, sssub, ussub, binary)
>
> +DEF_INTERNAL_SIGNED_OPTAB_FN (SAT_TRUNC, ECF_CONST, first, sstrunc, ustrunc, unary_convert)
> +
> DEF_INTERNAL_COND_FN (ADD, ECF_CONST, add, binary)
> DEF_INTERNAL_COND_FN (SUB, ECF_CONST, sub, binary)
> DEF_INTERNAL_COND_FN (MUL, ECF_CONST, smul, binary)
> diff --git a/gcc/match.pd b/gcc/match.pd
> index 3d0689c9312..06120a1c62c 100644
> --- a/gcc/match.pd
> +++ b/gcc/match.pd
> @@ -3210,6 +3210,22 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
> (if (INTEGRAL_TYPE_P (type) && TYPE_UNSIGNED (type)
> && types_match (type, @0, @1))))
>
> +/* Unsigned saturation truncate, case 1 (), sizeof (WT) > sizeof (NT).
> + SAT_U_TRUNC = (NT)x | (NT)(-(X > (WT)(NT)(-1))). */
> +(match (unsigned_integer_sat_trunc @0)
> + (bit_ior:c (negate (convert (gt @0 INTEGER_CST@1)))
> + (convert @0))
> + (with {
> + unsigned itype_precision = TYPE_PRECISION (TREE_TYPE (@0));
> + unsigned otype_precision = TYPE_PRECISION (type);
> + wide_int trunc_max = wi::mask (itype_precision / 2, false, itype_precision);
> + wide_int int_cst = wi::to_wide (@1, itype_precision);
> + }
> + (if (INTEGRAL_TYPE_P (type) && TYPE_UNSIGNED (type)
> + && TYPE_UNSIGNED (TREE_TYPE (@0))
> + && otype_precision < itype_precision
> + && wi::eq_p (trunc_max, int_cst)))))
> +
> /* x > y && x != XXX_MIN --> x > y
> x > y && x == XXX_MIN --> false . */
> (for eqne (eq ne)
> diff --git a/gcc/optabs.def b/gcc/optabs.def
> index bc2611abdc2..c16580ce956 100644
> --- a/gcc/optabs.def
> +++ b/gcc/optabs.def
> @@ -63,6 +63,9 @@ OPTAB_CX(fractuns_optab, "fractuns$Q$b$I$a2")
> OPTAB_CL(satfract_optab, "satfract$b$Q$a2", SAT_FRACT, "satfract", gen_satfract_conv_libfunc)
> OPTAB_CL(satfractuns_optab, "satfractuns$I$b$Q$a2", UNSIGNED_SAT_FRACT, "satfractuns", gen_satfractuns_conv_libfunc)
>
> +OPTAB_CL(ustrunc_optab, "ustrunc$b$a2", US_TRUNCATE, "ustrunc", NULL)
> +OPTAB_CL(sstrunc_optab, "sstrunc$b$a2", SS_TRUNCATE, "sstrunc", NULL)
> +
> OPTAB_CD(sfixtrunc_optab, "fix_trunc$F$b$I$a2")
> OPTAB_CD(ufixtrunc_optab, "fixuns_trunc$F$b$I$a2")
>
> diff --git a/gcc/tree-ssa-math-opts.cc b/gcc/tree-ssa-math-opts.cc
> index 57085488722..3783a874699 100644
> --- a/gcc/tree-ssa-math-opts.cc
> +++ b/gcc/tree-ssa-math-opts.cc
> @@ -4088,6 +4088,7 @@ arith_overflow_check_p (gimple *stmt, gimple *cast_stmt, gimple *&use_stmt,
>
> extern bool gimple_unsigned_integer_sat_add (tree, tree*, tree (*)(tree));
> extern bool gimple_unsigned_integer_sat_sub (tree, tree*, tree (*)(tree));
> +extern bool gimple_unsigned_integer_sat_trunc (tree, tree*, tree (*)(tree));
>
> static void
> build_saturation_binary_arith_call (gimple_stmt_iterator *gsi, internal_fn fn,
> @@ -4216,6 +4217,36 @@ match_unsigned_saturation_sub (gimple_stmt_iterator *gsi, gphi *phi)
> ops[0], ops[1]);
> }
>
> +/*
> + * Try to match saturation unsigned sub.
> + * uint16_t x_4(D);
> + * uint8_t _6;
> + * overflow_5 = x_4(D) > 255;
> + * _1 = (unsigned char) x_4(D);
> + * _2 = (unsigned char) overflow_5;
> + * _3 = -_2;
> + * _6 = _1 | _3;
> + * =>
> + * _6 = .SAT_TRUNC (x_4(D));
> + * */
> +static void
> +match_unsigned_saturation_trunc (gimple_stmt_iterator *gsi, gassign *stmt)
> +{
> + tree ops[1];
> + tree lhs = gimple_assign_lhs (stmt);
> + tree type = TREE_TYPE (lhs);
> +
> + if (gimple_unsigned_integer_sat_trunc (lhs, ops, NULL)
> + && direct_internal_fn_supported_p (IFN_SAT_TRUNC,
> + tree_pair (type, TREE_TYPE (ops[0])),
> + OPTIMIZE_FOR_BOTH))
> + {
> + gcall *call = gimple_build_call_internal (IFN_SAT_TRUNC, 1, ops[0]);
> + gimple_call_set_lhs (call, lhs);
> + gsi_replace (gsi, call, /* update_eh_info */ true);
> + }
> +}
> +
> /* Recognize for unsigned x
> x = y - z;
> if (x > y)
> @@ -6188,6 +6219,7 @@ math_opts_dom_walker::after_dom_children (basic_block bb)
>
> case BIT_IOR_EXPR:
> match_unsigned_saturation_add (&gsi, as_a<gassign *> (stmt));
> + match_unsigned_saturation_trunc (&gsi, as_a<gassign *> (stmt));
> /* fall-through */
> case BIT_XOR_EXPR:
> match_uaddc_usubc (&gsi, stmt, code);
> --
> 2.34.1
>
next prev parent reply other threads:[~2024-06-27 6:07 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-06-26 1:45 [PATCH v1] " pan2.li
2024-06-26 13:51 ` Richard Biener
2024-06-26 14:18 ` Li, Pan2
2024-06-27 5:12 ` [PATCH v2] " pan2.li
2024-06-27 6:07 ` Richard Biener [this message]
2024-06-27 6:14 ` Li, Pan2
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