From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 1923) id 535553858438; Thu, 1 Dec 2022 13:23:51 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 535553858438 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1669901031; bh=I9ISHxollEkRW1Nmc40eCMMvereI8fomYhPlESb71n0=; h=From:To:Subject:Date:From; b=G9i45+Z4VYDY5CrEpv0zvo5i1905iOvwK/8L1Kwr0quVL/K26AekpMRaEERIRjW3j Px2DByoRWuYdW0e3b2WnfMwyESO/60SSQH8i5sN7MWaSE1Z5EMr6Hu8y9dTg3UldTP +gSPDCAvTry9cKgQc4SpAHCED0OTHb3/kfYapmWs= Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit From: Philipp Tomsich To: gcc-cvs@gcc.gnu.org Subject: [gcc(refs/vendors/vrull/heads/for-upstream)] ifcvt: add if-conversion to conditional-zero instructions X-Act-Checkin: gcc X-Git-Author: Philipp Tomsich X-Git-Refname: refs/vendors/vrull/heads/for-upstream X-Git-Oldrev: bfb9bc38ee9431851fa61197f9d3d281fbf58c4d X-Git-Newrev: 02055c4e91c2a858b31d2684fd78e3e0d25f1736 Message-Id: <20221201132351.535553858438@sourceware.org> Date: Thu, 1 Dec 2022 13:23:51 +0000 (GMT) List-Id: https://gcc.gnu.org/g:02055c4e91c2a858b31d2684fd78e3e0d25f1736 commit 02055c4e91c2a858b31d2684fd78e3e0d25f1736 Author: Philipp Tomsich Date: Wed Mar 16 11:23:44 2022 +0100 ifcvt: add if-conversion to conditional-zero instructions Some architectures, as it the case on RISC-V with the proposed ZiCondOps and the vendor-defined XVentanaCondOps, define a conditional-zero instruction that is equivalent to: - the positive form: rd = (rc != 0) ? rs : 0 - the negated form: rd = (rc == 0) ? rs : 0 While noce_try_store_flag_mask will somewhat work for this case, it will generate a number of atomic RTX that will misdirect the cost calculation and may be too long (i.e., 4 RTX and more) to successfully merge at combine-time. Instead, we add two new transforms that attempt to build up what we define as the canonical form of a conditional-zero expression: (set (match_operand 0 "register_operand" "=r") (and (neg (eq_or_ne (match_operand 1 "register_operand" "r") (const_int 0))) (match_operand 2 "register_operand" "r"))) Architectures that provide a conditional-zero are thus expected to define an instruction matching this pattern in their backend. Based on this, we support the following cases: - noce_try_condzero: a ? a : b a ? b : 0 (and then/else swapped) !a ? b : 0 (and then/else swapped) - noce_try_condzero_arith: conditional-plus, conditional-minus, conditional-and, conditional-or, conditional-xor, conditional-shift, conditional-and Given that this is hooked into the CE passes, it is less powerful than a tree-pass (e.g., it can not transform cases where an extension, such as for uint16_t operations is in either the then or else-branch together with the arithmetic) but already covers a good array of cases and triggers across SPEC CPU 2017. Adding transofmrations in a tree pass will be considered as a future improvement. gcc/ChangeLog: * ifcvt.cc (noce_emit_insn): Add prototype. (noce_emit_condzero): Helper for noce_try_condzero and noce_try_condzero_arith transforms. (noce_try_condzero): New transform. (noce_try_condzero_arith): New transform for conditional arithmetic that can be built up by exploiting that the conditional-zero instruction will inject 0, which acts as the neutral element for operations. (noce_process_if_block): Call noce_try_condzero and noce_try_condzero_arith. gcc/testsuite/ChangeLog: * gcc.target/riscv/xventanacondops-and-01.c: New test. * gcc.target/riscv/xventanacondops-and-02.c: New test. * gcc.target/riscv/xventanacondops-eq-01.c: New test. * gcc.target/riscv/xventanacondops-eq-02.c: New test. * gcc.target/riscv/xventanacondops-lt-01.c: New test. * gcc.target/riscv/xventanacondops-ne-01.c: New test. * gcc.target/riscv/xventanacondops-xor-01.c: New test. Commit-changes: 2 - Ran whitespace-cleanup on xventanacondops-ne-01.c. Commit-changes: 4 - Don't modify if_info in noce_try_condzero() to avoid interfering with downstream if-conversion functions, in case that try_condzero fails. (fixes gcc#277). Diff: --- gcc/config/riscv/riscv.cc | 18 ++ gcc/ifcvt.cc | 216 +++++++++++++++++++++ .../gcc.target/riscv/xventanacondops-and-01.c | 16 ++ .../gcc.target/riscv/xventanacondops-and-02.c | 15 ++ .../gcc.target/riscv/xventanacondops-eq-01.c | 11 ++ .../gcc.target/riscv/xventanacondops-eq-02.c | 14 ++ .../gcc.target/riscv/xventanacondops-lt-01.c | 16 ++ .../gcc.target/riscv/xventanacondops-ne-01.c | 10 + .../gcc.target/riscv/xventanacondops-xor-01.c | 14 ++ 9 files changed, 330 insertions(+) diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc index 69e86a59f60..2c4b47dca0e 100644 --- a/gcc/config/riscv/riscv.cc +++ b/gcc/config/riscv/riscv.cc @@ -233,6 +233,7 @@ enum riscv_fusion_pairs RISCV_FUSE_AUIPC_ADDI = (1 << 5), RISCV_FUSE_LUI_LD = (1 << 6), RISCV_FUSE_AUIPC_LD = (1 << 7), + RISCV_FUSE_LDPREINCREMENT = (1 << 8), }; /* Costs of various operations on the different architectures. */ @@ -5930,6 +5931,23 @@ riscv_macro_fusion_pair_p (rtx_insn *prev, rtx_insn *curr) return true; } + if (simple_sets_p && riscv_fusion_enabled_p (RISCV_FUSE_LDPREINCREMENT)) + { + /* We are trying to match the following: + prev (add) == (set (reg:DI rS) + (plus:DI (reg:DI rS) (const_int)) + curr (ld) == (set (reg:DI rD) + (mem:DI (reg:DI rS))) */ + + if (MEM_P (SET_SRC (curr_set)) + && REG_P (XEXP (SET_SRC (curr_set), 0)) + && REGNO (XEXP (SET_SRC (curr_set), 0)) == REGNO (SET_DEST (prev_set)) + && GET_CODE (SET_SRC (prev_set)) == PLUS + && REG_P (XEXP (SET_SRC (prev_set), 0)) + && CONST_INT_P (XEXP (SET_SRC (prev_set), 1))) + return true; + } + if (simple_sets_p && riscv_fusion_enabled_p (RISCV_FUSE_LUI_ADDI)) { /* We are trying to match the following: diff --git a/gcc/ifcvt.cc b/gcc/ifcvt.cc index eb8efb89a89..38d95091520 100644 --- a/gcc/ifcvt.cc +++ b/gcc/ifcvt.cc @@ -97,6 +97,7 @@ static int find_if_case_2 (basic_block, edge, edge); static int dead_or_predicable (basic_block, basic_block, basic_block, edge, int); static void noce_emit_move_insn (rtx, rtx); +static rtx_insn *noce_emit_insn (rtx); static rtx_insn *block_has_only_trap (basic_block); static void need_cmov_or_rewire (basic_block, hash_set *, hash_map *); @@ -787,6 +788,9 @@ static rtx noce_get_alt_condition (struct noce_if_info *, rtx, rtx_insn **); static int noce_try_minmax (struct noce_if_info *); static int noce_try_abs (struct noce_if_info *); static int noce_try_sign_mask (struct noce_if_info *); +static rtx noce_emit_condzero (struct noce_if_info *, rtx, bool = false); +static int noce_try_condzero (struct noce_if_info *); +static int noce_try_condzero_arith (struct noce_if_info *); /* Return the comparison code for reversed condition for IF_INFO, or UNKNOWN if reversing the condition is not possible. */ @@ -1664,6 +1668,214 @@ noce_try_addcc (struct noce_if_info *if_info) return FALSE; } +/* Helper to noce_try_condzero: cond ? a : 0. */ +static rtx +noce_emit_condzero (struct noce_if_info *if_info, rtx a, bool reverse) +{ + /* The canonical form for a conditional-zero-or-value is: + (set (match_operand 0 "register_operand" "=r") + (and (neg (eq_or_ne (match_operand 1 "register_operand" "r") + (const_int 0))) + (match_operand 2 "register_operand" "r"))) + */ + + machine_mode opmode = GET_MODE (if_info->x); + enum rtx_code code = GET_CODE (if_info->cond); + rtx cond; + rtx op_a = XEXP (if_info->cond, 0); + rtx op_b = XEXP (if_info->cond, 1); + + /* If it is not a EQ/NE comparison against const0_rtx, canonicalize + by first synthesizing a truth-value and then building a NE + condition around it. */ + if ((code != EQ && code != NE) || XEXP (if_info->cond, 1) != const0_rtx) + { + rtx tmp = gen_reg_rtx (opmode); + + start_sequence (); + cond = gen_rtx_fmt_ee (code, opmode, op_a, op_b); + if (!noce_emit_insn (gen_rtx_SET (tmp, cond))) + { + end_sequence (); + + /* If we can't emit this pattern, try to reverse it and + invert the polarity of the second test. */ + start_sequence (); + cond = gen_rtx_fmt_ee (reverse_condition (code), opmode, op_a, op_b); + if (!noce_emit_insn (gen_rtx_SET (tmp, cond))) { + end_sequence (); + return NULL_RTX; + } + + /* We have recovered by reversing the first comparison, + so we need change the second one around as well... */ + reverse = !reverse; + } + rtx_insn *seq = get_insns (); + end_sequence (); + emit_insn (seq); + + /* Set up the second comparison that will be embedded in the + canonical conditional-zero-or-value RTX. */ + code = NE; + op_a = tmp; + op_b = const0_rtx; + } + + cond = gen_rtx_fmt_ee (reverse ? reverse_condition (code) : code, + opmode, op_a, op_b); + + /* Build (and (neg (eq_or_ne ... const0_rtx)) (reg )) */ + rtx target = gen_reg_rtx (opmode); + rtx czero = gen_rtx_AND (opmode, gen_rtx_NEG (opmode, cond), a); + noce_emit_move_insn (target, czero); + + return target; +} + +/* Use a conditional-zero instruction for "if (test) x = 0;", if available. */ +static int +noce_try_condzero (struct noce_if_info *if_info) +{ + rtx target; + rtx_insn *seq; + int reversep = 0; + /* Keep local copies of the constituent elements of if_info, as we + may be changing them. We are not allowed to modify if_info + though, as we may fail in this function and can't leave different + semantics behind for the next functions. */ + rtx a = if_info->a; + rtx b = if_info->b; + rtx x = if_info->x; + rtx cond = if_info->cond; + enum rtx_code code = GET_CODE (cond); + rtx cond_arg0 = XEXP (cond, 0); + rtx cond_arg1 = XEXP (cond, 1); + rtx orig_b = NULL_RTX; + + if (!noce_simple_bbs (if_info)) + return FALSE; + + /* We may encounter the form "(b != 0) ? b : a", which can be + simplified to "b | ((b != 0) ? 0 : a)". */ + if (code == NE && cond_arg1 == const0_rtx && + REG_P (b) && rtx_equal_p (b, cond_arg0)) + { + orig_b = b; + b = const0_rtx; + } + + /* We may encounter the form "(b == 0) ? b : a", which can be + simplied to "(b == 0) ? 0 : a". */ + if (code == EQ && cond_arg1 == const0_rtx && + REG_P (b) && rtx_equal_p (b, cond_arg0)) + { + b = const0_rtx; + } + + start_sequence (); + + if ((a == const0_rtx && (REG_P (b) || rtx_equal_p (b, x))) + || ((reversep = (noce_reversed_cond_code (if_info) != UNKNOWN)) + && b == const0_rtx && (REG_P (a) || rtx_equal_p (a, x)))) + { + target = noce_emit_condzero(if_info, reversep ? a : b, reversep); + + /* Handle the case where we replace b in "(b != 0) ? b : a" with + with const0_rtx to then emit "b | ((b != 0) ? 0 : a)". */ + if (orig_b && target) + target = expand_simple_binop (GET_MODE (x), IOR, orig_b, + target, x, 0, OPTAB_WIDEN); + + if (target) + { + if (target != if_info->x) + noce_emit_move_insn (if_info->x, target); + + seq = end_ifcvt_sequence (if_info); + if (!seq || !targetm.noce_conversion_profitable_p (seq, if_info)) + return FALSE; + + emit_insn_before_setloc (seq, if_info->jump, + INSN_LOCATION (if_info->insn_a)); + if_info->transform_name = "noce_try_condzero"; + + return TRUE; + } + } + + end_sequence (); + + return FALSE; +} + +/* Convert "if (test) x op= a;" to a branchless sequence using the + canonical form for a conditional-zero. */ +static int +noce_try_condzero_arith (struct noce_if_info *if_info) +{ + rtx target; + rtx_insn *seq; + rtx_code op = GET_CODE (if_info->a); + const rtx arg0 = XEXP (if_info->a, 0); + const rtx arg1 = XEXP (if_info->a, 1); + + if (!noce_simple_bbs (if_info)) + return FALSE; + + /* Check for no else condition. */ + if (!rtx_equal_p (if_info->x, if_info->b)) + return FALSE; + + if (op != PLUS && op != MINUS && op != IOR && op != XOR && + op != ASHIFT && op != ASHIFTRT && op != LSHIFTRT && op != AND) + return FALSE; + + if (!rtx_equal_p (if_info->x, arg0)) + return FALSE; + + start_sequence (); + + target = noce_emit_condzero(if_info, arg1, op != AND ? true : false); + + if (target) + { + rtx op1 = if_info->x; + + if (op == AND) + { + /* Emit "tmp = x & val;" followed by "tmp |= !cond ? x : 0;" */ + op1 = expand_simple_binop (GET_MODE (if_info->x), AND, op1, + arg1, NULL_RTX, 0, OPTAB_WIDEN); + op = IOR; + } + + if (op1) + target = expand_simple_binop (GET_MODE (if_info->x), op, op1, + target, if_info->x, 0, OPTAB_WIDEN); + } + + if (target) + { + if (target != if_info->x) + noce_emit_move_insn (if_info->x, target); + + seq = end_ifcvt_sequence (if_info); + if (!seq || !targetm.noce_conversion_profitable_p (seq, if_info)) + return FALSE; + + emit_insn_before_setloc(seq, if_info->jump, + INSN_LOCATION(if_info->insn_a)); + if_info->transform_name = "noce_try_condzero_arith"; + + return TRUE; + } + + end_sequence (); + + return FALSE; +} + /* Convert "if (test) x = 0;" to "x &= -(test == 0);" */ static int @@ -3967,8 +4179,12 @@ noce_process_if_block (struct noce_if_info *if_info) { if (noce_try_addcc (if_info)) goto success; + if (noce_try_condzero (if_info)) + goto success; if (noce_try_store_flag_mask (if_info)) goto success; + if (noce_try_condzero_arith (if_info)) + goto success; if (HAVE_conditional_move && noce_try_cmove_arith (if_info)) goto success; diff --git a/gcc/testsuite/gcc.target/riscv/xventanacondops-and-01.c b/gcc/testsuite/gcc.target/riscv/xventanacondops-and-01.c new file mode 100644 index 00000000000..9b26cdf0513 --- /dev/null +++ b/gcc/testsuite/gcc.target/riscv/xventanacondops-and-01.c @@ -0,0 +1,16 @@ +/* { dg-do compile } */ +/* { dg-options "-march=rv64gc_xventanacondops -mabi=lp64" } */ +/* { dg-skip-if "" { *-*-* } { "-O0" "-Og" "-Os" "-Oz" } } */ + +long and1(long a, long b, long c, long d) +{ + if (c < d) + a &= b; + + return a; +} + +/* { dg-final { scan-assembler-times "and\t" 1 } } */ +/* { dg-final { scan-assembler-times "slt" 1 } } */ +/* { dg-final { scan-assembler-times "vt.maskcn" 1 } } */ +/* { dg-final { scan-assembler-times "or\t" 1 } } */ diff --git a/gcc/testsuite/gcc.target/riscv/xventanacondops-and-02.c b/gcc/testsuite/gcc.target/riscv/xventanacondops-and-02.c new file mode 100644 index 00000000000..66d2ec10211 --- /dev/null +++ b/gcc/testsuite/gcc.target/riscv/xventanacondops-and-02.c @@ -0,0 +1,15 @@ +/* { dg-do compile } */ +/* { dg-options "-march=rv64gc_xventanacondops -mabi=lp64" } */ +/* { dg-skip-if "" { *-*-* } { "-O0" "-Og" "-Os" "-Oz" } } */ + +int and2(int a, int b, long c) +{ + if (c) + a &= b; + + return a; +} + +/* { dg-final { scan-assembler-times "and\t" 1 } } */ +/* { dg-final { scan-assembler-times "vt.maskcn" 1 } } */ +/* { dg-final { scan-assembler-times "or\t" 1 } } */ diff --git a/gcc/testsuite/gcc.target/riscv/xventanacondops-eq-01.c b/gcc/testsuite/gcc.target/riscv/xventanacondops-eq-01.c new file mode 100644 index 00000000000..bc877d9e81b --- /dev/null +++ b/gcc/testsuite/gcc.target/riscv/xventanacondops-eq-01.c @@ -0,0 +1,11 @@ +/* { dg-do compile } */ +/* { dg-options "-march=rv64gc_xventanacondops -mabi=lp64" } */ +/* { dg-skip-if "" { *-*-* } { "-O0" "-Og" } } */ + +long +eq1 (long a, long b) +{ + return (a == 0) ? b : 0; +} + +/* { dg-final { scan-assembler-times "vt.maskcn" 1 } } */ diff --git a/gcc/testsuite/gcc.target/riscv/xventanacondops-eq-02.c b/gcc/testsuite/gcc.target/riscv/xventanacondops-eq-02.c new file mode 100644 index 00000000000..28317613ba8 --- /dev/null +++ b/gcc/testsuite/gcc.target/riscv/xventanacondops-eq-02.c @@ -0,0 +1,14 @@ +/* { dg-do compile } */ +/* { dg-options "-march=rv64gc_xventanacondops -mabi=lp64" } */ +/* { dg-skip-if "" { *-*-* } { "-O0" "-Og" } } */ + +long +eq2 (long a, long b) +{ + if (a == 0) + return b; + + return 0; +} + +/* { dg-final { scan-assembler-times "vt.maskcn" 1 } } */ diff --git a/gcc/testsuite/gcc.target/riscv/xventanacondops-lt-01.c b/gcc/testsuite/gcc.target/riscv/xventanacondops-lt-01.c new file mode 100644 index 00000000000..18762ee2bd0 --- /dev/null +++ b/gcc/testsuite/gcc.target/riscv/xventanacondops-lt-01.c @@ -0,0 +1,16 @@ +/* { dg-do compile } */ +/* { dg-options "-march=rv64gc_xventanacondops -mabi=lp64" } */ +/* { dg-skip-if "" { *-*-* } { "-O0" "-Og" "-Os" "-Oz" } } */ + +long long sink (long long); + +long long lt3 (long long a, long long b) +{ + if (a < b) + b = 0; + + return sink(b); +} + +/* { dg-final { scan-assembler-times "vt.maskcn\t" 1 } } */ +/* { dg-final { scan-assembler-times "slt\t" 1 } } */ diff --git a/gcc/testsuite/gcc.target/riscv/xventanacondops-ne-01.c b/gcc/testsuite/gcc.target/riscv/xventanacondops-ne-01.c new file mode 100644 index 00000000000..be8375ba5cf --- /dev/null +++ b/gcc/testsuite/gcc.target/riscv/xventanacondops-ne-01.c @@ -0,0 +1,10 @@ +/* { dg-do compile } */ +/* { dg-options "-march=rv64gc_xventanacondops -mabi=lp64" } */ +/* { dg-skip-if "" { *-*-* } { "-O0" "-Og" } } */ + +long long ne1(long long a, long long b) +{ + return (a != 0) ? b : 0; +} + +/* { dg-final { scan-assembler-times "vt.maskc" 1 } } */ diff --git a/gcc/testsuite/gcc.target/riscv/xventanacondops-xor-01.c b/gcc/testsuite/gcc.target/riscv/xventanacondops-xor-01.c new file mode 100644 index 00000000000..43020790a22 --- /dev/null +++ b/gcc/testsuite/gcc.target/riscv/xventanacondops-xor-01.c @@ -0,0 +1,14 @@ +/* { dg-do compile } */ +/* { dg-options "-march=rv64gc_xventanacondops -mabi=lp64" } */ +/* { dg-skip-if "" { *-*-* } { "-O0" "-Og" "-Os" "-Oz" } } */ + +long xor1(long crc, long poly) +{ + if (crc & 1) + crc ^= poly; + + return crc; +} + +/* { dg-final { scan-assembler-times "vt.maskc" 1 } } */ +/* { dg-final { scan-assembler-times "xor\t" 1 } } */