From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 1880) id 4B6AD38582A1; Sat, 16 Jul 2022 07:28:18 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 4B6AD38582A1 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="utf-8" From: Max Filippov To: gcc-cvs@gcc.gnu.org Subject: [gcc r13-1719] xtensa: constantsynth: Make try to find shorter instruction X-Act-Checkin: gcc X-Git-Author: Takayuki 'January June' Suwa X-Git-Refname: refs/heads/master X-Git-Oldrev: bdc7b765f8728cbb769fe1eeef773eda15578aee X-Git-Newrev: 1884f8978237b15013576a720bcb32e7c5647574 Message-Id: <20220716072818.4B6AD38582A1@sourceware.org> Date: Sat, 16 Jul 2022 07:28:18 +0000 (GMT) X-BeenThere: gcc-cvs@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-cvs mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 16 Jul 2022 07:28:18 -0000 https://gcc.gnu.org/g:1884f8978237b15013576a720bcb32e7c5647574 commit r13-1719-g1884f8978237b15013576a720bcb32e7c5647574 Author: Takayuki 'January June' Suwa Date: Fri Jul 15 19:50:52 2022 +0900 xtensa: constantsynth: Make try to find shorter instruction This patch allows the constant synthesis to choose shorter instruction if possible. /* example */ int test(void) { return 128 << 8; } ;; before test: movi a2, 0x100 addmi a2, a2, 0x7f00 ret.n ;; after test: movi.n a2, 1 slli a2, a2, 15 ret.n When the Code Density Option is configured, the latter is one byte smaller than the former. gcc/ChangeLog: * config/xtensa/xtensa.cc (xtensa_emit_constantsynth): Remove. (xtensa_constantsynth_2insn): Change to try all three synthetic methods and to use the one that fits the immediate value of the seed into a Narrow Move Immediate instruction "MOVI.N" when the Code Density Option is configured. Diff: --- gcc/config/xtensa/xtensa.cc | 58 ++++++++++++++++++++++----------------------- 1 file changed, 29 insertions(+), 29 deletions(-) diff --git a/gcc/config/xtensa/xtensa.cc b/gcc/config/xtensa/xtensa.cc index 13f2b2b832c..94337452ba8 100644 --- a/gcc/config/xtensa/xtensa.cc +++ b/gcc/config/xtensa/xtensa.cc @@ -1035,35 +1035,35 @@ xtensa_split_operand_pair (rtx operands[4], machine_mode mode) load-immediate / arithmetic ones, instead of a L32R instruction (plus a constant in litpool). */ -static void -xtensa_emit_constantsynth (rtx dst, enum rtx_code code, - HOST_WIDE_INT imm0, HOST_WIDE_INT imm1, - rtx (*gen_op)(rtx, HOST_WIDE_INT), - HOST_WIDE_INT imm2) -{ - gcc_assert (REG_P (dst)); - emit_move_insn (dst, GEN_INT (imm0)); - emit_move_insn (dst, gen_rtx_fmt_ee (code, SImode, - dst, GEN_INT (imm1))); - if (gen_op) - emit_move_insn (dst, gen_op (dst, imm2)); -} - static int xtensa_constantsynth_2insn (rtx dst, HOST_WIDE_INT srcval, rtx (*gen_op)(rtx, HOST_WIDE_INT), HOST_WIDE_INT op_imm) { - int shift = exact_log2 (srcval + 1); + HOST_WIDE_INT imm = INT_MAX; + rtx x = NULL_RTX; + int shift; + gcc_assert (REG_P (dst)); + + shift = exact_log2 (srcval + 1); if (IN_RANGE (shift, 1, 31)) { - xtensa_emit_constantsynth (dst, LSHIFTRT, -1, 32 - shift, - gen_op, op_imm); - return 1; + imm = -1; + x = gen_lshrsi3 (dst, dst, GEN_INT (32 - shift)); } - if (IN_RANGE (srcval, (-2048 - 32768), (2047 + 32512))) + + shift = ctz_hwi (srcval); + if ((!x || (TARGET_DENSITY && ! IN_RANGE (imm, -32, 95))) + && xtensa_simm12b (srcval >> shift)) + { + imm = srcval >> shift; + x = gen_ashlsi3 (dst, dst, GEN_INT (shift)); + } + + if ((!x || (TARGET_DENSITY && ! IN_RANGE (imm, -32, 95))) + && IN_RANGE (srcval, (-2048 - 32768), (2047 + 32512))) { HOST_WIDE_INT imm0, imm1; @@ -1076,19 +1076,19 @@ xtensa_constantsynth_2insn (rtx dst, HOST_WIDE_INT srcval, imm0 = srcval - imm1; if (TARGET_DENSITY && imm1 < 32512 && IN_RANGE (imm0, 224, 255)) imm0 -= 256, imm1 += 256; - xtensa_emit_constantsynth (dst, PLUS, imm0, imm1, gen_op, op_imm); - return 1; + imm = imm0; + x = gen_addsi3 (dst, dst, GEN_INT (imm1)); } - shift = ctz_hwi (srcval); - if (xtensa_simm12b (srcval >> shift)) - { - xtensa_emit_constantsynth (dst, ASHIFT, srcval >> shift, shift, - gen_op, op_imm); - return 1; - } + if (!x) + return 0; - return 0; + emit_move_insn (dst, GEN_INT (imm)); + emit_insn (x); + if (gen_op) + emit_move_insn (dst, gen_op (dst, op_imm)); + + return 1; } static rtx