From patchwork Fri May 20 12:39:29 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kirill Batuzov X-Patchwork-Id: 96592 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [140.186.70.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id B1100B719D for ; Fri, 20 May 2011 22:41:46 +1000 (EST) Received: from localhost ([::1]:54536 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QNP1U-0000nq-4R for incoming@patchwork.ozlabs.org; Fri, 20 May 2011 08:41:44 -0400 Received: from eggs.gnu.org ([140.186.70.92]:44835) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QNOzr-0006ry-2v for qemu-devel@nongnu.org; Fri, 20 May 2011 08:40:04 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QNOzq-0003bZ-2c for qemu-devel@nongnu.org; Fri, 20 May 2011 08:40:03 -0400 Received: from smtp.ispras.ru ([83.149.198.202]:55459) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QNOzp-0003Y3-LB for qemu-devel@nongnu.org; Fri, 20 May 2011 08:40:01 -0400 Received: from bulbul.intra.ispras.ru (winnie.ispras.ru [83.149.198.236]) by smtp.ispras.ru (Postfix) with ESMTP id E4EF35D4116; Fri, 20 May 2011 16:36:08 +0400 (MSD) From: Kirill Batuzov To: qemu-devel@nongnu.org Date: Fri, 20 May 2011 16:39:29 +0400 Message-Id: <4763ae5461ae14adbb6aca5c925fa0fe81f4f214.1305889001.git.batuzovk@ispras.ru> X-Mailer: git-send-email 1.7.4.1 In-Reply-To: References: In-Reply-To: References: X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6, seldom 2.4 (older, 4) X-Received-From: 83.149.198.202 Cc: mj.mccormack@samsung.com, zhur@ispras.ru Subject: [Qemu-devel] [PATCH 2/6] Add copy and constant propagation. X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Make tcg_constant_folding do copy and constant propagation. It is a preparational work before actual constant folding. Signed-off-by: Kirill Batuzov --- tcg/optimize.c | 123 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 123 insertions(+), 0 deletions(-) diff --git a/tcg/optimize.c b/tcg/optimize.c index cf31d18..a761c51 100644 --- a/tcg/optimize.c +++ b/tcg/optimize.c @@ -31,22 +31,139 @@ #include "qemu-common.h" #include "tcg-op.h" +typedef enum { + TCG_TEMP_UNDEF = 0, + TCG_TEMP_CONST, + TCG_TEMP_COPY, + TCG_TEMP_ANY +} tcg_temp_state; + +static int mov_to_movi(int op) +{ + switch (op) { + case INDEX_op_mov_i32: return INDEX_op_movi_i32; +#if TCG_TARGET_REG_BITS == 64 + case INDEX_op_mov_i64: return INDEX_op_movi_i64; +#endif + default: + fprintf(stderr, "Unrecognized operation %d in mov_to_movi.\n", op); + tcg_abort(); + } +} + +/* Reset TEMP's state to TCG_TEMP_ANY. If TEMP was a representative of some + class of equivalent temp's, a new representative should be chosen in this + class. */ +static void reset_temp(tcg_temp_state *state, tcg_target_ulong *vals, + TCGArg temp, int nb_temps, int nb_globals) +{ + int i; + TCGArg new_base; + new_base = (TCGArg)-1; + for (i = nb_globals; i < nb_temps; i++) { + if (state[i] == TCG_TEMP_COPY && vals[i] == temp) { + if (new_base == ((TCGArg)-1)) { + new_base = (TCGArg)i; + state[i] = TCG_TEMP_ANY; + } else { + vals[i] = new_base; + } + } + } + for (i = 0; i < nb_globals; i++) { + if (state[i] == TCG_TEMP_COPY && vals[i] == temp) { + if (new_base == ((TCGArg)-1)) { + state[i] = TCG_TEMP_ANY; + } else { + vals[i] = new_base; + } + } + } + state[temp] = TCG_TEMP_ANY; +} + +/* Propagate constants and copies, fold constant expressions. */ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr, TCGArg *args, TCGOpDef *tcg_op_defs) { int i, nb_ops, op_index, op, nb_temps, nb_globals; const TCGOpDef *def; TCGArg *gen_args; + /* Array VALS has an element for each temp. + If this temp holds a constant then its value is kept in VALS' element. + If this temp is a copy of other ones then this equivalence class' + representative is kept in VALS' element. + If this temp is neither copy nor constant then corresponding VALS' + element is unused. */ + static tcg_target_ulong vals[TCG_MAX_TEMPS]; + static tcg_temp_state state[TCG_MAX_TEMPS]; nb_temps = s->nb_temps; nb_globals = s->nb_globals; + memset(state, 0, nb_temps * sizeof(tcg_temp_state)); nb_ops = tcg_opc_ptr - gen_opc_buf; gen_args = args; for (op_index = 0; op_index < nb_ops; op_index++) { op = gen_opc_buf[op_index]; def = &tcg_op_defs[op]; + /* Do copy propagation */ + if (op != INDEX_op_call) { + for (i = def->nb_oargs; i < def->nb_oargs + def->nb_iargs; i++) { + if (state[args[i]] == TCG_TEMP_COPY + && !(def->args_ct[i].ct & TCG_CT_IALIAS) + && (def->args_ct[i].ct & TCG_CT_REG)) { + args[i] = vals[args[i]]; + } + } + } + + /* Propagate constants through copy operations and do constant + folding. Constants will be substituted to arguments by register + allocator where needed and possible. Also detect copies. */ switch (op) { + case INDEX_op_mov_i32: +#if TCG_TARGET_REG_BITS == 64 + case INDEX_op_mov_i64: +#endif + if ((state[args[1]] == TCG_TEMP_COPY + && vals[args[1]] == args[0]) + || args[0] == args[1]) { + args += 2; + gen_opc_buf[op_index] = INDEX_op_nop; + break; + } + if (state[args[1]] != TCG_TEMP_CONST) { + reset_temp(state, vals, args[0], nb_temps, nb_globals); + if (args[1] >= s->nb_globals) { + state[args[0]] = TCG_TEMP_COPY; + vals[args[0]] = args[1]; + } + gen_args[0] = args[0]; + gen_args[1] = args[1]; + gen_args += 2; + args += 2; + break; + } else { + /* Source argument is constant. Rewrite the operation and + let movi case handle it. */ + op = mov_to_movi(op); + gen_opc_buf[op_index] = op; + args[1] = vals[args[1]]; + /* fallthrough */ + } + case INDEX_op_movi_i32: +#if TCG_TARGET_REG_BITS == 64 + case INDEX_op_movi_i64: +#endif + reset_temp(state, vals, args[0], nb_temps, nb_globals); + state[args[0]] = TCG_TEMP_CONST; + vals[args[0]] = args[1]; + gen_args[0] = args[0]; + gen_args[1] = args[1]; + gen_args += 2; + args += 2; + break; case INDEX_op_call: case INDEX_op_jmp: case INDEX_op_br: @@ -55,6 +172,7 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr, #if TCG_TARGET_REG_BITS == 64 case INDEX_op_brcond_i64: #endif + memset(state, 0, nb_temps * sizeof(tcg_temp_state)); i = (op == INDEX_op_call) ? (args[0] >> 16) + (args[0] & 0xffff) + 3 : def->nb_args; @@ -66,6 +184,11 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr, } break; default: + /* Default case: we do know nothing about operation so no + propagation is done. We only trash output args. */ + for (i = 0; i < def->nb_oargs; i++) { + reset_temp(state, vals, args[i], nb_temps, nb_globals); + } for (i = 0; i < def->nb_args; i++) { gen_args[i] = args[i]; }