From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44330) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1e5gap-0005uN-T0 for qemu-devel@nongnu.org; Fri, 20 Oct 2017 19:20:44 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1e5gao-0007bF-Ud for qemu-devel@nongnu.org; Fri, 20 Oct 2017 19:20:43 -0400 Received: from mail-pf0-x242.google.com ([2607:f8b0:400e:c00::242]:47093) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1e5gao-0007b1-OM for qemu-devel@nongnu.org; Fri, 20 Oct 2017 19:20:42 -0400 Received: by mail-pf0-x242.google.com with SMTP id p87so13073074pfj.3 for ; Fri, 20 Oct 2017 16:20:42 -0700 (PDT) From: Richard Henderson Date: Fri, 20 Oct 2017 16:19:41 -0700 Message-Id: <20171020232023.15010-11-richard.henderson@linaro.org> In-Reply-To: <20171020232023.15010-1-richard.henderson@linaro.org> References: <20171020232023.15010-1-richard.henderson@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Subject: [Qemu-devel] [PATCH v7 10/52] tcg: Avoid loops against variable bounds List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: cota@braap.org, f4bug@amsat.org, pbonzini@redhat.com, Richard Henderson From: Richard Henderson Copy s->nb_globals or s->nb_temps to a local variable for the purposes of iteration. This should allow the compiler to use low-overhead looping constructs on some hosts. Reviewed-by: Emilio G. Cota Reviewed-by: Alex Bennée Signed-off-by: Richard Henderson --- tcg/tcg.c | 27 ++++++++++----------------- 1 file changed, 10 insertions(+), 17 deletions(-) diff --git a/tcg/tcg.c b/tcg/tcg.c index d08e34a9d8..840e65c0d4 100644 --- a/tcg/tcg.c +++ b/tcg/tcg.c @@ -1159,23 +1159,16 @@ void tcg_gen_callN(TCGContext *s, void *func, TCGArg ret, static void tcg_reg_alloc_start(TCGContext *s) { - int i; + int i, n; TCGTemp *ts; - for(i = 0; i < s->nb_globals; i++) { + + for (i = 0, n = s->nb_globals; i < n; i++) { ts = &s->temps[i]; - if (ts->fixed_reg) { - ts->val_type = TEMP_VAL_REG; - } else { - ts->val_type = TEMP_VAL_MEM; - } + ts->val_type = (ts->fixed_reg ? TEMP_VAL_REG : TEMP_VAL_MEM); } - for(i = s->nb_globals; i < s->nb_temps; i++) { + for (n = s->nb_temps; i < n; i++) { ts = &s->temps[i]; - if (ts->temp_local) { - ts->val_type = TEMP_VAL_MEM; - } else { - ts->val_type = TEMP_VAL_DEAD; - } + ts->val_type = (ts->temp_local ? TEMP_VAL_MEM : TEMP_VAL_DEAD); ts->mem_allocated = 0; ts->fixed_reg = 0; } @@ -2277,9 +2270,9 @@ static void temp_save(TCGContext *s, TCGTemp *ts, TCGRegSet allocated_regs) temporary registers needs to be allocated to store a constant. */ static void save_globals(TCGContext *s, TCGRegSet allocated_regs) { - int i; + int i, n; - for (i = 0; i < s->nb_globals; i++) { + for (i = 0, n = s->nb_globals; i < n; i++) { temp_save(s, &s->temps[i], allocated_regs); } } @@ -2289,9 +2282,9 @@ static void save_globals(TCGContext *s, TCGRegSet allocated_regs) temporary registers needs to be allocated to store a constant. */ static void sync_globals(TCGContext *s, TCGRegSet allocated_regs) { - int i; + int i, n; - for (i = 0; i < s->nb_globals; i++) { + for (i = 0, n = s->nb_globals; i < n; i++) { TCGTemp *ts = &s->temps[i]; tcg_debug_assert(ts->val_type != TEMP_VAL_REG || ts->fixed_reg -- 2.13.6