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X-Received-From: 2a00:1450:400c:c0c::241 Subject: [Qemu-devel] [PULL 10/51] tcg: Avoid loops against variable bounds X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: peter.maydell@linaro.org, Richard Henderson Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP 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: Philippe Mathieu-Daudé 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