From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49752) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZKTya-0004p2-8B for qemu-devel@nongnu.org; Wed, 29 Jul 2015 12:13:05 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZKTyX-0007cC-2P for qemu-devel@nongnu.org; Wed, 29 Jul 2015 12:13:04 -0400 Received: from mail-wi0-f176.google.com ([209.85.212.176]:38864) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZKTyW-0007c0-QC for qemu-devel@nongnu.org; Wed, 29 Jul 2015 12:13:01 -0400 Received: by wibxm9 with SMTP id xm9so33572573wib.1 for ; Wed, 29 Jul 2015 09:13:00 -0700 (PDT) References: <1437755447-10537-1-git-send-email-aurelien@aurel32.net> <1437755447-10537-5-git-send-email-aurelien@aurel32.net> From: Alex =?utf-8?Q?Benn=C3=A9e?= In-reply-to: <1437755447-10537-5-git-send-email-aurelien@aurel32.net> Date: Wed, 29 Jul 2015 17:12:57 +0100 Message-ID: <87k2tjlz7a.fsf@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] [PATCH for-2.5 04/10] tcg/optimize: allow constant to have copies List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Aurelien Jarno Cc: qemu-devel@nongnu.org, Richard Henderson Aurelien Jarno writes: > Now that copies and constants are tracked separately, we can allow > constant to have copies, deferring the choice to use a register or a > constant to the register allocation pass. This prevent this kind of > regular constant reloading: > > -OUT: [size=338] > +OUT: [size=298] > mov -0x4(%r14),%ebp > test %ebp,%ebp > jne 0x7ffbe9cb0ed6 > mov $0x40002219f8,%rbp > mov %rbp,(%r14) > - mov $0x40002219f8,%rbp > mov $0x4000221a20,%rbx > mov %rbp,(%rbx) > mov $0x4000000000,%rbp > mov %rbp,(%r14) > - mov $0x4000000000,%rbp > mov $0x4000221d38,%rbx > mov %rbp,(%rbx) > mov $0x40002221a8,%rbp > mov %rbp,(%r14) > - mov $0x40002221a8,%rbp > mov $0x4000221d40,%rbx > mov %rbp,(%rbx) > mov $0x4000019170,%rbp > mov %rbp,(%r14) > - mov $0x4000019170,%rbp > mov $0x4000221d48,%rbx > mov %rbp,(%rbx) > mov $0x40000049ee,%rbp > mov %rbp,0x80(%r14) > mov %r14,%rdi > callq 0x7ffbe99924d0 > mov $0x4000001680,%rbp > mov %rbp,0x30(%r14) > mov 0x10(%r14),%rbp > mov $0x4000001680,%rbp > mov %rbp,0x30(%r14) > mov 0x10(%r14),%rbp > shl $0x20,%rbp > mov (%r14),%rbx > mov %ebx,%ebx > mov %rbx,(%r14) > or %rbx,%rbp > mov %rbp,0x10(%r14) > mov %rbp,0x90(%r14) > mov 0x60(%r14),%rbx > mov %rbx,0x38(%r14) > mov 0x28(%r14),%rbx > mov $0x4000220e60,%r12 > mov %rbx,(%r12) > mov $0x40002219c8,%rbx > mov %rbp,(%rbx) > mov 0x20(%r14),%rbp > sub $0x8,%rbp > mov $0x4000004a16,%rbx > mov %rbx,0x0(%rbp) > mov %rbp,0x20(%r14) > mov $0x19,%ebp > mov %ebp,0xa8(%r14) > mov $0x4000015110,%rbp > mov %rbp,0x80(%r14) > xor %eax,%eax > jmpq 0x7ffbebcae426 > lea -0x5f6d72a(%rip),%rax # 0x7ffbe3d437b3 > jmpq 0x7ffbebcae426 > > Cc: Richard Henderson > Signed-off-by: Aurelien Jarno > --- > tcg/optimize.c | 11 ++--------- > 1 file changed, 2 insertions(+), 9 deletions(-) > > diff --git a/tcg/optimize.c b/tcg/optimize.c > index f16eb1e..48103b2 100644 > --- a/tcg/optimize.c > +++ b/tcg/optimize.c > @@ -237,11 +237,6 @@ static void tcg_opt_gen_mov(TCGContext *s, TCGOp *op, TCGArg *args, > return; > } > > - if (temp_is_const(src)) { > - tcg_opt_gen_movi(s, op, args, dst, temps[src].val); > - return; > - } > - That looks suspicious, surely we only want to drop the move if we already have the const somewhere else? > TCGOpcode new_op = op_to_mov(op->opc); > tcg_target_ulong mask; > > @@ -255,17 +250,15 @@ static void tcg_opt_gen_mov(TCGContext *s, TCGOp *op, TCGArg *args, > } > temps[dst].mask = mask; > > - assert(!temp_is_const(src)); > - > if (s->temps[src].type == s->temps[dst].type) { > if (!temp_is_copy(src)) { > - temps[src].is_const = false; > temps[src].is_copy = true; > temps[src].next_copy = src; > temps[src].prev_copy = src; > } > - temps[dst].is_const = false; > + temps[dst].is_const = temps[src].is_const; > temps[dst].is_copy = true; > + temps[dst].val = temps[src].val; > temps[dst].next_copy = temps[src].next_copy; > temps[dst].prev_copy = src; > temps[temps[dst].next_copy].prev_copy = dst; -- Alex Bennée