From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:35409) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TJ7H9-0003xb-TC for qemu-devel@nongnu.org; Tue, 02 Oct 2012 14:33:05 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TJ7H8-0007aF-HN for qemu-devel@nongnu.org; Tue, 02 Oct 2012 14:32:59 -0400 Received: from mail-pb0-f45.google.com ([209.85.160.45]:48337) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TJ7H8-0007WF-Ap for qemu-devel@nongnu.org; Tue, 02 Oct 2012 14:32:58 -0400 Received: by mail-pb0-f45.google.com with SMTP id rp2so9147813pbb.4 for ; Tue, 02 Oct 2012 11:32:57 -0700 (PDT) Sender: Richard Henderson From: Richard Henderson Date: Tue, 2 Oct 2012 11:32:21 -0700 Message-Id: <1349202750-16815-2-git-send-email-rth@twiddle.net> In-Reply-To: <1349202750-16815-1-git-send-email-rth@twiddle.net> References: <1349202750-16815-1-git-send-email-rth@twiddle.net> Subject: [Qemu-devel] [PATCH 01/10] tcg: Split out swap_commutative as a subroutine List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Aurelien Jarno Reduces code duplication and prefers movcond d, c1, c2, const, s to movcond d, c1, c2, s, const It also prefers add r, r, c over add r, c, r when both inputs are known constants. This doesn't matter for true add, as we will fully constant fold that. But it matters for a follow-on patch using this routine for add2 which may not be fully foldable. Signed-off-by: Richard Henderson --- tcg/optimize.c | 56 ++++++++++++++++++++++++-------------------------------- 1 file changed, 24 insertions(+), 32 deletions(-) diff --git a/tcg/optimize.c b/tcg/optimize.c index 35532a1..5e0504a 100644 --- a/tcg/optimize.c +++ b/tcg/optimize.c @@ -382,6 +382,23 @@ static TCGArg do_constant_folding_cond(TCGOpcode op, TCGArg x, tcg_abort(); } +static bool swap_commutative(TCGArg dest, TCGArg *p1, TCGArg *p2) +{ + TCGArg a1 = *p1, a2 = *p2; + int sum = 0; + sum += temps[a1].state == TCG_TEMP_CONST; + sum -= temps[a2].state == TCG_TEMP_CONST; + + /* Prefer the constant in second argument, and then the form + op a, a, b, which is better handled on non-RISC hosts. */ + if (sum > 0 || (sum == 0 && dest == a2)) { + *p1 = a2; + *p2 = a1; + return true; + } + return false; +} + /* 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) @@ -391,7 +408,6 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr, const TCGOpDef *def; TCGArg *gen_args; TCGArg tmp; - TCGCond cond; /* Array VALS has an element for each temp. If this temp holds a constant then its value is kept in VALS' element. @@ -434,52 +450,28 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr, CASE_OP_32_64(eqv): CASE_OP_32_64(nand): CASE_OP_32_64(nor): - /* Prefer the constant in second argument, and then the form - op a, a, b, which is better handled on non-RISC hosts. */ - if (temps[args[1]].state == TCG_TEMP_CONST || (args[0] == args[2] - && temps[args[2]].state != TCG_TEMP_CONST)) { - tmp = args[1]; - args[1] = args[2]; - args[2] = tmp; - } + swap_commutative(args[0], &args[1], &args[2]); break; CASE_OP_32_64(brcond): - if (temps[args[0]].state == TCG_TEMP_CONST - && temps[args[1]].state != TCG_TEMP_CONST) { - tmp = args[0]; - args[0] = args[1]; - args[1] = tmp; + if (swap_commutative(-1, &args[0], &args[1])) { args[2] = tcg_swap_cond(args[2]); } break; CASE_OP_32_64(setcond): - if (temps[args[1]].state == TCG_TEMP_CONST - && temps[args[2]].state != TCG_TEMP_CONST) { - tmp = args[1]; - args[1] = args[2]; - args[2] = tmp; + if (swap_commutative(args[0], &args[1], &args[2])) { args[3] = tcg_swap_cond(args[3]); } break; CASE_OP_32_64(movcond): - cond = args[5]; - if (temps[args[1]].state == TCG_TEMP_CONST - && temps[args[2]].state != TCG_TEMP_CONST) { - tmp = args[1]; - args[1] = args[2]; - args[2] = tmp; - cond = tcg_swap_cond(cond); + if (swap_commutative(-1, &args[1], &args[2])) { + args[5] = tcg_swap_cond(args[5]); } /* For movcond, we canonicalize the "false" input reg to match the destination reg so that the tcg backend can implement a "move if true" operation. */ - if (args[0] == args[3]) { - tmp = args[3]; - args[3] = args[4]; - args[4] = tmp; - cond = tcg_invert_cond(cond); + if (swap_commutative(args[0], &args[4], &args[3])) { + args[5] = tcg_invert_cond(args[5]); } - args[5] = cond; default: break; } -- 1.7.11.4