From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50637) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W9FNq-0000Ah-9l for qemu-devel@nongnu.org; Fri, 31 Jan 2014 09:48:00 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1W9FNk-0007KZ-GZ for qemu-devel@nongnu.org; Fri, 31 Jan 2014 09:47:54 -0500 Received: from mail-qc0-x235.google.com ([2607:f8b0:400d:c01::235]:45410) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W9FNk-0007KP-Bv for qemu-devel@nongnu.org; Fri, 31 Jan 2014 09:47:48 -0500 Received: by mail-qc0-f181.google.com with SMTP id e9so7048736qcy.40 for ; Fri, 31 Jan 2014 06:47:47 -0800 (PST) Sender: Richard Henderson From: Richard Henderson Date: Fri, 31 Jan 2014 08:47:00 -0600 Message-Id: <1391179623-13626-6-git-send-email-rth@twiddle.net> In-Reply-To: <1391179623-13626-1-git-send-email-rth@twiddle.net> References: <1391179623-13626-1-git-send-email-rth@twiddle.net> Subject: [Qemu-devel] [PATCH 5/8] tcg/optimize: Handle known-zeros masks for ANDC List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: aurelien@aurel32.net Signed-off-by: Richard Henderson --- tcg/optimize.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/tcg/optimize.c b/tcg/optimize.c index d3b099a..3291a08 100644 --- a/tcg/optimize.c +++ b/tcg/optimize.c @@ -727,6 +727,17 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr, mask = temps[args[1]].mask & mask; break; + CASE_OP_32_64(andc): + /* Known-zeros does not imply known-ones. Therefore unless + args[2] is constant, we can't infer anything from it. */ + if (temps[args[2]].state == TCG_TEMP_CONST) { + mask = ~temps[args[2]].mask; + goto and_const; + } + /* But we certainly know nothing outside args[1] may be set. */ + mask = temps[args[1]].mask; + break; + case INDEX_op_sar_i32: if (temps[args[2]].state == TCG_TEMP_CONST) { mask = (int32_t)temps[args[1]].mask >> temps[args[2]].val; -- 1.8.5.3