From mboxrd@z Thu Jan 1 00:00:00 1970 From: Luc Van Oostenryck Subject: [PATCH 3/3] simplify ((A & M') | B ) & M when M' & M == 0 Date: Mon, 7 Aug 2017 03:33:38 +0200 Message-ID: <20170807013338.46211-4-luc.vanoostenryck@gmail.com> References: <20170807013338.46211-1-luc.vanoostenryck@gmail.com> Return-path: Received: from mail-wm0-f65.google.com ([74.125.82.65]:33217 "EHLO mail-wm0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751426AbdHGBdv (ORCPT ); Sun, 6 Aug 2017 21:33:51 -0400 Received: by mail-wm0-f65.google.com with SMTP id q189so12145653wmd.0 for ; Sun, 06 Aug 2017 18:33:50 -0700 (PDT) In-Reply-To: <20170807013338.46211-1-luc.vanoostenryck@gmail.com> Sender: linux-sparse-owner@vger.kernel.org List-Id: linux-sparse@vger.kernel.org To: Dibyendu Majumdar Cc: linux-sparse@vger.kernel.org, Luc Van Oostenryck Reported-by: Dibyendu Majumdar Signed-off-by: Luc Van Oostenryck --- simplify.c | 42 +++++++++++++++++++++++++++++++++++++++++- 1 file changed, 41 insertions(+), 1 deletion(-) diff --git a/simplify.c b/simplify.c index cfb6b2cda..3fb2c8d8f 100644 --- a/simplify.c +++ b/simplify.c @@ -532,6 +532,46 @@ static int simplify_seteq_setne(struct instruction *insn, long long value) } } +static int simplify_and_or_mask(struct instruction *insn, pseudo_t and, pseudo_t other, unsigned long long mask) +{ + struct instruction *def = and->def; + pseudo_t old; + + if (!constant(def->src2)) + return 0; + if (def->src2->value & mask) + return 0; + old = insn->src1; + use_pseudo(insn, other, &insn->src1); + remove_usage(old, &insn->src1); + return REPEAT_CSE; +} + +static int simplify_constant_mask(struct instruction *insn, unsigned long long mask) +{ + struct instruction *left; + pseudo_t src1, src2; + + switch (def_opcode(insn->src1)) { + case OP_OR: + // Let's handle ((A & M') | B ) & M + // or (B | (A & M')) & M + // when M' & M == 0 + left = insn->src1->def; + src1 = left->src1; + src2 = left->src2; + if (def_opcode(src1) == OP_AND) + return simplify_and_or_mask(insn, src1, src2, mask); + if (def_opcode(src2) == OP_AND) + return simplify_and_or_mask(insn, src2, src1, mask); + break; + + default: + break; + } + return 0; +} + static int simplify_constant_rightside(struct instruction *insn) { long long value = insn->src2->value; @@ -576,7 +616,7 @@ static int simplify_constant_rightside(struct instruction *insn) case OP_AND: if (!value) return replace_with_pseudo(insn, insn->src2); - return 0; + return simplify_constant_mask(insn, value); case OP_SET_NE: case OP_SET_EQ: -- 2.13.2