From mboxrd@z Thu Jan 1 00:00:00 1970 From: Luc Van Oostenryck Subject: [PATCH v2 5/8] simplify ((A & M') | B ) & M when M' & M == 0 Date: Mon, 7 Aug 2017 21:12:02 +0200 Message-ID: <20170807191205.86590-6-luc.vanoostenryck@gmail.com> References: <20170807191205.86590-1-luc.vanoostenryck@gmail.com> Return-path: Received: from mail-wm0-f68.google.com ([74.125.82.68]:38347 "EHLO mail-wm0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751508AbdHGTMQ (ORCPT ); Mon, 7 Aug 2017 15:12:16 -0400 Received: by mail-wm0-f68.google.com with SMTP id y206so2036217wmd.5 for ; Mon, 07 Aug 2017 12:12:16 -0700 (PDT) In-Reply-To: <20170807191205.86590-1-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 This is specially usefull when A is in fact undefined. Reported-by: Dibyendu Majumdar Signed-off-by: Luc Van Oostenryck --- simplify.c | 42 +++++++++++++++++++++- validation/optim/store-load-bitfield.c | 66 ++++++++++++++++++++++++++++++++++ 2 files changed, 107 insertions(+), 1 deletion(-) create mode 100644 validation/optim/store-load-bitfield.c diff --git a/simplify.c b/simplify.c index 8b63bcaff..9893613da 100644 --- a/simplify.c +++ b/simplify.c @@ -502,6 +502,46 @@ 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; @@ -546,7 +586,7 @@ 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: diff --git a/validation/optim/store-load-bitfield.c b/validation/optim/store-load-bitfield.c new file mode 100644 index 000000000..b74022602 --- /dev/null +++ b/validation/optim/store-load-bitfield.c @@ -0,0 +1,66 @@ +int ufoo(int a) +{ + struct u { + unsigned int :2; + unsigned int a:3; + } bf; + + bf.a = a; + return bf.a; +} + +int sfoo(int a) +{ + struct s { + signed int :2; + signed int a:3; + } bf; + + bf.a = a; + return bf.a; +} + +int xfoo(int a) +{ + struct x { + int :2; + int a:3; // unsigned ! + } bf; + + bf.a = a; + return bf.a; +} + + +/* + * check-name: optim store/load bitfields + * check-command: test-linearize -Wno-decl $file + * + * check-output-start +ufoo: +.L0: + + scast.3 %r2 <- (32) %arg1 + and.32 %r9 <- %r2, $7 + ret.32 %r9 + + +sfoo: +.L2: + + scast.3 %r13 <- (32) %arg1 + and.32 %r20 <- %r13, $7 + scast.32 %r21 <- (3) %r20 + ret.32 %r21 + + +xfoo: +.L4: + + scast.3 %r24 <- (32) %arg1 + and.32 %r31 <- %r24, $7 + ret.32 %r31 + + + * check-output-end + */ -- 2.13.2