[15/22] add: simplify (x + -y) --> (x - y)

Message ID	20201020211021.82394-16-luc.vanoostenryck@gmail.com (mailing list archive)
State	Mainlined, archived
Headers	show Return-Path: <SRS0=cyFV=D3=vger.kernel.org=linux-sparse-owner@kernel.org> From: Luc Van Oostenryck <luc.vanoostenryck@gmail.com> To: linux-sparse@vger.kernel.org Cc: Luc Van Oostenryck <luc.vanoostenryck@gmail.com> Subject: [PATCH 15/22] add: simplify (x + -y) --> (x - y) Date: Tue, 20 Oct 2020 23:10:14 +0200 Message-Id: <20201020211021.82394-16-luc.vanoostenryck@gmail.com> In-Reply-To: <20201020211021.82394-1-luc.vanoostenryck@gmail.com> References: <20201020211021.82394-1-luc.vanoostenryck@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	essential OP_ADD & OP_SUB simplifications \| expand [00/22] essential OP_ADD & OP_SUB simplifications [01/22] add testcases about OP_ADD & OP_SUB simplifications [02/22] let switch_pseudo() return REPEAT_CSE [03/22] extract eval_op() from eval_insn() [04/22] unop: add helper eval_unop() [05/22] unop: add helper replace_with_unop() [06/22] add a flag to identify commutative & associative ops [07/22] constants must be truncated to the operation's size [08/22] reassoc: simplify (x # C) # K --> x # eval(C # K) [09/22] sub: reorganize handling of OP_{ADD,SUB}s with constant rightside [10/22] sub: canonicalize (0 - x) into -x [11/22] sub: simplify C - (y + D) --> eval(C-D) - y [12/22] sub: simplify C - (D - z) --> z + eval(C-D) [13/22] sub: simplify (C - y) + D --> eval(C+D) - y [14/22] sub: simplify (x - -y) --> (x + y) [15/22] add: simplify (x + -y) --> (x - y) [16/22] add: simplify (-x + y) --> (y - x) [17/22] sub: simplify (x + y) - x --> y [18/22] sub: simplify (x + y) - y --> x [19/22] sub: simplify x - (x + y) --> -y [20/22] sub: simplify x - (y + x) --> -y [21/22] sub: simplify (x - y) + y --> x [22/22] sub: simplify x + (y - x) --> y

Message ID

20201020211021.82394-16-luc.vanoostenryck@gmail.com (mailing list archive)

State

Mainlined, archived

Headers

From: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
To: linux-sparse@vger.kernel.org
Cc: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Subject: [PATCH 15/22] add: simplify (x + -y) --> (x - y)
Date: Tue, 20 Oct 2020 23:10:14 +0200
Message-Id: <20201020211021.82394-16-luc.vanoostenryck@gmail.com>
In-Reply-To: <20201020211021.82394-1-luc.vanoostenryck@gmail.com>
References: <20201020211021.82394-1-luc.vanoostenryck@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Series

essential OP_ADD & OP_SUB simplifications | expand

Commit Message

Luc Van Oostenryck Oct. 20, 2020, 9:10 p.m. UTC

Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
---
 simplify.c                          | 16 +++++++++++++++-
 validation/optim/simplify-add-neg.c |  1 -
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/simplify.c b/simplify.c
index fa7e1679d7ac..f8a0ba726561 100644
--- a/simplify.c
+++ b/simplify.c
@@ -1358,6 +1358,20 @@  static int simplify_associative_binop(struct instruction *insn)
 	return REPEAT_CSE;
 }
 
+static int simplify_add(struct instruction *insn)
+{
+	pseudo_t src2 = insn->src2;
+	struct instruction *def;
+
+	switch (DEF_OPCODE(def, src2)) {
+	case OP_NEG:				// (x + -y) --> (x - y)
+		insn->opcode = OP_SUB;
+		return replace_pseudo(insn, &insn->src2, def->src);
+	}
+
+	return 0;
+}
+
 static int simplify_sub(struct instruction *insn)
 {
 	pseudo_t src2 = insn->src2;
@@ -1832,8 +1846,8 @@  int simplify_instruction(struct instruction *insn)
 	}
 
 	switch (insn->opcode) {
+	case OP_ADD: return simplify_add(insn);
 	case OP_SUB: return simplify_sub(insn);
-	case OP_ADD:
 	case OP_MUL:
 	case OP_AND:
 	case OP_OR:
diff --git a/validation/optim/simplify-add-neg.c b/validation/optim/simplify-add-neg.c
index 19b64b096567..c24b8e19e5c3 100644
--- a/validation/optim/simplify-add-neg.c
+++ b/validation/optim/simplify-add-neg.c
@@ -3,7 +3,6 @@  int add_neg(int x, int y) { return x + -y; }
 /*
  * check-name: simplify-add-neg
  * check-command: test-linearize -Wno-decl $file
- * check-known-to-fail
  *
  * check-output-ignore
  * check-output-contains: sub\\..*%arg1, %arg2

[15/22] add: simplify (x + -y) --> (x - y)

Commit Message

Patch