aboutsummaryrefslogtreecommitdiffstatshomepage
path: root/simplify.c
diff options
authorLuc Van Oostenryck <luc.vanoostenryck@gmail.com>2020-09-27 16:45:08 +0200
committerLuc Van Oostenryck <luc.vanoostenryck@gmail.com>2020-10-20 22:35:43 +0200
commitdbe0117ce6246725eaacc6ed3cb2b2c3ee14d1cc (patch)
treec90142b50bfc532a8e9f34881e72cb70ea749e07 /simplify.c
parent43a7dfa578c3ce08e636866220ac9142772e0dd9 (diff)
downloadsparse-dev-dbe0117ce6246725eaacc6ed3cb2b2c3ee14d1cc.tar.gz
sub: simplify x - (x + y) --> -y
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Diffstat (limited to 'simplify.c')
-rw-r--r--simplify.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/simplify.c b/simplify.c
index 08b706ca..48bf48d2 100644
--- a/simplify.c
+++ b/simplify.c
@@ -1396,6 +1396,10 @@ static int simplify_sub(struct instruction *insn)
}
switch (DEF_OPCODE(def, src2)) {
+ case OP_ADD:
+ if (src1 == def->src1) // x - (x + z) --> -z
+ return replace_with_unop(insn, OP_NEG, def->src2);
+ break;
case OP_NEG: // (x - -y) --> (x + y)
insn->opcode = OP_ADD;
return replace_pseudo(insn, &insn->src2, def->src);