Reported-by: Dibyendu Majumdar <mobile@xxxxxxxxxxxxxxx>
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@xxxxxxxxx>
---
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
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