diff mbox series

[7/7] not: simplify ((x cmp y) {&,|,^} (x !cmp y)) --> {0,1,1}

Message ID 20201122152731.10994-8-luc.vanoostenryck@gmail.com (mailing list archive)
State Mainlined, archived
Headers show
Series simplify logical negation | expand

Commit Message

Luc Van Oostenryck Nov. 22, 2020, 3:27 p.m. UTC 
Simplify bitwise operations on a compare and its complement
into 0 (for &) or 1 for (| and ^).

Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
---
 simplify.c                   | 24 +++++++++++++++++++++---
 validation/optim/cse-not02.c |  1 -
 2 files changed, 21 insertions(+), 4 deletions(-)
diff mbox series

Patch

diff --git a/simplify.c b/simplify.c
index b41c155735d1..9938a5974744 100644
--- a/simplify.c
+++ b/simplify.c
@@ -1632,7 +1632,7 @@  static int simplify_compare(struct instruction *insn)
 
 static int simplify_and_one_side(struct instruction *insn, pseudo_t *p1, pseudo_t *p2)
 {
-	struct instruction *def;
+	struct instruction *def, *defr = NULL;
 	pseudo_t src1 = *p1;
 
 	switch (DEF_OPCODE(def, src1)) {
@@ -1640,6 +1640,12 @@  static int simplify_and_one_side(struct instruction *insn, pseudo_t *p1, pseudo_
 		if (def->src == *p2)
 			return replace_with_value(insn, 0);
 		break;
+	case OP_BINCMP ... OP_BINCMP_END:
+		if (DEF_OPCODE(defr, *p2) == opcode_negate(def->opcode)) {
+			if (def->src1 == defr->src1 && def->src2 == defr->src2)
+				return replace_with_value(insn, 0);
+		}
+		break;
 	}
 	return 0;
 }
@@ -1652,7 +1658,7 @@  static int simplify_and(struct instruction *insn)
 
 static int simplify_ior_one_side(struct instruction *insn, pseudo_t *p1, pseudo_t *p2)
 {
-	struct instruction *def;
+	struct instruction *def, *defr = NULL;
 	pseudo_t src1 = *p1;
 
 	switch (DEF_OPCODE(def, src1)) {
@@ -1660,6 +1666,12 @@  static int simplify_ior_one_side(struct instruction *insn, pseudo_t *p1, pseudo_
 		if (def->src == *p2)
 			return replace_with_value(insn, bits_mask(insn->size));
 		break;
+	case OP_BINCMP ... OP_BINCMP_END:
+		if (DEF_OPCODE(defr, *p2) == opcode_negate(def->opcode)) {
+			if (def->src1 == defr->src1 && def->src2 == defr->src2)
+				return replace_with_value(insn, 1);
+		}
+		break;
 	}
 	return 0;
 }
@@ -1672,7 +1684,7 @@  static int simplify_ior(struct instruction *insn)
 
 static int simplify_xor_one_side(struct instruction *insn, pseudo_t *p1, pseudo_t *p2)
 {
-	struct instruction *def;
+	struct instruction *def, *defr = NULL;
 	pseudo_t src1 = *p1;
 
 	switch (DEF_OPCODE(def, src1)) {
@@ -1680,6 +1692,12 @@  static int simplify_xor_one_side(struct instruction *insn, pseudo_t *p1, pseudo_
 		if (def->src == *p2)
 			return replace_with_value(insn, bits_mask(insn->size));
 		break;
+	case OP_BINCMP ... OP_BINCMP_END:
+		if (DEF_OPCODE(defr, *p2) == opcode_negate(def->opcode)) {
+			if (def->src1 == defr->src1 && def->src2 == defr->src2)
+				return replace_with_value(insn, 1);
+		}
+		break;
 	}
 	return 0;
 }
diff --git a/validation/optim/cse-not02.c b/validation/optim/cse-not02.c
index aa54a375a9ea..70addebcfbb6 100644
--- a/validation/optim/cse-not02.c
+++ b/validation/optim/cse-not02.c
@@ -5,7 +5,6 @@  int xor(int a, int b) { return ((a == b) ^ (a != b)) == 1; }
 /*
  * check-name: cse-not02
  * check-command: test-linearize -Wno-decl $file
- * check-known-to-fail
  *
  * check-output-ignore
  * check-output-returns: 1