diff mbox series

[06/10] cmps: canonicalize signed compares with SMIN/SMAX

Message ID 20210126220432.58265-7-luc.vanoostenryck@gmail.com (mailing list archive)
State Mainlined, archived
Headers show
Series simplify and canonicalize signed compares | expand

Commit Message

Luc Van Oostenryck Jan. 26, 2021, 10:04 p.m. UTC
The remaining compares with SMIN or SMAX are equivalent to an
equality testing. For example, (x < SMAX) is the same as (x != SMAX).

Canonicalize these to the equality testing since these are usually
simpler to handle.

Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
---
 simplify.c                               | 8 ++++++++
 validation/optim/canonical-cmps-minmax.c | 1 -
 2 files changed, 8 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/simplify.c b/simplify.c
index 096742d51a16..f7c6c68d4ce9 100644
--- a/simplify.c
+++ b/simplify.c
@@ -1173,18 +1173,26 @@  static int simplify_compare_constant(struct instruction *insn, long long value)
 	case OP_SET_LT:
 		if (value == sign_bit(size))	// (x <  SMIN) --> 0
 			return replace_with_pseudo(insn, value_pseudo(0));
+		if (value == sign_mask(size))	// (x <  SMAX) --> (x != SMAX)
+			return replace_opcode(insn, OP_SET_NE);
 		break;
 	case OP_SET_LE:
 		if (value == sign_mask(size))	// (x <= SMAX) --> 1
 			return replace_with_pseudo(insn, value_pseudo(1));
+		if (value == sign_bit(size))	// (x <= SMIN) --> (x == SMIN)
+			return replace_opcode(insn, OP_SET_EQ);
 		break;
 	case OP_SET_GE:
 		if (value == sign_bit(size))	// (x >= SMIN) --> 1
 			return replace_with_pseudo(insn, value_pseudo(1));
+		if (value == sign_mask(size))	// (x >= SMAX) --> (x == SMAX)
+			return replace_opcode(insn, OP_SET_EQ);
 		break;
 	case OP_SET_GT:
 		if (value == sign_mask(size))	// (x >  SMAX) --> 0
 			return replace_with_pseudo(insn, value_pseudo(0));
+		if (value == sign_bit(size))	// (x >  SMIN) --> (x != SMIN)
+			return replace_opcode(insn, OP_SET_NE);
 		break;
 
 	case OP_SET_B:
diff --git a/validation/optim/canonical-cmps-minmax.c b/validation/optim/canonical-cmps-minmax.c
index bab09282d241..48927f49db6e 100644
--- a/validation/optim/canonical-cmps-minmax.c
+++ b/validation/optim/canonical-cmps-minmax.c
@@ -10,7 +10,6 @@  int gt_smin(int a) { return (a >  SMIN) == (a != SMIN); }
 /*
  * check-name: canonical-cmps-minmax
  * check-command: test-linearize -Wno-decl $file
- * check-known-to-fail
  *
  * check-output-ignore
  * check-output-returns: 1