diff mbox series

[05/10] cmps: simplify signed compares with SMIN or SMAX

Message ID 20210126220432.58265-6-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 
Simplify away signed compares with SMIN or SMAX which can be
statically be determined to be always true or always false.

Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
---
 simplify.c                     | 17 +++++++++++++++++
 validation/optim/cmps-minmax.c |  1 -
 2 files changed, 17 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/simplify.c b/simplify.c
index a306828c1c4b..096742d51a16 100644
--- a/simplify.c
+++ b/simplify.c
@@ -1170,6 +1170,23 @@  static int simplify_compare_constant(struct instruction *insn, long long value)
 	int changed = 0;
 
 	switch (insn->opcode) {
+	case OP_SET_LT:
+		if (value == sign_bit(size))	// (x <  SMIN) --> 0
+			return replace_with_pseudo(insn, value_pseudo(0));
+		break;
+	case OP_SET_LE:
+		if (value == sign_mask(size))	// (x <= SMAX) --> 1
+			return replace_with_pseudo(insn, value_pseudo(1));
+		break;
+	case OP_SET_GE:
+		if (value == sign_bit(size))	// (x >= SMIN) --> 1
+			return replace_with_pseudo(insn, value_pseudo(1));
+		break;
+	case OP_SET_GT:
+		if (value == sign_mask(size))	// (x >  SMAX) --> 0
+			return replace_with_pseudo(insn, value_pseudo(0));
+		break;
+
 	case OP_SET_B:
 		if (!value)			// (x < 0) --> 0
 			return replace_with_pseudo(insn, value_pseudo(0));
diff --git a/validation/optim/cmps-minmax.c b/validation/optim/cmps-minmax.c
index ded3286cf752..5802cdbcafd1 100644
--- a/validation/optim/cmps-minmax.c
+++ b/validation/optim/cmps-minmax.c
@@ -10,7 +10,6 @@  int gt_smax(int a) { return (a >  SMAX) == 0; }
 /*
  * check-name: cmps-minmax
  * check-command: test-linearize -Wno-decl $file
- * check-known-to-fail
  *
  * check-output-ignore
  * check-output-returns: 1