[PATCH 09/16] cmp: canonicalize unsigned (x {<=,>} SMAX)

[Luc Van Oostenryck <luc.vanoostenryck@gmail.com>]

Unsigned <= or > against SMAX are equivalent to testing if the
value is positive or not (when interpreted as a signed number).

Canonicalize to this positive/negative test since it only needs
the constant 0 which make it easier to handle at later steps.

Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
---
 simplify.c                   | 4 ++++
 validation/optim/set-uimm3.c | 1 -
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/simplify.c b/simplify.c
index 7921300f7280..2176f90dc133 100644
--- a/simplify.c
+++ b/simplify.c
@@ -1112,6 +1112,8 @@ static int simplify_compare_constant(struct instruction *insn, long long value)
 			return replace_with_pseudo(insn, value_pseudo(1));
 		if (value == (bits - 1))	// (x <= ~1) --> (x != ~0)
 			return replace_binop_value(insn, OP_SET_NE, bits);
+		if (value == (bits >> 1))	// (x u<= SMAX) --> (x s>= 0)
+			changed |= replace_binop_value(insn, OP_SET_GE, 0);
 		break;
 	case OP_SET_A:
 		if (!value)			// (x > 0) --> (x != 0)
@@ -1120,6 +1122,8 @@ static int simplify_compare_constant(struct instruction *insn, long long value)
 			return replace_with_pseudo(insn, value_pseudo(0));
 		if (value == (bits - 1))	// (x > ~1) --> (x == ~0)
 			return replace_binop_value(insn, OP_SET_EQ, bits);
+		if (value == (bits >> 1))	// (x u> SMAX) --> (x s< 0)
+			changed |= replace_binop_value(insn, OP_SET_LT, 0);
 		break;
 	}
 	return changed;
diff --git a/validation/optim/set-uimm3.c b/validation/optim/set-uimm3.c
index b72ef8d6e819..5160f741d85b 100644
--- a/validation/optim/set-uimm3.c
+++ b/validation/optim/set-uimm3.c
@@ -4,7 +4,6 @@ int gt(int x) { return (x >  0x7fffffffU) == (x <  0); }
 /*
  * check-name: set-uimm3
  * check-command: test-linearize -Wno-decl $file
- * check-known-to-fail
  *
  * check-output-ignore
  * check-output-returns: 1
-- 
2.29.2