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From: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
To: linux-sparse@vger.kernel.org
Cc: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Subject: [PATCH 06/10] cmps: canonicalize signed compares with SMIN/SMAX
Date: Tue, 26 Jan 2021 23:04:28 +0100	[thread overview]
Message-ID: <20210126220432.58265-7-luc.vanoostenryck@gmail.com> (raw)
In-Reply-To: <20210126220432.58265-1-luc.vanoostenryck@gmail.com>

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 --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
-- 
2.30.0


  parent reply	other threads:[~2021-01-27  3:45 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-26 22:04 [PATCH 00/10] simplify and canonicalize signed compares Luc Van Oostenryck
2021-01-26 22:04 ` [PATCH 01/10] cmps: make clearer we're using the operands' size Luc Van Oostenryck
2021-01-26 22:04 ` [PATCH 02/10] cmps: fix simplification of sext(x) + signed compare of {SMAX,SMIN} Luc Van Oostenryck
2021-01-26 22:04 ` [PATCH 03/10] cmpu: fix canonicalization of unsigned (x {<,>=} C) --> (x {<=,>} C-1) Luc Van Oostenryck
2021-01-26 22:04 ` [PATCH 04/10] cmps: add testcases for simplification of signed compares Luc Van Oostenryck
2021-01-26 22:04 ` [PATCH 05/10] cmps: simplify signed compares with SMIN or SMAX Luc Van Oostenryck
2021-01-26 22:04 ` Luc Van Oostenryck [this message]
2021-01-26 22:04 ` [PATCH 07/10] cmps: canonicalize SMIN/SMAX +- 1 --> EQ/NE Luc Van Oostenryck
2021-01-26 22:04 ` [PATCH 08/10] cmps: canonicalize signed compares with constant Luc Van Oostenryck
2021-01-26 22:04 ` [PATCH 09/10] cmps: canonicalize SEL(x {<,<=} y, a, b) --> SEL(x {>=,>} y, b, a) Luc Van Oostenryck
2021-01-26 22:04 ` [PATCH 10/10] cmps: canonicalize SEL(x > 0, a, -a) --> SEL(x >= 0, a, -a) Luc Van Oostenryck
2021-04-17 17:16 ` [PATCH 00/10] simplify and canonicalize signed compares Linus Torvalds
2021-04-17 18:20   ` Luc Van Oostenryck

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