From: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
To: linux-sparse@vger.kernel.org
Cc: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Subject: [PATCH 05/10] cmps: simplify signed compares with SMIN or SMAX
Date: Tue, 26 Jan 2021 23:04:27 +0100 [thread overview]
Message-ID: <20210126220432.58265-6-luc.vanoostenryck@gmail.com> (raw)
In-Reply-To: <20210126220432.58265-1-luc.vanoostenryck@gmail.com>
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 --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
--
2.30.0
next prev parent reply other threads:[~2021-01-27 3:46 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 ` Luc Van Oostenryck [this message]
2021-01-26 22:04 ` [PATCH 06/10] cmps: canonicalize signed compares with SMIN/SMAX Luc Van Oostenryck
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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