* [PATCH] tree-optimization/108306 - Correctly detect shifts out of range
@ 2023-01-23 23:21 Andrew MacLeod
2023-01-24 8:57 ` Richard Biener
0 siblings, 1 reply; 2+ messages in thread
From: Andrew MacLeod @ 2023-01-23 23:21 UTC (permalink / raw)
To: gcc-patches; +Cc: hernandez, aldy
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get_shift_range was incorrectly communicating that it couldn't calculate
a range when the shift value was out of range.
Fix this and always return a range of [0, 0] instead of varying when the
shift value is out of range.
Bootstraps with no regressions on x86_64-pc-linux-gnu. OK for trunk?
Andrew
[-- Attachment #2: 0003-Correctly-detect-shifts-out-of-range.patch --]
[-- Type: text/x-patch, Size: 2239 bytes --]
From 5500762bacffd7b45a0bfa8f89333e955734820f Mon Sep 17 00:00:00 2001
From: Andrew MacLeod <amacleod@redhat.com>
Date: Mon, 16 Jan 2023 15:02:51 -0500
Subject: [PATCH 3/3] Correctly detect shifts out of range
get_shift_range was incorrectly communicating that it couldn't calculate
a range when the shift values was always out fo range. Fix this and
alwasy return [0, 0] when the shift value is always out of range.
PR tree-optimization/108306
gcc/
* range-op.cc (operator_lshift::fold_range): Return [0, 0] not
varying for shifts that are always out of void range.
(operator_rshift::fold_range): Return [0, 0] not
varying for shifts that are always out of void range.
gcc/testsuite/
* gcc.dg/pr108306.c: New.
---
gcc/range-op.cc | 4 ++--
gcc/testsuite/gcc.dg/pr108306.c | 29 +++++++++++++++++++++++++++++
2 files changed, 31 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/pr108306.c
diff --git a/gcc/range-op.cc b/gcc/range-op.cc
index ec75e07bc8a..6e5754e9130 100644
--- a/gcc/range-op.cc
+++ b/gcc/range-op.cc
@@ -2166,7 +2166,7 @@ operator_lshift::fold_range (irange &r, tree type,
if (op2.undefined_p ())
r.set_undefined ();
else
- r.set_varying (type);
+ r.set_zero (type);
return true;
}
@@ -2440,7 +2440,7 @@ operator_rshift::fold_range (irange &r, tree type,
if (op2.undefined_p ())
r.set_undefined ();
else
- r.set_varying (type);
+ r.set_zero (type);
return true;
}
diff --git a/gcc/testsuite/gcc.dg/pr108306.c b/gcc/testsuite/gcc.dg/pr108306.c
new file mode 100644
index 00000000000..1044c646de7
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr108306.c
@@ -0,0 +1,29 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fno-strict-overflow -fsanitize=shift -Warray-bounds" } */
+
+enum psi_task_count {
+ NR_IOWAIT,
+ NR_PSI_TASK_COUNTS = 4,
+};
+
+unsigned int tasks[NR_PSI_TASK_COUNTS];
+
+static void psi_group_change(unsigned int set)
+{
+ unsigned int t;
+ unsigned int state_mask = 0;
+
+ for (t = 0; set; set &= ~(1 << t), t++)
+ if (set & (1 << t))
+ tasks[t]++;
+}
+
+void psi_task_switch(int sleep)
+{
+ int set = 0;
+
+ if (sleep)
+ set |= (1 << NR_IOWAIT);
+
+ psi_group_change(set);
+}
--
2.39.0
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] tree-optimization/108306 - Correctly detect shifts out of range
2023-01-23 23:21 [PATCH] tree-optimization/108306 - Correctly detect shifts out of range Andrew MacLeod
@ 2023-01-24 8:57 ` Richard Biener
0 siblings, 0 replies; 2+ messages in thread
From: Richard Biener @ 2023-01-24 8:57 UTC (permalink / raw)
To: Andrew MacLeod; +Cc: gcc-patches, hernandez, aldy
On Tue, Jan 24, 2023 at 12:22 AM Andrew MacLeod via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> get_shift_range was incorrectly communicating that it couldn't calculate
> a range when the shift value was out of range.
>
> Fix this and always return a range of [0, 0] instead of varying when the
> shift value is out of range.
>
> Bootstraps with no regressions on x86_64-pc-linux-gnu. OK for trunk?
OK.
> Andrew
^ permalink raw reply [flat|nested] 2+ messages in thread
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