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* [gcc/devel/c++-modules] analyzer: fix ICE with negative bit offsets [PR96648]
@ 2020-08-27 18:15 Nathan Sidwell
0 siblings, 0 replies; only message in thread
From: Nathan Sidwell @ 2020-08-27 18:15 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:400abebf48a90d0797718ab7c3864de331e85b70
commit 400abebf48a90d0797718ab7c3864de331e85b70
Author: David Malcolm <dmalcolm@redhat.com>
Date: Mon Aug 17 21:12:35 2020 -0400
analyzer: fix ICE with negative bit offsets [PR96648]
PR analyzer/96648 reports an ICE within get_field_at_bit_offset due
to a negative bit offset, arising due to pointer arithmetic.
This patch replaces an assertion with handling for this case, fixing the
ICE.
gcc/analyzer/ChangeLog:
PR analyzer/96648
* region.cc (get_field_at_bit_offset): Gracefully handle negative
values for bit_offset.
gcc/testsuite/ChangeLog:
PR analyzer/96648
* gcc.dg/analyzer/pr96648.c: New test.
Diff:
---
gcc/analyzer/region.cc | 3 ++-
gcc/testsuite/gcc.dg/analyzer/pr96648.c | 36 +++++++++++++++++++++++++++++++++
2 files changed, 38 insertions(+), 1 deletion(-)
diff --git a/gcc/analyzer/region.cc b/gcc/analyzer/region.cc
index eab1f2771cf..770e2cb849e 100644
--- a/gcc/analyzer/region.cc
+++ b/gcc/analyzer/region.cc
@@ -226,7 +226,8 @@ static tree
get_field_at_bit_offset (tree record_type, bit_offset_t bit_offset)
{
gcc_assert (TREE_CODE (record_type) == RECORD_TYPE);
- gcc_assert (bit_offset >= 0);
+ if (bit_offset < 0)
+ return NULL;
/* Find the first field that has an offset > BIT_OFFSET,
then return the one preceding it.
diff --git a/gcc/testsuite/gcc.dg/analyzer/pr96648.c b/gcc/testsuite/gcc.dg/analyzer/pr96648.c
new file mode 100644
index 00000000000..a6b0c727287
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/analyzer/pr96648.c
@@ -0,0 +1,36 @@
+/* { dg-additional-options "-O1" } */
+
+struct vd {
+ struct vd *rs;
+};
+
+struct fh {
+ struct vd cl;
+};
+
+struct i3 {
+ struct fh *h4;
+};
+
+struct fh *
+gm (void);
+
+void
+j7 (struct vd *);
+
+inline void
+mb (struct vd *e7)
+{
+ j7 (e7->rs);
+}
+
+void
+po (struct i3 *d2)
+{
+ struct i3 *s2;
+
+ d2->h4 = gm ();
+ mb (&d2->h4->cl);
+ s2 = ({ d2 - 1; });
+ po (s2);
+}
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