From: Kyrylo Tkachov <[email protected]>
UBSan instruments signed integral vector arithmetic. However,
TYPE_OVERFLOW_SANITIZED only accepts scalar integral types. Folding can use
the false result to remove a vector operation before UBSan instruments it.
For example:
typedef int v4si __attribute__ ((vector_size (16)));
v4si f (v4si x) { return -(-x); }
Both negations can overflow. The scalar-only predicate lets fold-const reduce
the function to x and remove both diagnostics.
aarch64 -O2 -fsanitize=signed-integer-overflow
-fsanitize-trap=signed-integer-overflow before:
f:
ret
After:
f:
fmov w0, s0
negs w0, w0
bvs .L27
...
neg v31.4s, v0.4s
fmov w0, s31
negs w0, w0
bvs .L27
...
ret
.L27:
brk #1000
Use ANY_INTEGRAL_TYPE_P so the predicate also accepts integral vector types.
The test checks that both vector negations remain for UBSan instrumentation.
Bootstrapped and tested on aarch64-none-linux-gnu and x86_64-pc-linux-gnu.
Ok for trunk?
Thanks,
Kyrill
gcc/ChangeLog:
* tree.h (TYPE_OVERFLOW_SANITIZED): Use ANY_INTEGRAL_TYPE_P.
gcc/testsuite/ChangeLog:
* c-c++-common/ubsan/overflow-vec-3.c: New test.
Signed-off-by: Kyrylo Tkachov <[email protected]>
---
gcc/testsuite/c-c++-common/ubsan/overflow-vec-3.c | 12 ++++++++++++
gcc/tree.h | 2 +-
2 files changed, 13 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/c-c++-common/ubsan/overflow-vec-3.c
diff --git a/gcc/testsuite/c-c++-common/ubsan/overflow-vec-3.c
b/gcc/testsuite/c-c++-common/ubsan/overflow-vec-3.c
new file mode 100644
index 00000000000..56b00e81a76
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/ubsan/overflow-vec-3.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -Wno-psabi -fsanitize=signed-integer-overflow
-fdump-tree-ubsan" } */
+
+typedef int v4si __attribute__ ((vector_size (4 * sizeof (int))));
+
+v4si
+f (v4si x)
+{
+ return -(-x);
+}
+
+/* { dg-final { scan-tree-dump-times "\\.UBSAN_CHECK_SUB" 2 "ubsan" } } */
diff --git a/gcc/tree.h b/gcc/tree.h
index e079082a81a..6e1bea14406 100644
--- a/gcc/tree.h
+++ b/gcc/tree.h
@@ -1005,7 +1005,7 @@ extern void omp_clause_range_check_failed (const_tree,
const char *, int,
/* True if an overflow is to be preserved for sanitization. */
#define TYPE_OVERFLOW_SANITIZED(TYPE) \
- (INTEGRAL_TYPE_P (TYPE) \
+ (ANY_INTEGRAL_TYPE_P (TYPE) \
&& !TYPE_OVERFLOW_WRAPS (TYPE) \
&& (flag_sanitize & SANITIZE_SI_OVERFLOW))
--
2.50.1 (Apple Git-155)
