================
@@ -293,6 +293,40 @@ To silence reports from unsigned integer overflow, you can
set
``-fsanitize-recover=unsigned-integer-overflow``, is particularly useful for
providing fuzzing signal without blowing up logs.
+Disabling instrumentation for common overflow patterns
+------------------------------------------------------
+
+There are certain overflow-dependent or overflow-prone code patterns which
+produce a lot of noise for integer overflow/truncation sanitizers. To disable
+instrumentation for these common patterns one should use
+``-fsanitize-overflow-pattern-exclusion=``.
+
+Currently, this option supports three pervasive overflow-dependent code idioms:
+
+.. code-block:: c++
+
+ /// -fsanitize-overflow-pattern-exclusion=negated-unsigned-const
+ unsigned long foo = -1UL; // No longer causes a negation overflow warning
+ unsigned long bar = -2UL; // and so on...
+
+.. code-block:: c++
+
+ /// -fsanitize-overflow-pattern-exclusion=post-decr-while
+ unsigned char count = 16;
+ while (count--) { /* ... */ } // No longer causes
unsigned-integer-overflow sanitizer to trip
+
+.. code-block:: c++
+
+ /// -fsanitize-overflow-pattern-exclusion=add-overflow-test
+ if (base + offset < base) { /* ... */ } // The pattern of `a + b < a`, and
other re-orderings,
+ // won't be instrumented (same for
signed types)
+
+Negated unsigned constants, post-decrements in a while loop condition and
----------------
bwendling wrote:
This first line could go to the first paragraph?
https://github.com/llvm/llvm-project/pull/100272
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