Add limit for scalar replacment when fuzzing (#4843)
The fuzzer cretes code with very large array, and scalar replacement
times out. Adding a limit on the size of the composites that will be
split when fuzzing.
Fixes https://crbug.com/oss-fuzz/48630
diff --git a/source/opt/scalar_replacement_pass.h b/source/opt/scalar_replacement_pass.h
index 3d1377b..6a66dfb 100644
--- a/source/opt/scalar_replacement_pass.h
+++ b/source/opt/scalar_replacement_pass.h
@@ -42,6 +42,16 @@
name_, sizeof(name_), "scalar-replacement=%u", max_num_elements_);
assert(size_t(num_to_write) < sizeof(name_));
(void)num_to_write; // Mark as unused
+
+#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
+ // ClusterFuzz/OSS-Fuzz is likely to yield examples with very large arrays.
+ // This can cause timeouts and memouts during fuzzing that
+ // are not classed as bugs. To avoid this noise, we set the
+ // max_num_elements_ to a smaller value for fuzzing.
+ max_num_elements_ =
+ (max_num_elements_ > 0 && max_num_elements_ < 100 ? max_num_elements_
+ : 100);
+#endif
}
const char* name() const override { return name_; }
