There are a couple of -Wconversion warnings in the foreign benchmarks:

./test/micro/org/openjdk/bench/java/lang/foreign/libQSortJNI.c: In function ‘Java_org_openjdk_bench_java_lang_foreign_QSort_jni_1qsort_1optimized’:
./test/micro/org/openjdk/bench/java/lang/foreign/libQSortJNI.c:59:17: warning: conversion to ‘size_t’ {aka ‘long unsigned int’} from ‘jsize’ {aka ‘int’} may change the sign of the result [-Wsign-conversion]
   59 | qsort(ints, length, sizeof(jint), &comparator);
      | ^~~~~~
./test/micro/org/openjdk/bench/java/lang/foreign/libQSortJNI.c: In function ‘Java_org_openjdk_bench_java_lang_foreign_QSort_jni_1qsort_1naive’:
./test/micro/org/openjdk/bench/java/lang/foreign/libQSortJNI.c:87:17: warning: conversion to ‘size_t’ {aka ‘long unsigned int’} from ‘jsize’ {aka ‘int’} may change the sign of the result [-Wsign-conversion]
   87 | qsort(carr, length, sizeof(jint), java_cmp);
      |