diff --git a/tests/scripts/components-compiler.sh b/tests/scripts/components-compiler.sh
index 74543b1..83fcf9b 100644
--- a/tests/scripts/components-compiler.sh
+++ b/tests/scripts/components-compiler.sh
@@ -73,6 +73,23 @@
     type "$GCC_LATEST" >/dev/null 2>/dev/null
 }
 
+# Prepare for a non-regression for https://github.com/Mbed-TLS/mbedtls/issues/9814 :
+# test with GCC 15 (initially, a snapshot, since GCC 15 isn't released yet
+# at the time of writing).
+# Eventually, $GCC_LATEST will be GCC 15 or above, and we can remove this
+# separate component.
+# For the time being, we don't make $GCC_LATEST be GCC 15 on the CI
+# platform, because that would break branches where #9814 isn'f fixed yet.
+support_test_gcc15_opt () {
+    test -x /usr/local/gcc-15/bin/gcc-15
+}
+component_test_gcc15_opt () {
+    scripts/config.py full
+    # Until https://github.com/Mbed-TLS/mbedtls/issues/9814 is fixed,
+    # disable the new problematic optimization.
+    test_build_opt 'full config' "/usr/local/gcc-15/bin/gcc-15 -fzero-init-padding-bits=unions" -O2
+}
+
 component_test_gcc_earliest_opt () {
     scripts/config.py full
     test_build_opt 'full config' "$GCC_EARLIEST" -O2