Tidy up label-exclude and env var docs.
diff --git a/build_tools/bazel/build_core.sh b/build_tools/bazel/build_core.sh
index 15c31c7..1e63328 100755
--- a/build_tools/bazel/build_core.sh
+++ b/build_tools/bazel/build_core.sh
@@ -13,7 +13,7 @@
# Looks at environment variables and uses CI-friendly defaults if they are not
# set.
# IREE_LLVMAOT_DISABLE: Do not run tests that require LLVM-AOT. Default: 0
-# IREE_VULKAN_DISABLE: Do not run tests that require Vulkan. Default: 1
+# IREE_VULKAN_DISABLE: Do not run tests that require Vulkan. Default: 0
# BUILD_TAG_FILTERS: Passed to bazel to filter targets to build.
# See https://docs.bazel.build/versions/master/command-line-reference.html#flag--build_tag_filters)
# Default: "-nokokoro"
diff --git a/build_tools/cmake/test.sh b/build_tools/cmake/test.sh
index bb0c5c5..50d4640 100755
--- a/build_tools/cmake/test.sh
+++ b/build_tools/cmake/test.sh
@@ -18,8 +18,7 @@
# Respect the user setting, but default to as many jobs as we have cores.
export CTEST_PARALLEL_LEVEL=${CTEST_PARALLEL_LEVEL:-$(nproc)}
-# Respect the user setting, but default to turning off the vulkan tests
-# and turning on the llvmaot ones.
+# Respect the user setting, but default to turning on vulkan and llvmaot.
export IREE_VULKAN_DISABLE=${IREE_VULKAN_DISABLE:-0}
export IREE_LLVMAOT_DISABLE=${IREE_LLVMAOT_DISABLE:-0}
# CUDA is off by default.
diff --git a/build_tools/kokoro/gcp_ubuntu/cmake/linux/x86-swiftshader-asan/build.sh b/build_tools/kokoro/gcp_ubuntu/cmake/linux/x86-swiftshader-asan/build.sh
index 0076da6..0577ada 100755
--- a/build_tools/kokoro/gcp_ubuntu/cmake/linux/x86-swiftshader-asan/build.sh
+++ b/build_tools/kokoro/gcp_ubuntu/cmake/linux/x86-swiftshader-asan/build.sh
@@ -120,5 +120,5 @@
echo "Testing with ctest"
ctest --timeout 900 --output-on-failure \
- --label-exclude "^driver=cuda$|^driver=vulkan$" \
+ --label-exclude "${label_exclude_regex}" \
--exclude-regex "${excluded_tests_regex?}"
