diff --git a/clang/test/Driver/arm-float-abi-lto.c b/clang/test/Driver/arm-float-abi-lto.c
--- a/clang/test/Driver/arm-float-abi-lto.c
+++ b/clang/test/Driver/arm-float-abi-lto.c
@@ -1,5 +1,3 @@
-// FIXME: Produces a segmentation fault on AIX after the introduction of opaque pointers (D125847). 
-// UNSUPPORTED: system-aix
 // REQUIRES: arm-registered-target
 
 // RUN: %clang --target=arm-none-eabi -mcpu=cortex-m33 -mfloat-abi=hard -O1 %s -S -o - -emit-llvm -DCALL_LIB -DDEFINE_LIB | FileCheck %s
diff --git a/clang/test/Index/lit.local.cfg b/clang/test/Index/lit.local.cfg
deleted file mode 100644
--- a/clang/test/Index/lit.local.cfg
+++ /dev/null
@@ -1,12 +0,0 @@
-import platform
-
-# Some tests perform deep recursion, which requires a larger pthread stack size
-# than the relatively low default of 192 KiB for 64-bit processes on AIX. The
-# `AIXTHREAD_STK` environment variable provides a non-intrusive way to request
-# a larger pthread stack size for the tests. Various applications and runtime
-# libraries on AIX use a default pthread stack size of 4 MiB, so we will use
-# that as a default value here.
-if 'AIXTHREAD_STK' in os.environ:
-    config.environment['AIXTHREAD_STK'] = os.environ['AIXTHREAD_STK']
-elif platform.system() == 'AIX':
-    config.environment['AIXTHREAD_STK'] = '4194304'
diff --git a/clang/test/lit.cfg.py b/clang/test/lit.cfg.py
--- a/clang/test/lit.cfg.py
+++ b/clang/test/lit.cfg.py
@@ -264,3 +264,13 @@
                       '/ASTMerge/anonymous-fields', '/ASTMerge/injected-class-name-decl'):
         exclude_unsupported_files_for_aix(config.test_source_root + directory)
 
+# Some tests perform deep recursion, which requires a larger pthread stack size
+# than the relatively low default of 192 KiB for 64-bit processes on AIX. The
+# `AIXTHREAD_STK` environment variable provides a non-intrusive way to request
+# a larger pthread stack size for the tests. Various applications and runtime
+# libraries on AIX use a default pthread stack size of 4 MiB, so we will use
+# that as a default value here.
+if 'AIXTHREAD_STK' in os.environ:
+    config.environment['AIXTHREAD_STK'] = os.environ['AIXTHREAD_STK']
+elif platform.system() == 'AIX':
+    config.environment['AIXTHREAD_STK'] = '4194304'