diff --git a/compiler-rt/lib/builtins/CMakeLists.txt b/compiler-rt/lib/builtins/CMakeLists.txt
--- a/compiler-rt/lib/builtins/CMakeLists.txt
+++ b/compiler-rt/lib/builtins/CMakeLists.txt
@@ -553,11 +553,8 @@
 
 set(powerpc64_SOURCES
   ppc/divtc3.c
-  ppc/fixtfti.c
   ppc/fixtfdi.c
-  ppc/fixunstfti.c
   ppc/fixunstfdi.c
-  ppc/floattitf.c
   ppc/floatditf.c
   ppc/floatunditf.c
   ppc/gcc_qadd.c
@@ -567,6 +564,15 @@
   ppc/multc3.c
   ${GENERIC_SOURCES}
 )
+# These routines require __int128, whic isn't supported on AIX.
+if (NOT ${CMAKE_SYSTEM_NAME} MATCHES "AIX")
+  set(powerpc64_SOURCES
+    ppc/floattitf.c
+    ppc/fixtfti.c
+    ppc/fixunstfti.c
+    ${powerpc64_SOURCES}
+  )
+endif()
 set(powerpc64le_SOURCES ${powerpc64_SOURCES})
 
 set(riscv_SOURCES ${GENERIC_SOURCES} ${GENERIC_TF_SOURCES})