diff --git a/llvm/cmake/config-ix.cmake b/llvm/cmake/config-ix.cmake
--- a/llvm/cmake/config-ix.cmake
+++ b/llvm/cmake/config-ix.cmake
@@ -284,9 +284,6 @@
 if( HAVE_SIGNAL_H AND NOT LLVM_USE_SANITIZER MATCHES ".*Address.*" AND NOT APPLE )
   check_symbol_exists(sigaltstack signal.h HAVE_SIGALTSTACK)
 endif()
-set(CMAKE_REQUIRED_DEFINITIONS "-D_LARGEFILE64_SOURCE")
-check_symbol_exists(lseek64 "sys/types.h;unistd.h" HAVE_LSEEK64)
-set(CMAKE_REQUIRED_DEFINITIONS "")
 check_symbol_exists(mallctl malloc_np.h HAVE_MALLCTL)
 check_symbol_exists(mallinfo malloc.h HAVE_MALLINFO)
 check_symbol_exists(mallinfo2 malloc.h HAVE_MALLINFO2)
@@ -340,6 +337,11 @@
 if( LLVM_USING_GLIBC )
   add_compile_definitions(_GNU_SOURCE)
   list(APPEND CMAKE_REQUIRED_DEFINITIONS "-D_GNU_SOURCE")
+# enable 64bit off_t on 32bit systems using glibc
+  if (CMAKE_SIZEOF_VOID_P EQUAL 4)
+    add_compile_definitions(_FILE_OFFSET_BITS=64)
+    list(APPEND CMAKE_REQUIRED_DEFINITIONS "-D_FILE_OFFSET_BITS=64")
+  endif()
 endif()
 
 # This check requires _GNU_SOURCE.
diff --git a/llvm/include/llvm/Config/config.h.cmake b/llvm/include/llvm/Config/config.h.cmake
--- a/llvm/include/llvm/Config/config.h.cmake
+++ b/llvm/include/llvm/Config/config.h.cmake
@@ -128,9 +128,6 @@
 /* Define to 1 if you have the <link.h> header file. */
 #cmakedefine HAVE_LINK_H ${HAVE_LINK_H}
 
-/* Define to 1 if you have the `lseek64' function. */
-#cmakedefine HAVE_LSEEK64 ${HAVE_LSEEK64}
-
 /* Define to 1 if you have the <mach/mach.h> header file. */
 #cmakedefine HAVE_MACH_MACH_H ${HAVE_MACH_MACH_H}
 
diff --git a/llvm/lib/Support/raw_ostream.cpp b/llvm/lib/Support/raw_ostream.cpp
--- a/llvm/lib/Support/raw_ostream.cpp
+++ b/llvm/lib/Support/raw_ostream.cpp
@@ -802,8 +802,6 @@
   flush();
 #ifdef _WIN32
   pos = ::_lseeki64(FD, off, SEEK_SET);
-#elif defined(HAVE_LSEEK64)
-  pos = ::lseek64(FD, off, SEEK_SET);
 #else
   pos = ::lseek(FD, off, SEEK_SET);
 #endif
diff --git a/llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn b/llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn
--- a/llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn
+++ b/llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn
@@ -139,7 +139,6 @@
     values += [
       "HAVE_FUTIMENS=1",
       "HAVE_LINK_H=1",
-      "HAVE_LSEEK64=1",
       "HAVE_MALLINFO=1",
       "HAVE_STRUCT_STAT_ST_MTIM_TV_NSEC=1",
     ]
@@ -147,7 +146,6 @@
     values += [
       "HAVE_FUTIMENS=",
       "HAVE_LINK_H=",
-      "HAVE_LSEEK64=",
       "HAVE_MALLINFO=",
       "HAVE_STRUCT_STAT_ST_MTIM_TV_NSEC=",
     ]
diff --git a/utils/bazel/llvm_configs/config.h.cmake b/utils/bazel/llvm_configs/config.h.cmake
--- a/utils/bazel/llvm_configs/config.h.cmake
+++ b/utils/bazel/llvm_configs/config.h.cmake
@@ -128,9 +128,6 @@
 /* Define to 1 if you have the <link.h> header file. */
 #cmakedefine HAVE_LINK_H ${HAVE_LINK_H}
 
-/* Define to 1 if you have the `lseek64' function. */
-#cmakedefine HAVE_LSEEK64 ${HAVE_LSEEK64}
-
 /* Define to 1 if you have the <mach/mach.h> header file. */
 #cmakedefine HAVE_MACH_MACH_H ${HAVE_MACH_MACH_H}