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
@@ -330,7 +330,6 @@
     set(x86_64_SOURCES
       ${x86_64_SOURCES}
       x86_64/chkstk.S
-      x86_64/chkstk2.S
     )
   endif()
 
@@ -363,7 +362,6 @@
   if (WIN32)
     set(i386_SOURCES
       ${i386_SOURCES}
-      i386/chkstk.S
       i386/chkstk2.S
     )
   endif()
diff --git a/compiler-rt/lib/builtins/i386/chkstk.S b/compiler-rt/lib/builtins/i386/chkstk.S
deleted file mode 100644
--- a/compiler-rt/lib/builtins/i386/chkstk.S
+++ /dev/null
@@ -1,35 +0,0 @@
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-
-#include "../assembly.h"
-
-// _chkstk routine
-// This routine is windows specific
-// http://msdn.microsoft.com/en-us/library/ms648426.aspx
-
-#ifdef __i386__
-
-.text
-.balign 4
-DEFINE_COMPILERRT_FUNCTION(__chkstk_ms)
-        push   %ecx
-        push   %eax
-        cmp    $0x1000,%eax
-        lea    12(%esp),%ecx
-        jb     1f
-2:
-        sub    $0x1000,%ecx
-        test   %ecx,(%ecx)
-        sub    $0x1000,%eax
-        cmp    $0x1000,%eax
-        ja     2b
-1:
-        sub    %eax,%ecx
-        test   %ecx,(%ecx)
-        pop    %eax
-        pop    %ecx
-        ret
-END_COMPILERRT_FUNCTION(__chkstk_ms)
-
-#endif // __i386__
diff --git a/compiler-rt/lib/builtins/i386/chkstk2.S b/compiler-rt/lib/builtins/i386/chkstk2.S
--- a/compiler-rt/lib/builtins/i386/chkstk2.S
+++ b/compiler-rt/lib/builtins/i386/chkstk2.S
@@ -14,7 +14,7 @@
 .text
 .balign 4
 DEFINE_COMPILERRT_FUNCTION(_alloca) // _chkstk and _alloca are the same function
-DEFINE_COMPILERRT_FUNCTION(__chkstk)
+DEFINE_COMPILERRT_FUNCTION(_chkstk)
         push   %ecx
         cmp    $0x1000,%eax
         lea    8(%esp),%ecx     // esp before calling this routine -> ecx
@@ -35,7 +35,7 @@
         push   (%eax)           // push return address onto the stack
         sub    %esp,%eax        // restore the original value in eax
         ret
-END_COMPILERRT_FUNCTION(__chkstk)
+END_COMPILERRT_FUNCTION(_chkstk)
 END_COMPILERRT_FUNCTION(_alloca)
 
 #endif // __i386__
diff --git a/compiler-rt/lib/builtins/x86_64/chkstk.S b/compiler-rt/lib/builtins/x86_64/chkstk.S
--- a/compiler-rt/lib/builtins/x86_64/chkstk.S
+++ b/compiler-rt/lib/builtins/x86_64/chkstk.S
@@ -18,6 +18,7 @@
 .text
 .balign 4
 DEFINE_COMPILERRT_FUNCTION(___chkstk_ms)
+DEFINE_COMPILERRT_FUNCTION(__chkstk)
         push   %rcx
         push   %rax
         cmp    $0x1000,%rax
@@ -35,6 +36,7 @@
         pop    %rax
         pop    %rcx
         ret
+END_COMPILERRT_FUNCTION(__chkstk)
 END_COMPILERRT_FUNCTION(___chkstk_ms)
 
 #endif // __x86_64__
diff --git a/compiler-rt/lib/builtins/x86_64/chkstk2.S b/compiler-rt/lib/builtins/x86_64/chkstk2.S
deleted file mode 100644
--- a/compiler-rt/lib/builtins/x86_64/chkstk2.S
+++ /dev/null
@@ -1,43 +0,0 @@
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-
-#include "../assembly.h"
-
-#ifdef __x86_64__
-
-// _chkstk (_alloca) routine - probe stack between %rsp and (%rsp-%rax) in 4k increments,
-// then decrement %rsp by %rax.  Preserves all registers except %rsp and flags.
-// This routine is windows specific
-// http://msdn.microsoft.com/en-us/library/ms648426.aspx
-
-.text
-.balign 4
-DEFINE_COMPILERRT_FUNCTION(__alloca)
-        mov    %rcx,%rax        // x64 _alloca is a normal function with parameter in rcx
-        // fallthrough
-DEFINE_COMPILERRT_FUNCTION(___chkstk)
-        push   %rcx
-        cmp    $0x1000,%rax
-        lea    16(%rsp),%rcx     // rsp before calling this routine -> rcx
-        jb     1f
-2:
-        sub    $0x1000,%rcx
-        test   %rcx,(%rcx)
-        sub    $0x1000,%rax
-        cmp    $0x1000,%rax
-        ja     2b
-1:
-        sub    %rax,%rcx
-        test   %rcx,(%rcx)
-
-        lea    8(%rsp),%rax     // load pointer to the return address into rax
-        mov    %rcx,%rsp        // install the new top of stack pointer into rsp
-        mov    -8(%rax),%rcx    // restore rcx
-        push   (%rax)           // push return address onto the stack
-        sub    %rsp,%rax        // restore the original value in rax
-        ret
-END_COMPILERRT_FUNCTION(___chkstk)
-END_COMPILERRT_FUNCTION(__alloca)
-
-#endif // __x86_64__