Index: compiler-rt/lib/builtins/CMakeLists.txt
===================================================================
--- compiler-rt/lib/builtins/CMakeLists.txt
+++ compiler-rt/lib/builtins/CMakeLists.txt
@@ -593,6 +593,7 @@
 set(riscv_SOURCES
   riscv/save.S
   riscv/restore.S
+  riscv/restore_tailcall.S
   ${GENERIC_SOURCES}
   ${GENERIC_TF_SOURCES}
 )
Index: compiler-rt/lib/builtins/riscv/restore_tailcall.S
===================================================================
--- /dev/null
+++ compiler-rt/lib/builtins/riscv/restore_tailcall.S
@@ -0,0 +1,92 @@
+//===-- restore_tailcall.S - restore up to 12 callee-save registers -------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// Multiple entry points which restores a variable number of callee-saved
+// registers and then performs a tailcall.
+//
+//===----------------------------------------------------------------------===//
+
+#include "save_restore.h"
+
+  // All of the entry points are in the same section since we rely on many of
+  // them falling through into each other and don't want the linker to
+  // accidentally split them up, garbage collect, or reorder them.
+  .text
+  .align  2
+
+  // These are alternative entry points to the normal __riscv_restore_N
+  // functions, which allow the save-restore mechanism to be used even when
+  // the caller is making a tail call.
+  //
+  // On entry to these functions the target of the tail call is found in
+  // register `t1'. Instead of returning through `ra' like __riscv_restore_N,
+  // these functions do an indirect jump through `t1'.
+
+  .globl  __riscv_restore_tailcall_12
+  .type   __riscv_restore_tailcall_12,@function
+__riscv_restore_tailcall_12:
+  LOAD    s11, (3*STRIDE)(sp)
+  addi    sp, sp, 4*STRIDE
+  // fallthrough into __riscv_restore_tailcall_11/10/9/8
+
+  .globl  __riscv_restore_tailcall_11
+  .type   __riscv_restore_tailcall_11,@function
+  .globl  __riscv_restore_tailcall_10
+  .type   __riscv_restore_tailcall_10,@function
+  .globl  __riscv_restore_tailcall_9
+  .type   __riscv_restore_tailcall_9,@function
+  .globl  __riscv_restore_tailcall_8
+  .type   __riscv_restore_tailcall_8,@function
+__riscv_restore_tailcall_11:
+__riscv_restore_tailcall_10:
+__riscv_restore_tailcall_9:
+__riscv_restore_tailcall_8:
+  LOAD    s10, (0*STRIDE)(sp)
+  LOAD    s9,  (1*STRIDE)(sp)
+  LOAD    s8,  (2*STRIDE)(sp)
+  LOAD    s7,  (3*STRIDE)(sp)
+  addi    sp, sp, 4*STRIDE
+  // fallthrough into __riscv_restore_tailcall_7/6/5/4
+
+  .globl  __riscv_restore_tailcall_7
+  .type   __riscv_restore_tailcall_7,@function
+  .globl  __riscv_restore_tailcall_6
+  .type   __riscv_restore_tailcall_6,@function
+  .globl  __riscv_restore_tailcall_5
+  .type   __riscv_restore_tailcall_5,@function
+  .globl  __riscv_restore_tailcall_4
+  .type   __riscv_restore_tailcall_4,@function
+__riscv_restore_tailcall_7:
+__riscv_restore_tailcall_6:
+__riscv_restore_tailcall_5:
+__riscv_restore_tailcall_4:
+  LOAD    s6,  (0*STRIDE)(sp)
+  LOAD    s5,  (1*STRIDE)(sp)
+  LOAD    s4,  (2*STRIDE)(sp)
+  LOAD    s3,  (3*STRIDE)(sp)
+  addi    sp, sp, 4*STRIDE
+  // fallthrough into __riscv_restore_tailcall_3/2/1/0
+
+  .globl  __riscv_restore_tailcall_3
+  .type   __riscv_restore_tailcall_3,@function
+  .globl  __riscv_restore_tailcall_2
+  .type   __riscv_restore_tailcall_2,@function
+  .globl  __riscv_restore_tailcall_1
+  .type   __riscv_restore_tailcall_1,@function
+  .globl  __riscv_restore_tailcall_0
+  .type   __riscv_restore_tailcall_0,@function
+__riscv_restore_tailcall_3:
+__riscv_restore_tailcall_2:
+__riscv_restore_tailcall_1:
+__riscv_restore_tailcall_0:
+  LOAD    s2,  (0*STRIDE)(sp)
+  LOAD    s1,  (1*STRIDE)(sp)
+  LOAD    s0,  (2*STRIDE)(sp)
+  LOAD    ra,  (3*STRIDE)(sp)
+  addi    sp, sp, 4*STRIDE
+  jr      t1