Index: bolt/lib/Core/Exceptions.cpp
===================================================================
--- bolt/lib/Core/Exceptions.cpp
+++ bolt/lib/Core/Exceptions.cpp
@@ -626,11 +626,13 @@
         errs() << "BOLT-WARNING: DW_CFA_MIPS_advance_loc unimplemented\n";
       return false;
     case DW_CFA_GNU_window_save:
+      Function.addCFIInstruction(
+          Offset, MCCFIInstruction::createNegateRAState(nullptr));
+      break;
     case DW_CFA_lo_user:
     case DW_CFA_hi_user:
       if (opts::Verbosity >= 1) {
-        errs() << "BOLT-WARNING: DW_CFA_GNU_* and DW_CFA_*_user "
-                  "unimplemented\n";
+        errs() << "BOLT-WARNING: DW_CFA_*_user unimplemented\n";
       }
       return false;
     default:
Index: bolt/test/AArch64/dw_cfa_gnu_window_save.cc
===================================================================
--- /dev/null
+++ bolt/test/AArch64/dw_cfa_gnu_window_save.cc
@@ -0,0 +1,10 @@
+// RUN: %clang %cflags -O2 -Wl,-q  %s -o %t.exe
+// RUN: llvm-bolt %t.exe -o %t.bolt 2>&1 | FileCheck %s
+
+// CHECK-NOT: paciasp
+// CHECK-NOT: autiasp
+// CHECK-NOT: ERROR: unable to fill CFI.
+
+int main(int argc, char **argv) {
+  return 0;
+}