Index: lib/Target/AArch64/AArch64ISelLowering.cpp
===================================================================
--- lib/Target/AArch64/AArch64ISelLowering.cpp
+++ lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -2889,9 +2889,11 @@
   unsigned GPRSaveSize = 8 * (NumGPRArgRegs - FirstVariadicGPR);
   int GPRIdx = 0;
   if (GPRSaveSize != 0) {
-    if (IsWin64)
+    if (IsWin64) {
       GPRIdx = MFI.CreateFixedObject(GPRSaveSize, -(int)GPRSaveSize, false);
-    else
+      if (GPRSaveSize & 15)
+        MFI.CreateFixedObject(8, -(int)alignTo(GPRSaveSize, 16), false);
+    } else
       GPRIdx = MFI.CreateStackObject(GPRSaveSize, 8, false);
 
     SDValue FIN = DAG.getFrameIndex(GPRIdx, PtrVT);
Index: test/CodeGen/AArch64/aarch64_win64cc_vararg.ll
===================================================================
--- test/CodeGen/AArch64/aarch64_win64cc_vararg.ll
+++ test/CodeGen/AArch64/aarch64_win64cc_vararg.ll
@@ -59,10 +59,12 @@
 }
 
 ; CHECK-LABEL: f7:
-; CHECK: sub     sp, sp, #16
-; CHECK: add     x8, sp, #8
-; CHECK: add     x0, sp, #8
-; CHECK: stp     x8, x7, [sp], #16
+; CHECK: sub     sp, sp, #32
+; CHECK: add     x8, sp, #24
+; CHECK: str     x7, [sp, #24]
+; CHECK: add     x0, sp, #24
+; CHECK: str     x8, [sp, #8]
+; CHECK: add     sp, sp, #32
 ; CHECK: ret
 define win64cc i8* @f7(i64 %a0, i64 %a1, i64 %a2, i64 %a3, i64 %a4, i64 %a5, i64 %a6, ...) nounwind {
 entry:
Index: test/CodeGen/AArch64/win64_vararg.ll
===================================================================
--- test/CodeGen/AArch64/win64_vararg.ll
+++ test/CodeGen/AArch64/win64_vararg.ll
@@ -59,10 +59,12 @@
 }
 
 ; CHECK-LABEL: f7:
-; CHECK: sub     sp, sp, #16
-; CHECK: add     x8, sp, #8
-; CHECK: add     x0, sp, #8
-; CHECK: stp     x8, x7, [sp], #16
+; CHECK: sub     sp, sp, #32
+; CHECK: add     x8, sp, #24
+; CHECK: str     x7, [sp, #24]
+; CHECK: add     x0, sp, #24
+; CHECK: str     x8, [sp, #8]
+; CHECK: add     sp, sp, #32
 ; CHECK: ret
 define i8* @f7(i64 %a0, i64 %a1, i64 %a2, i64 %a3, i64 %a4, i64 %a5, i64 %a6, ...) nounwind {
 entry:
@@ -79,9 +81,8 @@
 ; CHECK: stp     x6, x7, [sp, #64]
 ; CHECK: stp     x4, x5, [sp, #48]
 ; CHECK: stp     x2, x3, [sp, #32]
-; CHECK: stp     x8, x1, [sp, #16]
-; CHECK: str     x8, [sp, #8]
-; CHECK: add     sp, sp, #80
+; CHECK: str     x1, [sp, #24]
+; CHECK: stp     x8, x8, [sp], #80
 ; CHECK: ret
 define void @copy1(i64 %a0, ...) nounwind {
 entry: