diff --git a/llvm/lib/CodeGen/SelectionDAG/StatepointLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/StatepointLowering.cpp
--- a/llvm/lib/CodeGen/SelectionDAG/StatepointLowering.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/StatepointLowering.cpp
@@ -113,7 +113,9 @@
   MachineFrameInfo &MFI = Builder.DAG.getMachineFunction().getFrameInfo();
 
   unsigned SpillSize = ValueType.getStoreSize();
-  assert((SpillSize * 8) == ValueType.getSizeInBits() && "Size not in bytes?");
+  assert((SpillSize * 8) ==
+             (-8u & (7 + ValueType.getSizeInBits())) && // Round up modulo 8.
+         "Size not in bytes?");
 
   // First look for a previously created stack slot which is not in
   // use (accounting for the fact arbitrary slots may already be
@@ -386,7 +388,8 @@
     // (i.e. change the '==' in the assert below to a '>=').
     MachineFrameInfo &MFI = Builder.DAG.getMachineFunction().getFrameInfo();
     assert((MFI.getObjectSize(Index) * 8) ==
-           (int64_t)Incoming.getValueSizeInBits() &&
+               (-8 & (7 + // Round up modulo 8.
+                      (int64_t)Incoming.getValueSizeInBits())) &&
            "Bad spill:  stack slot does not match!");
 
     // Note: Using the alignment of the spill slot (rather than the abi or
diff --git a/llvm/test/CodeGen/X86/statepoint-spill-slot-size-promotion.ll b/llvm/test/CodeGen/X86/statepoint-spill-slot-size-promotion.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/X86/statepoint-spill-slot-size-promotion.ll
@@ -0,0 +1,54 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py then fixed by hand.
+; RUN: llc -verify-machineinstrs < %s | FileCheck %s --check-prefixes=CHECK
+;
+; Test different type sizes of deop bundle operands.
+;
+target datalayout = "e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-pc-win64"
+
+define i1 @test_spill_slot_size(i1 %a1, i2 %a2, i7 %a7, i8 %a8, i9 %a9, i15 %a15, i16 %a16, i32 %a32, i64 %a64, i128 %a128, i32 addrspace(1)* %obj1) gc "statepoint-example" {
+; CHECK-LABEL: test_spill_slot_size:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    pushq %rbx
+; CHECK-NEXT:    .cfi_def_cfa_offset 16
+; CHECK-NEXT:    subq $32, %rsp
+; CHECK-NEXT:    .cfi_def_cfa_offset 48
+; CHECK-NEXT:    .cfi_offset %rbx, -16
+; CHECK-NEXT:    movl %edi, %ebx
+; CHECK-NEXT:    movq {{[0-9]+}}(%rsp), %r10
+; CHECK-NEXT:    movq {{[0-9]+}}(%rsp), %r11
+; CHECK-NEXT:    movl {{[0-9]+}}(%rsp), %eax
+; CHECK-NEXT:    movzwl {{[0-9]+}}(%rsp), %edi
+; CHECK-NEXT:    movw %di, {{[0-9]+}}(%rsp)
+; CHECK-NEXT:    movl %eax, {{[0-9]+}}(%rsp)
+; CHECK-NEXT:    movq %r11, {{[0-9]+}}(%rsp)
+; CHECK-NEXT:    movq %r10, {{[0-9]+}}(%rsp)
+; CHECK-NEXT:    movb %cl, {{[0-9]+}}(%rsp)
+; CHECK-NEXT:    andb $3, %sil
+; CHECK-NEXT:    movb %sil, {{[0-9]+}}(%rsp)
+; CHECK-NEXT:    movl %ebx, %eax
+; CHECK-NEXT:    andl $1, %eax
+; CHECK-NEXT:    movb %al, {{[0-9]+}}(%rsp)
+; CHECK-NEXT:    andb $127, %dl
+; CHECK-NEXT:    movb %dl, {{[0-9]+}}(%rsp)
+; CHECK-NEXT:    andl $511, %r8d # imm = 0x1FF
+; CHECK-NEXT:    movw %r8w, {{[0-9]+}}(%rsp)
+; CHECK-NEXT:    andl $32767, %r9d # imm = 0x7FFF
+; CHECK-NEXT:    movw %r9w, {{[0-9]+}}(%rsp)
+; CHECK-NEXT:    movabsq $140727162896504, %rax # imm = 0x7FFD988E0078
+; CHECK-NEXT:    callq *%rax
+; CHECK-NEXT:  .Ltmp0:
+; CHECK-NEXT:    movl %ebx, %eax
+; CHECK-NEXT:    addq $32, %rsp
+; CHECK-NEXT:    .cfi_def_cfa_offset 16
+; CHECK-NEXT:    popq %rbx
+; CHECK-NEXT:    .cfi_def_cfa_offset 8
+; CHECK-NEXT:    retq
+
+entry:
+  %safepoint_token = call token (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* inttoptr (i64 140727162896504 to void ()*), i32 0, i32 0, i32 0, i32 0)
+      [ "deopt"(i1 %a1, i2 %a2, i7 %a7, i8 %a8, i9 %a9, i15 %a15, i16 %a16, i32 %a32, i64 %a64, i128 %a128, i32 addrspace(1)* %obj1) ]
+  ret i1 %a1
+}
+
+declare token @llvm.experimental.gc.statepoint.p0f_isVoidf(i64, i32, void ()*, i32, i32, ...)