diff --git a/llvm/lib/Target/X86/X86FrameLowering.cpp b/llvm/lib/Target/X86/X86FrameLowering.cpp
--- a/llvm/lib/Target/X86/X86FrameLowering.cpp
+++ b/llvm/lib/Target/X86/X86FrameLowering.cpp
@@ -1261,7 +1261,7 @@
     if (Is64Bit) {
       // Handle the 64-bit Windows ABI case where we need to call __chkstk.
       // Function prologue is responsible for adjusting the stack pointer.
-      int Alloc = isEAXAlive ? NumBytes - 8 : NumBytes;
+      int64_t Alloc = isEAXAlive ? NumBytes - 8 : NumBytes;
       if (isUInt<32>(Alloc)) {
         BuildMI(MBB, MBBI, DL, TII.get(X86::MOV32ri), X86::EAX)
             .addImm(Alloc)
diff --git a/llvm/test/CodeGen/X86/win64-stackprobe-overflow.ll b/llvm/test/CodeGen/X86/win64-stackprobe-overflow.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/X86/win64-stackprobe-overflow.ll
@@ -0,0 +1,14 @@
+; RUN: llc < %s -mtriple=x86_64-windows-gnu | FileCheck %s
+
+define void @foo() unnamed_addr #0 {
+start:
+  %b = alloca i64, align 8
+  %c = alloca [4294967295 x i8], align 1
+  ret void
+}
+
+attributes #0 = { nonlazybind uwtable "probe-stack"="probe_stack" "target-cpu"="x86-64" }
+
+; CHECK-LABEL: foo:
+; CHECK: movabsq $4294967304, %rax
+; CHECK-NEXT: callq probe_stack