diff --git a/llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp b/llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp
--- a/llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp
+++ b/llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp
@@ -1669,7 +1669,7 @@
 
   // Emit the Fake Stack Object
   const MachineFrameInfo &MFI = MF.getFrameInfo();
-  int NumBytes = (int) MFI.getStackSize();
+  int64_t NumBytes = MFI.getStackSize();
   if (NumBytes) {
     O << "\t.local .align " << MFI.getMaxAlign().value() << " .b8 \t"
       << DEPOTNAME << getFunctionNumber() << "[" << NumBytes << "];\n";
diff --git a/llvm/test/CodeGen/NVPTX/local-variable-big.ll b/llvm/test/CodeGen/NVPTX/local-variable-big.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/NVPTX/local-variable-big.ll
@@ -0,0 +1,18 @@
+; RUN: llc < %s -march=nvptx | FileCheck %s
+; RUN: llc < %s -march=nvptx64 | FileCheck %s
+; RUN: %if ptxas %{ llc < %s -march=nvptx | %ptxas-verify %}
+; RUN: %if ptxas %{ llc < %s -march=nvptx64 | %ptxas-verify %}
+
+; Make sure there is no integer overflow in the compiler when large
+; local arrays are used.
+;
+; CHECK: .local .align 1 .b8 	__local_depot0[4831838208];
+;
+define i32 @large_data() {
+  %arr = alloca [4831838208 x i8]
+  %p = getelementptr inbounds [4831838208 x i8], [4831838208 x i8]* %arr, i64 0, i64 0
+  %call = call i32 @use(ptr %p)
+  ret i32 %call
+}
+
+declare i32 @use(ptr %p)