From a99ec28134c2fd0a21c446a58bf6406b8aa1a580 Mon Sep 17 00:00:00 2001
From: Bill Wendling <isanbard@gmail.com>
Date: Thu, 6 Jan 2011 00:50:34 +0000
Subject: [PATCH] PR8919 - LLVM incorrectly generates "_alloca" as the stack
 probing call. That works only on MinGW32. On 64-bit, the function to call is
 "__chkstk". Patch by KS Sreeram!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122934 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/X86/X86FrameInfo.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lib/Target/X86/X86FrameInfo.cpp b/lib/Target/X86/X86FrameInfo.cpp
index afadb4c9b3d..5a8d9768f84 100644
--- a/lib/Target/X86/X86FrameInfo.cpp
+++ b/lib/Target/X86/X86FrameInfo.cpp
@@ -566,6 +566,8 @@ void X86FrameInfo::emitPrologue(MachineFunction &MF) const {
 
     const char *StackProbeSymbol =
       STI.isTargetWindows() ? "_chkstk" : "_alloca";
+    if (Is64Bit && STI.isTargetCygMing())
+      StackProbeSymbol = "__chkstk";
     unsigned CallOp = Is64Bit ? X86::CALL64pcrel32 : X86::CALLpcrel32;
     if (!isEAXAlive) {
       BuildMI(MBB, MBBI, DL, TII.get(X86::MOV32ri), X86::EAX)