Implement Red Zone utilization on x86-64. This is currently
disabled by default; I'll enable it when I hook it up with
the llvm-gcc flag which controls it.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@63056 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/TargetMachine.cpp b/lib/Target/TargetMachine.cpp
index a1d6fa7..fd577c7 100644
--- a/lib/Target/TargetMachine.cpp
+++ b/lib/Target/TargetMachine.cpp
@@ -40,6 +40,7 @@
   bool VerboseAsm;
   bool DisableJumpTables;
   bool StrongPHIElim;
+  bool DisableRedZone;
 }
 
 static cl::opt<bool, true> PrintCode("print-machineinstrs",
@@ -164,6 +165,12 @@
            cl::location(StrongPHIElim),
            cl::init(false));
 
+static cl::opt<bool, true>
+DisableRedZoneOption("disable-red-zone",
+           cl::desc("Do not emit code that uses the red zone."),
+           cl::location(DisableRedZone),
+           cl::init(true));
+
 //---------------------------------------------------------------------------
 // TargetMachine Class
 //