Add low-level option for avoiding float stores from va_start until
soft-float is properly supported.

llvm-svn: 215221
diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
index 36e1e13..085318c 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -39,6 +39,10 @@
 #include "llvm/Target/TargetOptions.h"
 using namespace llvm;
 
+// FIXME: Remove this once soft-float is supported.
+static cl::opt<bool> DisablePPCFloatInVariadic("disable-ppc-float-in-variadic",
+cl::desc("disable saving float registers for va_start on PPC"), cl::Hidden);
+
 static cl::opt<bool> DisablePPCPreinc("disable-ppc-preinc",
 cl::desc("disable preincrement load/store generation on PPC"), cl::Hidden);
 
@@ -2494,7 +2498,9 @@
       PPC::F1, PPC::F2, PPC::F3, PPC::F4, PPC::F5, PPC::F6, PPC::F7,
       PPC::F8
     };
-    const unsigned NumFPArgRegs = array_lengthof(FPArgRegs);
+    unsigned NumFPArgRegs = array_lengthof(FPArgRegs);
+    if (DisablePPCFloatInVariadic)
+      NumFPArgRegs = 0;
 
     FuncInfo->setVarArgsNumGPR(CCInfo.getFirstUnallocated(GPArgRegs,
                                                           NumGPArgRegs));