Next step in Mips16 prologue/epilogue cleanup.

Save S2(reg 18) only when we are calling floating point stubs that
have a return value of float or complex. Some more work to make this
better but this is the first step.

llvm-svn: 196921

1 files changed, 3 insertions, 0 deletions

diff --git a/llvm/lib/Target/Mips/MipsRegisterInfo.cpp b/llvm/lib/Target/Mips/MipsRegisterInfo.cpp
index 3105b020845..65b1f8cf2d1 100644
--- a/llvm/lib/Target/Mips/MipsRegisterInfo.cpp
+++ b/llvm/lib/Target/Mips/MipsRegisterInfo.cpp
@@ -27,6 +27,7 @@
 #include "llvm/CodeGen/ValueTypes.h"
 #include "llvm/DebugInfo.h"
 #include "llvm/IR/Constants.h"
+#include "llvm/IR/Function.h"
 #include "llvm/IR/Type.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
@@ -183,6 +184,8 @@ getReservedRegs(const MachineFunction &MF) const {
     Reserved.set(Mips::RA_64);
     Reserved.set(Mips::T0);
     Reserved.set(Mips::T1);
+    if (MF.getFunction()->hasFnAttribute("saveS2"))
+      Reserved.set(Mips::S2);
   }
 
   // Reserve GP if small section is used.