Add CodeGen support for functions that always return arguments via a new parameter attribute 'returned', which is taken advantage of in target-independent tail call opportunity detection and in ARM call lowering (when placed on an integral first parameter).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179925 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 6 insertions, 0 deletions

diff --git a/lib/Target/ARM/ARMBaseRegisterInfo.cpp b/lib/Target/ARM/ARMBaseRegisterInfo.cpp
index b6b27f849a..b0d34a76b0 100644
--- a/lib/Target/ARM/ARMBaseRegisterInfo.cpp
+++ b/lib/Target/ARM/ARMBaseRegisterInfo.cpp
@@ -75,6 +75,12 @@ ARMBaseRegisterInfo::getCallPreservedMask(CallingConv::ID) const {
 }
 
 const uint32_t*
+ARMBaseRegisterInfo::getThisReturnPreservedMask(CallingConv::ID) const {
+  return (STI.isTargetIOS() && !STI.isAAPCS_ABI())
+    ? CSR_iOS_ThisReturn_RegMask : CSR_AAPCS_ThisReturn_RegMask;
+}
+
+const uint32_t*
 ARMBaseRegisterInfo::getNoPreservedMask() const {
   return CSR_NoRegs_RegMask;
 }