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).
llvm-svn: 179925
diff --git a/llvm/lib/IR/Attributes.cpp b/llvm/lib/IR/Attributes.cpp
index 44fa78e..80968db 100644
--- a/llvm/lib/IR/Attributes.cpp
+++ b/llvm/lib/IR/Attributes.cpp
@@ -195,6 +195,8 @@
return "readnone";
if (hasAttribute(Attribute::ReadOnly))
return "readonly";
+ if (hasAttribute(Attribute::Returned))
+ return "returned";
if (hasAttribute(Attribute::ReturnsTwice))
return "returns_twice";
if (hasAttribute(Attribute::SExt))
@@ -393,6 +395,7 @@
case Attribute::SanitizeThread: return 1ULL << 36;
case Attribute::SanitizeMemory: return 1ULL << 37;
case Attribute::NoBuiltin: return 1ULL << 38;
+ case Attribute::Returned: return 1ULL << 39;
}
llvm_unreachable("Unsupported attribute type");
}