Add some constraints to use of 'returned':
1) Disallow 'returned' on parameter that is also 'sret' (no sensible semantics, as far as I can tell).
2) Conservatively disallow tail calls through 'returned' parameters that also are 'zext' or 'sext' (for consistency with treatment of other zero-extending and sign-extending operations in tail call position detection...can be revised later to handle situations that can be determined to be safe).
This is a new attribute that is not yet used, so there is no impact.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@180118 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/IR/Verifier.cpp b/lib/IR/Verifier.cpp
index 888090d..d106173 100644
--- a/lib/IR/Verifier.cpp
+++ b/lib/IR/Verifier.cpp
@@ -740,6 +740,10 @@
Attrs.hasAttribute(Idx, Attribute::InReg))), "Attributes "
"'byval, nest, and inreg' are incompatible!", V);
+ Assert1(!(Attrs.hasAttribute(Idx, Attribute::StructRet) &&
+ Attrs.hasAttribute(Idx, Attribute::Returned)), "Attributes "
+ "'sret and returned' are incompatible!", V);
+
Assert1(!(Attrs.hasAttribute(Idx, Attribute::ZExt) &&
Attrs.hasAttribute(Idx, Attribute::SExt)), "Attributes "
"'zeroext and signext' are incompatible!", V);