InstCombine: propagate deref via new addDereferenceableAttr

The "dereferenceable" attribute cannot be added via .addAttribute(),
since it also expects a size in bytes. AttrBuilder#addAttribute or
AttributeSet#addAttribute is wrapped by classes Function, InvokeInst,
and CallInst. Add corresponding wrappers to
AttrBuilder#addDereferenceableAttr.

Having done this, propagate the dereferenceable attribute via
gc.relocate, adding a test to exercise it. Note that -datalayout is
required during execution over and above -instcombine, because
InstCombine only optionally requires DataLayoutPass.

Differential Revision: http://reviews.llvm.org/D7510

llvm-svn: 229265

1 files changed, 7 insertions, 0 deletions

diff --git a/llvm/lib/IR/Attributes.cpp b/llvm/lib/IR/Attributes.cpp
index 04545ea919a..daac6b5f639 100644
--- a/llvm/lib/IR/Attributes.cpp
+++ b/llvm/lib/IR/Attributes.cpp
@@ -835,6 +835,13 @@ AttributeSet AttributeSet::removeAttributes(LLVMContext &C, unsigned Index,
   return get(C, AttrSet);
 }
 
+AttributeSet AttributeSet::addDereferenceableAttr(LLVMContext &C, unsigned Index,
+                                                  uint64_t Bytes) const {
+  llvm::AttrBuilder B;
+  B.addDereferenceableAttr(Bytes);
+  return addAttributes(C, Index, AttributeSet::get(C, Index, B));
+}
+
 //===----------------------------------------------------------------------===//
 // AttributeSet Accessor Methods
 //===----------------------------------------------------------------------===//