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, 6 insertions, 0 deletions

diff --git a/llvm/lib/IR/Function.cpp b/llvm/lib/IR/Function.cpp
index fe44f17d686..33e15262524 100644
--- a/llvm/lib/IR/Function.cpp
+++ b/llvm/lib/IR/Function.cpp
@@ -343,6 +343,12 @@ void Function::removeAttributes(unsigned i, AttributeSet attrs) {
   setAttributes(PAL);
 }
 
+void Function::addDereferenceableAttr(unsigned i, uint64_t Bytes) {
+  AttributeSet PAL = getAttributes();
+  PAL = PAL.addDereferenceableAttr(getContext(), i, Bytes);
+  setAttributes(PAL);
+}
+
 // Maintain the GC name for each function in an on-the-side table. This saves
 // allocating an additional word in Function for programs which do not use GC
 // (i.e., most programs) at the cost of increased overhead for clients which do