Add 'nonnull', a new parameter and return attribute which indicates that the pointer is not null. Instcombine will elide comparisons between these and null. Patch by Luqman Aden!

llvm-svn: 209185

llvm/lib/Bitcode/Reader/BitcodeReader.cpp

@@ -569,6 +569,8 @@ static Attribute::AttrKind GetAttrFromCode(uint64_t Code) {
     return Attribute::NoInline;
   case bitc::ATTR_KIND_NON_LAZY_BIND:
     return Attribute::NonLazyBind;
+  case bitc::ATTR_KIND_NON_NULL:
+    return Attribute::NonNull;
   case bitc::ATTR_KIND_NO_RED_ZONE:
     return Attribute::NoRedZone;
   case bitc::ATTR_KIND_NO_RETURN: