[CodeGen] Do not construct complete LValue base info in trivial cases

Besides obvious code simplification, avoiding explicit creation
of LValueBaseInfo objects makes it easier to make TBAA
information to be part of such objects.

This is part of D38126 reworked to be a separate patch to
simplify review.

Differential Revision: https://reviews.llvm.org/D38695

llvm-svn: 315289
diff --git a/clang/lib/CodeGen/CGBlocks.cpp b/clang/lib/CodeGen/CGBlocks.cpp
index 6f8f356..c4c5541 100644
--- a/clang/lib/CodeGen/CGBlocks.cpp
+++ b/clang/lib/CodeGen/CGBlocks.cpp
@@ -986,9 +986,8 @@
       // FIXME: Pass a specific location for the expr init so that the store is
       // attributed to a reasonable location - otherwise it may be attributed to
       // locations of subexpressions in the initialization.
-      LValueBaseInfo BaseInfo(AlignmentSource::Decl, false);
       EmitExprAsInit(&l2r, &BlockFieldPseudoVar,
-                     MakeAddrLValue(blockField, type, BaseInfo),
+                     MakeAddrLValue(blockField, type, AlignmentSource::Decl),
                      /*captured by init*/ false);
     }