poor (and wrong) approximation of the actual rules governing when to
build a copy and when it can be elided.
The correct implementation is actually simpler than the
approximation. When we only enumerate constructors as part of
initialization (e.g., for direct initialization or when we're copying
from a class type or one of its derived classes), we don't create a
copy. When we enumerate all conversion functions, we do create a
copy. Before, we created some extra copies and missed some
others. The new test copy-initialization.cpp shows a case where we
missed creating a (required, non-elidable) copy as part of a
user-defined conversion, which resulted in a miscompile. This commit
also fixes PR6757, where the missing copy made us reject well-formed
code in the ternary operator.
This commit also cleans up our handling of copy elision in the case
where we create an extra copy of a temporary object, which became
necessary now that we produce the right copies. The code that seeks to
find the temporary object being copied has moved into
Expr::getTemporaryObject(); it used to have two different
not-quite-the-same implementations, one in Sema and one in CodeGen.
Note that we still do not attempt to perform the named return value
optimization, so we miss copy elisions for return values and throw
expressions.
llvm-svn: 100196
(http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20091214/092780.html)
The instruction fixes were checked and approved by Chris Lattner, but
these testcase fixes are mine; please yell at me if there are any
problems with either.
* PR5050-constructor-conversion.cpp
* array-construction.cpp
* constructor-conversion.cpp
* cast-conversion.cpp
* constructor-default-arg.cpp
* derived-to-base-conv.cpp
* ptr-to-member-function.cpp
* call-arg-zero-temp.cpp
* default-destructor-synthesis.cpp
* global-array-destruction.cpp
* array-operator-delete-call.cpp
* decl-ref-init.cpp
* default-constructor-for-members.cpp
* convert-to-fptr.cpp
* constructor-for-array-members.cpp
* conversion-function.cpp
* objc-read-weak-byref.m
Fixed testcase to reflect call qualifier
llvm-svn: 91640
- This is designed to make it obvious that %clang_cc1 is a "test variable"
which is substituted. It is '%clang_cc1' instead of '%clang -cc1' because it
can be useful to redefine what gets run as 'clang -cc1' (for example, to set
a default target).
llvm-svn: 91446
Richard Smith