llvm/clang/test/PCH/cxx-dependent-sized-ext-vector.cpp
Luboš Luňák a45f713c67 add option to instantiate templates already in the PCH
Add -fpch-instantiate-templates which makes template instantiations be
performed already in the PCH instead of it being done in every single
file that uses the PCH (but every single file will still do it as well
in order to handle its own instantiations). I can see 20-30% build
time saved with the few tests I've tried.

The change may reorder compiler output and also generated code, but
should be generally safe and produce functionally identical code.
There are some rare cases that do not compile with it,
such as test/PCH/pch-instantiate-templates-forward-decl.cpp. If
template instantiation bailed out instead of reporting the error,
these instantiations could even be postponed, which would make them
work.

Enable this by default for clang-cl. MSVC creates PCHs by compiling
them using an empty .cpp file, which means templates are instantiated
while building the PCH and so the .h needs to be self-contained,
making test/PCH/pch-instantiate-templates-forward-decl.cpp to fail
with MSVC anyway. So the option being enabled for clang-cl matches this.

Differential Revision: https://reviews.llvm.org/D69585
2020-06-21 17:05:52 +02:00

22 lines
566 B
C++

// RUN: %clang_cc1 -std=c++11 -emit-pch %s -o %t
// RUN: %clang_cc1 -std=c++11 -include-pch %t -verify %s
// RUN: %clang_cc1 -std=c++11 -emit-pch -fpch-instantiate-templates %s -o %t
// RUN: %clang_cc1 -std=c++11 -include-pch %t -verify %s
#ifndef HEADER_INCLUDED
#define HEADER_INCLUDED
template<typename T, int N>
using vec = T __attribute__((ext_vector_type(N)));
#else
void test() {
vec<float, 2> a; // expected-error@-5 {{zero vector size}}
vec<float, 0> b; // expected-note {{in instantiation of template type alias 'vec' requested here}}
}
#endif