diff options
| -rw-r--r-- | CMakeLists.txt | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/CMakeLists.txt b/CMakeLists.txt index 19ae4814..9716f350 100644 --- a/CMakeLists.txt +++ b/CMakeLists.txt @@ -74,9 +74,28 @@ string(REGEX REPLACE .*$" "\\1.\\2.\\3" PACKAGE_VERSION "${PACKAGE_VERSION}") +# With several compilers, CMAKE_BUILD_TYPE=Release uses -O3 optimization +# which results in bigger code without a clear difference in speed. If +# no user-defined CMAKE_C_FLAGS_RELEASE is present, override -O3 to -O2 +# to make it possible to recommend CMAKE_BUILD_TYPE=Release. +if(NOT DEFINED CMAKE_C_FLAGS_RELEASE) + set(OVERRIDE_O3_IN_C_FLAGS_RELEASE ON) +endif() + # Among other things, this gives us variables xz_VERSION and xz_VERSION_MAJOR. project(xz VERSION "${PACKAGE_VERSION}" LANGUAGES C) +if(OVERRIDE_O3_IN_C_FLAGS_RELEASE) + # Looking at CMake's source, there aren't any _FLAGS_RELEASE_INIT + # entries where "-O3" would appear as part of some other option, + # thus a simple search and replace should be fine. + string(REPLACE -O3 -O2 CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE}") + + # Update the cache value while keeping its docstring unchanged. + set_property(CACHE CMAKE_C_FLAGS_RELEASE + PROPERTY VALUE "${CMAKE_C_FLAGS_RELEASE}") +endif() + # We need a compiler that supports enough C99 or newer (variable-length arrays # aren't needed, those are optional in C17). Setting CMAKE_C_STANDARD here # makes it the default for all targets. It doesn't affect the INTERFACE so |