diff options
Diffstat (limited to 'gcc/configure.ac')
| -rw-r--r-- | gcc/configure.ac | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/gcc/configure.ac b/gcc/configure.ac index 4dc7c109a26..9791a96c7bb 100644 --- a/gcc/configure.ac +++ b/gcc/configure.ac @@ -416,6 +416,33 @@ struct X<long long> { typedef long long t; }; ]], [[X<int64_t>::t x;]])],[],[AC_MSG_ERROR([error verifying int64_t uses long long])]) fi +# Check if C++ __builtin_constant_p works properly. Without the fix +# for PR 65656, g++ miscompiles __builtin_constant_p in wi::lrshift in +# wide-int.h. Add a check with PR 65656 testcase to verify that C++ +# __builtin_constant_p works properly. +if test "$GCC" = yes; then + saved_CFLAGS="$CFLAGS" + saved_CXXFLAGS="$CXXFLAGS" + CFLAGS="$CFLAGS -O -x c++ -std=c++11" + CXXFLAGS="$CXXFLAGS -O -x c++ -std=c++11" + AC_MSG_CHECKING(whether $CXX __builtin_constant_p works with constexpr) + AC_COMPILE_IFELSE([ +int +foo (int argc) +{ + constexpr bool x = __builtin_constant_p(argc); + return x ? 1 : 0; +} +], + [AC_MSG_RESULT([yes]) + AC_DEFINE(HAVE_WORKING_CXX_BUILTIN_CONSTANT_P, 1, +[Define this macro if C++ __builtin_constant_p with constexpr does not + crash with a variable.])], + [AC_MSG_RESULT([no])]) + CFLAGS="$saved_CFLAGS" + CXXFLAGS="$saved_CXXFLAGS" +fi + # Check whether compiler is affected by placement new aliasing bug (PR 29286). # If the host compiler is affected by the bug, and we build with optimization # enabled (which happens e.g. when cross-compiling), the pool allocator may |