42 lines
1.2 KiB
Text
42 lines
1.2 KiB
Text
# On some platforms clang builtin implementations
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# require compiler-rt as a runtime library to use.
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#
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# See:
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# - https://bugs.llvm.org/show_bug.cgi?id=28629
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m4_define([_CHECK_RUNTIME_testbody], [[
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bool f(long long x, long long y, long long* p)
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{
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return __builtin_mul_overflow(x, y, p);
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}
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int main() { return 0; }
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]])
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AC_DEFUN([CHECK_RUNTIME_LIB], [
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AC_LANG_PUSH([C++])
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AC_MSG_CHECKING([for __builtin_mul_overflow])
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AC_LINK_IFELSE(
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[AC_LANG_SOURCE([_CHECK_RUNTIME_testbody])],
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[
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AC_MSG_RESULT([yes])
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AC_DEFINE([HAVE_BUILTIN_MUL_OVERFLOW], [1], [Define if you have a working __builtin_mul_overflow])
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],
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[
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ax_check_save_flags="$LDFLAGS"
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LDFLAGS="$LDFLAGS --rtlib=compiler-rt -lgcc_s"
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AC_LINK_IFELSE(
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[AC_LANG_SOURCE([_CHECK_RUNTIME_testbody])],
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[
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AC_MSG_RESULT([yes, with additional linker flags])
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RUNTIME_LDFLAGS="--rtlib=compiler-rt -lgcc_s"
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AC_DEFINE([HAVE_BUILTIN_MUL_OVERFLOW], [1], [Define if you have a working __builtin_mul_overflow])
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],
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[AC_MSG_RESULT([no])])
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LDFLAGS="$ax_check_save_flags"
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])
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AC_LANG_POP
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AC_SUBST([RUNTIME_LDFLAGS])
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])
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