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author | Tom Lane | 2017-12-14 22:19:27 +0000 |
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committer | Tom Lane | 2017-12-14 22:19:27 +0000 |
commit | 9220b00e57352fda988b187940f5d5ac4851a8bb (patch) | |
tree | 6a5420c3eb876cee87c2fa3f8ec72353dc7734e9 /configure | |
parent | 11b8f076c02b4ff0230430fb8d82c80acc450c90 (diff) |
Tighten configure's test for __builtin_constant_p().
Commit 9fa6f00b1 assumed that __builtin_constant_p("string literal")
is TRUE, if the compiler has that function at all. Buildfarm results
show that Sun Studio 12, at least, breaks that assumption. Removing
that usage would leave us with no mechanical check for a very fragile
coding requirement, so instead teach configure to ignore
__builtin_constant_p() if it doesn't behave that way. We could
complicate matters by distinguishing three cases (no such function,
vs does, vs doesn't work for string literals); but for now, that seems
unnecessary because our other existing uses of this function are just
fairly minor optimizations of non-returning elog/ereport. We can live
without that on the small population of compilers that act this way.
Discussion: https://postgr.es/m/22997.1513264066@sss.pgh.pa.us
Diffstat (limited to 'configure')
-rwxr-xr-x | configure | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/configure b/configure index ca76ef0ab22..58eafd31c58 100755 --- a/configure +++ b/configure @@ -11901,7 +11901,10 @@ if ${pgac_cv__builtin_constant_p+:} false; then : else cat confdefs.h - <<_ACEOF >conftest.$ac_ext /* end confdefs.h. */ -static int x; static int y[__builtin_constant_p(x) ? x : 1]; +static int x; + static int y[__builtin_constant_p(x) ? x : 1]; + static int z[__builtin_constant_p("string literal") ? 1 : x]; + _ACEOF if ac_fn_c_try_compile "$LINENO"; then : |