From bc18126a6bcb85b51dc082c3ef4417dc016ebd9c Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Mon, 20 Mar 2017 13:35:21 -0400
Subject: Add configure test to see if the C compiler has gcc-style computed
 gotos.

We'll need this for the upcoming patch to speed up expression evaluation.
Might as well push it now to see if it behaves sanely in the buildfarm.

Andres Freund

Discussion: https://postgr.es/m/20170320062511.hp5qeurtxrwsvfxr@alap3.anarazel.de
---
 configure | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

(limited to 'configure')

diff --git a/configure b/configure
index b5cdebb510b..9528622421e 100755
--- a/configure
+++ b/configure
@@ -11531,6 +11531,40 @@ if test x"$pgac_cv__builtin_unreachable" = xyes ; then
 
 $as_echo "#define HAVE__BUILTIN_UNREACHABLE 1" >>confdefs.h
 
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for computed goto support" >&5
+$as_echo_n "checking for computed goto support... " >&6; }
+if ${pgac_cv_computed_goto+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+void *labeladdrs[] = {&&my_label};
+  goto *labeladdrs[0];
+  my_label:
+  return 1;
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  pgac_cv_computed_goto=yes
+else
+  pgac_cv_computed_goto=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $pgac_cv_computed_goto" >&5
+$as_echo "$pgac_cv_computed_goto" >&6; }
+if test x"$pgac_cv_computed_goto" = xyes ; then
+
+$as_echo "#define HAVE_COMPUTED_GOTO 1" >>confdefs.h
+
 fi
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for __VA_ARGS__" >&5
 $as_echo_n "checking for __VA_ARGS__... " >&6; }
-- 
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