Force "restrict" not to be used when compiling with xlc.

anarazel · anarazel · commit d133982d598c · 2017-10-13T12:15:06.000-07:00
Per buildfarm animal Hornet and followup manual testing by Noah Misch, it appears xlc miscompiles code using "restrict" in at least some cases. Allow disabling restrict usage with FORCE_DISABLE_RESTRICT=yes in template files, and do so for aix/xlc. Author: Andres Freund and Tom Lane Discussion: https://postgr.es/m/1820.1507918762@sss.pgh.pa.us
diff --git a/configure b/configure
@@ -12466,6 +12466,10 @@ fi
 # spelling it understands, because it conflicts with
 # __declspec(restrict). Therefore we define pg_restrict to the
 # appropriate definition, which presumably won't conflict.
+#
+# Allow platforms with buggy compilers to force restrict to not be
+# used by setting $FORCE_DISABLE_RESTRICT=yes in the relevant
+# template.
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for C/C++ restrict keyword" >&5
 $as_echo_n "checking for C/C++ restrict keyword... " >&6; }
 if ${ac_cv_c_restrict+:} false; then :
@@ -12512,7 +12516,7 @@ _ACEOF
  ;;
  esac
 
-if test "$ac_cv_c_restrict" = "no" ; then
+if test "$ac_cv_c_restrict" = "no" -o "x$FORCE_DISABLE_RESTRICT" = "xyes"; then
   pg_restrict=""
 else
   pg_restrict="$ac_cv_c_restrict"
diff --git a/configure.in b/configure.in
@@ -1329,8 +1329,12 @@ PGAC_TYPE_LOCALE_T
 # spelling it understands, because it conflicts with
 # __declspec(restrict). Therefore we define pg_restrict to the
 # appropriate definition, which presumably won't conflict.
+#
+# Allow platforms with buggy compilers to force restrict to not be
+# used by setting $FORCE_DISABLE_RESTRICT=yes in the relevant
+# template.
 AC_C_RESTRICT
-if test "$ac_cv_c_restrict" = "no" ; then
+if test "$ac_cv_c_restrict" = "no" -o "x$FORCE_DISABLE_RESTRICT" = "xyes"; then
   pg_restrict=""
 else
   pg_restrict="$ac_cv_c_restrict"
diff --git a/src/template/aix b/src/template/aix
@@ -10,6 +10,10 @@ if test "$GCC" != yes ; then
       CFLAGS="-O2 -qmaxmem=16384 -qsrcmsg"
       ;;
   esac
+
+  # Due to a compiler bug, see 20171013023536.GA492146@rfd.leadboat.com for details,
+  # force restrict not to be used when compiling with xlc.
+  FORCE_DISABLE_RESTRICT=yes
 fi
 
 # Native memset() is faster, tested on:
