From: Andres Freund <andres@anarazel.de>
Date: Fri, 13 Oct 2017 18:54:59 +0000 (-0700)
Subject: Force "restrict" not to be used when compiling with xlc.
X-Git-Tag: REL_11_BETA1~1385
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=d133982d598c7e6208d16cb4fc0b552151796603;p=postgresql

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

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
index cdcb3ceb0c..4ecd2e1922 100755
--- 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
index 32bb7bf940..cea7fd0755 100644
--- 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="$ac_cv_c_restrict"
diff --git a/src/template/aix b/src/template/aix
index b566ff129d..ed832849da 100644
--- a/src/template/aix
+++ b/src/template/aix
@@ -10,6 +10,10 @@ if test "$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: