Remove --disable-atomics, require 32 bit atomics.

Modern versions of all relevant architectures and tool chains have
atomics support.  Since edadeb07, there is no remaining reason to carry
code that simulates atomic flags and uint32 imperfectly with spinlocks.
64 bit atomics are still emulated with spinlocks, if needed, for now.

Any modern compiler capable of implementing C11 <stdatomic.h> must have
the underlying operations we need, though we don't require C11 yet.  We
detect certain compilers and architectures, so hypothetical new systems
might need adjustments here.

Reviewed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Tom Lane <[email protected]> (concept, not the patch)
Reviewed-by: Andres Freund <[email protected]> (concept, not the patch)
Discussion: https://postgr.es/m/3351991.1697728588%40sss.pgh.pa.us

1 files changed, 0 insertions, 40 deletions

diff --git a/configure b/configure
index f8deaa8d78a..8f684f7945e 100755
--- a/configure
+++ b/configure
@@ -836,7 +836,6 @@ enable_integer_datetimes
 enable_nls
 with_pgport
 enable_rpath
-enable_atomics
 enable_debug
 enable_profiling
 enable_coverage
@@ -1528,7 +1527,6 @@ Optional Features:
                           enable Native Language Support
   --disable-rpath         do not embed shared library search path in
                           executables
-  --disable-atomics       do not use atomic operations
   --enable-debug          build with debugging symbols (-g)
   --enable-profiling      build with profiling enabled
   --enable-coverage       build with coverage testing instrumentation
@@ -3265,33 +3263,6 @@ fi
 
 
 #
-# Atomic operations
-#
-
-
-# Check whether --enable-atomics was given.
-if test "${enable_atomics+set}" = set; then :
-  enableval=$enable_atomics;
-  case $enableval in
-    yes)
-      :
-      ;;
-    no)
-      :
-      ;;
-    *)
-      as_fn_error $? "no argument expected for --enable-atomics option" "$LINENO" 5
-      ;;
-  esac
-
-else
-  enable_atomics=yes
-
-fi
-
-
-
-#
 # --enable-debug adds -g to compiler flags
 #
 
@@ -12156,17 +12127,6 @@ fi
 
 fi
 
-if test "$enable_atomics" = yes; then
-
-$as_echo "#define HAVE_ATOMICS 1" >>confdefs.h
-
-else
-  { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING:
-*** Not using atomic operations will cause poor performance." >&5
-$as_echo "$as_me: WARNING:
-*** Not using atomic operations will cause poor performance." >&2;}
-fi
-
 if test "$with_gssapi" = yes ; then
   if test "$PORTNAME" != "win32"; then
     { $as_echo "$as_me:${as_lineno-$LINENO}: checking for library containing gss_store_cred_into" >&5