diff --git a/INSTALL b/INSTALL
index 24e3c8d25b..85c8e4cef1 100644
--- a/INSTALL
+++ b/INSTALL
@@ -49,6 +49,12 @@ if 'CFLAGS' is specified it must enable optimization.  For example:
 
      $ ../glibc-VERSION/configure CC="gcc -m32" CFLAGS="-O3"
 
+   To test the GNU C Library with a different C compiler or a different
+C++ compiler, 'TEST_CC=COMPILER' and 'TEST_CXX=COMPILER' arguments can
+be passed to 'configure'.  For example:
+
+     $ ../glibc-VERSION/configure TEST_CC="gcc-6.4.1" TEST_CXX="g++-6.4.1"
+
    The following list describes all of the available options for
 'configure':
 
diff --git a/Makefile.in b/Makefile.in
index 3fe9e73645..ee9270491e 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -1,5 +1,17 @@
 srcdir = @srcdir@
 
+TEST_CC = @TEST_CC@
+TEST_CXX = @TEST_CXX@
+test-cc-option-wimplicit-fallthrough = @libc_cv_test_cc_wimplicit_fallthrough@
+test-config-cflags-mprefer-vector-width = @libc_cv_test_cc_mprefer_vector_width@
+test-config-cflags-signaling-nans = @libc_cv_test_cc_signaling_nans@
+test-config-cflags-wno-ignored-attributes = @libc_cv_test_wno_ignored_attributes@
+test-enable-cet = @test_enable_cet@
+test-have-mamx-tile = @libc_cv_test_x86_have_amx_tile@
+test-have-mtls-descriptor = @libc_cv_test_mtls_descriptor@
+test-have-static-pie = @libc_cv_test_static_pie@
+test-supported-fortify = @libc_cv_test_supported_fortify_source@
+
 # Uncomment the line below if you want to do parallel build.
 # PARALLELMFLAGS = -j 4
 
@@ -8,6 +20,20 @@ srcdir = @srcdir@
 all .DEFAULT:
 	$(MAKE) -r PARALLELMFLAGS="$(PARALLELMFLAGS)" -C $(srcdir) objdir=`pwd` $@
 
+check xcheck:
+	$(MAKE) -r PARALLELMFLAGS="$(PARALLELMFLAGS)" -C $(srcdir) \
+		CC="$(TEST_CC)" CXX="$(TEST_CXX)" \
+		cc-option-wimplicit-fallthrough="$(test-cc-option-wimplicit-fallthrough)" \
+		config-cflags-mprefer-vector-width="$(test-config-cflags-mprefer-vector-width)" \
+		config-cflags-signaling-nans="$(test-config-cflags-signaling-nans)" \
+		config-cflags-wno-ignored-attributes="$(test-config-cflags-wno-ignored-attributes)" \
+		enable-cet="$(test-enable-cet)" \
+		have-mamx-tile="$(test-have-mamx-tile)" \
+		have-mtls-descriptor="$(test-have-mtls-descriptor)" \
+		have-static-pie="$(test-have-static-pie)" \
+		supported-fortify="$(test-supported-fortify)" \
+		objdir=`pwd` $@
+
 install:
 	LC_ALL=C; export LC_ALL; \
 	$(MAKE) -r PARALLELMFLAGS="$(PARALLELMFLAGS)" -C $(srcdir) objdir=`pwd` $@
diff --git a/aclocal.m4 b/aclocal.m4
index d8c613faf7..88ed3a6b71 100644
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -315,3 +315,86 @@ case "$prefix" in
   fi
   ;;
 esac])
+
+dnl Run a test with TEST_CC.
+dnl LIBC_CHECK_TEST_CC([commands])
+AC_DEFUN([LIBC_CHECK_TEST_CC],
+[
+saved_CC="$CC"
+CC="$TEST_CC"
+[$1]
+CC="$saved_CC"
+])
+
+dnl Test a CC and TEST_CC compiler option or options with an empty input
+dnl file.
+dnl LIBC_TRY_CC_AND_TEST_CC_OPTION([message], [options],
+dnl   [CC-cache-id], [CC-action-if-true], [CC-action-if-false]
+dnl   [TEST_CC-cache-id], [TEST_CC-action-if-true], [TEST_CC-action-if-false])
+AC_DEFUN([LIBC_TRY_CC_AND_TEST_CC_OPTION],
+[
+AC_CACHE_CHECK([$1], $3,
+  [LIBC_TRY_CC_OPTION([$2], [$4], [$5])])
+if test "$TEST_CC" = "$CC"; then
+  $6=$[$3]
+else
+  LIBC_CHECK_TEST_CC(
+    AC_CACHE_CHECK([$1 in testing], $6,
+      [LIBC_TRY_CC_OPTION([$2], [$7], [$8])])
+  )
+fi
+])
+
+dnl Test a CC and TEST_CC compiler option or options with an input file.
+dnl LIBC_TRY_CC_AND_TEST_CC_COMMAND([message], [code], [options],
+dnl   [CC-cache-id], [CC-action-if-true], [CC-action-if-false]
+dnl   [TEST_CC-cache-id], [TEST_CC-action-if-true], [TEST_CC-action-if-false])
+AC_DEFUN([LIBC_TRY_CC_AND_TEST_CC_COMMAND],
+[
+cat > conftest.c <<EOF
+$2
+EOF
+AC_CACHE_CHECK([$1], $4, [dnl
+  if AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS $3 conftest.c -o conftest 1>&AS_MESSAGE_LOG_FD])
+  then
+    [$5]
+  else
+    [$6]
+  fi
+])
+if test "$TEST_CC" = "$CC"; then
+  $7=$[$4]
+else
+  LIBC_CHECK_TEST_CC(
+    AC_CACHE_CHECK([$1 in testing], $7, [dnl
+      if AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS $3 conftest.c -o conftest 1>&AS_MESSAGE_LOG_FD])
+      then
+	[$8]
+      else
+	[$9]
+      fi])
+  )
+fi
+rm -f conftest*])
+
+dnl Test if CC and TEST_CC can link with an input file.
+dnl LIBC_TRY_CC_AND_TEST_LINK([message], [code],
+dnl   [CC-cache-id], [CC-action-if-true], [CC-action-if-false]
+dnl   [TEST_CC-cache-id], [TEST_CC-action-if-true], [TEST_CC-action-if-false])
+AC_DEFUN([LIBC_TRY_CC_AND_TEST_LINK],
+[
+AC_CACHE_CHECK([$1], $3, [
+  AC_LINK_IFELSE([AC_LANG_PROGRAM([], [$2])],
+   [$4], [$5])
+])
+if test "$TEST_CC" = "$CC"; then
+  $6=$[$3]
+else
+  LIBC_CHECK_TEST_CC(
+    AC_CACHE_CHECK([$1 in testing], $6, [
+      AC_LINK_IFELSE([AC_LANG_PROGRAM([], [$2])],
+      [$7], [$8])
+    ])
+  )
+fi
+])
diff --git a/configure b/configure
index e99c0d23af..fbfe849474 100755
--- a/configure
+++ b/configure
@@ -620,6 +620,9 @@ DEFINES
 static_nss
 profile
 libc_cv_multidir
+libc_cv_test_x86_have_amx_tile
+test_enable_cet
+libc_cv_test_cc_mprefer_vector_width
 shared
 static
 ldd_rewrite_script
@@ -641,15 +644,21 @@ fortify_source
 no_fortify_source
 libc_cv_fortify_source
 enable_fortify_source
+libc_cv_test_supported_fortify_source
 have_selinux
 have_libcap
 have_libaudit
 LIBGD
+libc_cv_test_cc_wimplicit_fallthrough
 libc_cv_cc_loop_to_function
+libc_cv_test_cc_signaling_nans
 libc_cv_cc_submachine
 libc_cv_cc_nofma
+libc_cv_test_wno_ignored_attributes
+libc_cv_test_mtls_descriptor
 libc_cv_has_glob_dat
 libc_cv_fpie
+libc_cv_test_static_pie
 libc_cv_z_execstack
 ASFLAGS_config
 libc_cv_cc_with_libunwind
@@ -704,12 +713,14 @@ man_pages_version
 rtld_early_cflags
 extra_nonshared_cflags
 sysheaders
+TEST_CXX
 ac_ct_CXX
 CXXFLAGS
 CXX
 CPP
 cross_compiling
 BUILD_CC
+TEST_CC
 OBJEXT
 ac_ct_CC
 CPPFLAGS
@@ -819,10 +830,12 @@ CFLAGS
 LDFLAGS
 LIBS
 CPPFLAGS
+TEST_CC
 CPP
 CXX
 CXXFLAGS
-CCC'
+CCC
+TEST_CXX'
 ac_subdirs_all=''
 
 # Initialize some variables set by options.
@@ -1523,9 +1536,11 @@ Some influential environment variables:
   LIBS        libraries to pass to the linker, e.g. -l<library>
   CPPFLAGS    (Objective) C/C++ preprocessor flags, e.g. -I<include dir> if
               you have headers in a nonstandard directory <include dir>
+  TEST_CC     C compiler for testing
   CPP         C preprocessor
   CXX         C++ compiler command
   CXXFLAGS    C++ compiler flags
+  TEST_CXX    C++ compiler for testing
 
 Use these variables to override the choices made by 'configure' or to help
 it to find libraries and programs with nonstandard names/locations.
@@ -3806,6 +3821,10 @@ ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
 ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
 ac_compiler_gnu=$ac_cv_c_compiler_gnu
 
+
+if test -z "$TEST_CC"; then
+  TEST_CC="$CC"
+fi
 if test $host != $build; then
   for ac_prog in gcc cc
 do
@@ -4280,6 +4299,14 @@ ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
 ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
 ac_compiler_gnu=$ac_cv_c_compiler_gnu
 
+
+if test -z "$TEST_CXX"; then
+  saved_CXX=
+  TEST_CXX="$CXX"
+else
+  saved_CXX="$CXX"
+  CXX="$TEST_CXX"
+fi
 # It's useless to us if it can't link programs (e.g. missing -lstdc++).
 
 { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether $CXX can link programs" >&5
@@ -4357,6 +4384,9 @@ if test $libc_cv_cxx_link_ok != yes
 then :
   CXX=
 fi
+if test -n "$saved_CXX"; then
+  CXX="$saved_CXX"
+fi
 
 if test "`cd $srcdir; pwd -P`" = "`pwd -P`"; then
   as_fn_error $? "you must configure in a separate build directory" "$LINENO" 5
@@ -7103,6 +7133,7 @@ printf "%s\n" "$libc_linker_feature" >&6; }
 config_vars="$config_vars
 have-no-dynamic-linker = $libc_cv_no_dynamic_linker"
 
+
 { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for -static-pie" >&5
 printf %s "checking for -static-pie... " >&6; }
 if test ${libc_cv_static_pie+y}
@@ -7120,15 +7151,49 @@ then :
 else case e in #(
   e) libc_cv_static_pie=no ;;
 esac
-fi
- ;;
+fi ;;
 esac
 fi
 { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv_static_pie" >&5
 printf "%s\n" "$libc_cv_static_pie" >&6; }
+if test "$TEST_CC" = "$CC"; then
+  libc_cv_test_static_pie=$libc_cv_static_pie
+else
+
+saved_CC="$CC"
+CC="$TEST_CC"
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for -static-pie in testing" >&5
+printf %s "checking for -static-pie in testing... " >&6; }
+if test ${libc_cv_test_static_pie+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if { ac_try='${CC-cc} -static-pie -xc /dev/null -S -o /dev/null'
+  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; }
+then :
+  libc_cv_test_static_pie=yes
+else case e in #(
+  e) libc_cv_test_static_pie=no
+ ;;
+esac
+fi ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv_test_static_pie" >&5
+printf "%s\n" "$libc_cv_test_static_pie" >&6; }
+
+CC="$saved_CC"
+
+fi
+
 config_vars="$config_vars
 have-static-pie = $libc_cv_static_pie"
 
+
 { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for -fpie" >&5
 printf %s "checking for -fpie... " >&6; }
 if test ${libc_cv_fpie+y}
@@ -7190,70 +7255,144 @@ fi
 printf "%s\n" "$libc_cv_has_glob_dat" >&6; }
 
 
+conftest_code="
+__thread int i;
+void foo (void)
+{
+  i = 10;
+}
+"
+
+cat > conftest.c <<EOF
+$conftest_code
+EOF
 { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for tls descriptor support" >&5
 printf %s "checking for tls descriptor support... " >&6; }
 if test ${libc_cv_mtls_descriptor+y}
 then :
   printf %s "(cached) " >&6
 else case e in #(
-  e) cat > conftest.c <<EOF
-__thread int i;
-void foo (void)
-{
-  i = 10;
-}
-EOF
-if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS -fPIC -mtls-dialect=$mtls_descriptor -nostdlib -nostartfiles
-		   -shared conftest.c -o conftest 1>&5'
+  e)   if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS -fPIC -mtls-dialect=$mtls_descriptor -nostdlib -nostartfiles -shared conftest.c -o conftest 1>&5'
   { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
   (eval $ac_try) 2>&5
   ac_status=$?
   printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
   test $ac_status = 0; }; }
-then
-  libc_cv_mtls_descriptor=$mtls_descriptor
-else
-  libc_cv_mtls_descriptor=no
-fi
-rm -f conftest* ;;
+  then
+    libc_cv_mtls_descriptor=$mtls_descriptor
+  else
+    libc_cv_mtls_descriptor=no
+  fi
+ ;;
 esac
 fi
 { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv_mtls_descriptor" >&5
 printf "%s\n" "$libc_cv_mtls_descriptor" >&6; }
+if test "$TEST_CC" = "$CC"; then
+  libc_cv_test_mtls_descriptor=$libc_cv_mtls_descriptor
+else
+
+saved_CC="$CC"
+CC="$TEST_CC"
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for tls descriptor support in testing" >&5
+printf %s "checking for tls descriptor support in testing... " >&6; }
+if test ${libc_cv_test_mtls_descriptor+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e)       if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS -fPIC -mtls-dialect=$mtls_descriptor -nostdlib -nostartfiles -shared conftest.c -o conftest 1>&5'
+  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; }
+      then
+	libc_cv_test_mtls_descriptor=$mtls_descriptor
+      else
+	libc_cv_test_mtls_descriptor=no
+      fi ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv_test_mtls_descriptor" >&5
+printf "%s\n" "$libc_cv_test_mtls_descriptor" >&6; }
+
+CC="$saved_CC"
+
+fi
+rm -f conftest*
 config_vars="$config_vars
 have-mtls-descriptor = $libc_cv_mtls_descriptor"
 
+
+conftest_code="
+void __foo (void)
+{
+}
+extern __typeof (__foo) foo __attribute__ ((weak, alias ("__foo")));
+extern __typeof (__foo) bar __attribute__ ((weak, alias ("foo")));
+"
+
+cat > conftest.c <<EOF
+$conftest_code
+EOF
 { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if -Wno-ignored-attributes is required for aliases" >&5
 printf %s "checking if -Wno-ignored-attributes is required for aliases... " >&6; }
 if test ${libc_cv_wno_ignored_attributes+y}
 then :
   printf %s "(cached) " >&6
 else case e in #(
-  e) cat > conftest.c <<EOF
-void __foo (void)
-{
-}
-extern __typeof (__foo) foo __attribute__ ((weak, alias ("__foo")));
-extern __typeof (__foo) bar __attribute__ ((weak, alias ("foo")));
-EOF
-libc_cv_wno_ignored_attributes=""
-if ! { ac_try='${CC-cc} $CFLAGS $CPPFLAGS -Werror -c conftest.c'
+  e)   if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS -c -Werror -Wno-ignored-attributes conftest.c -o conftest 1>&5'
   { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
   (eval $ac_try) 2>&5
   ac_status=$?
   printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
   test $ac_status = 0; }; }
-then
-  libc_cv_wno_ignored_attributes="-Wno-ignored-attributes"
-fi
-rm -f conftest* ;;
+  then
+    libc_cv_wno_ignored_attributes="-Wno-ignored-attributes"
+  else
+    libc_cv_wno_ignored_attributes=
+  fi
+ ;;
 esac
 fi
 { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv_wno_ignored_attributes" >&5
 printf "%s\n" "$libc_cv_wno_ignored_attributes" >&6; }
+if test "$TEST_CC" = "$CC"; then
+  libc_cv_test_wno_ignored_attributes=$libc_cv_wno_ignored_attributes
+else
+
+saved_CC="$CC"
+CC="$TEST_CC"
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if -Wno-ignored-attributes is required for aliases in testing" >&5
+printf %s "checking if -Wno-ignored-attributes is required for aliases in testing... " >&6; }
+if test ${libc_cv_test_wno_ignored_attributes+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e)       if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS -c -Werror -Wno-ignored-attributes conftest.c -o conftest 1>&5'
+  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; }
+      then
+	libc_cv_test_wno_ignored_attributes="-Wno-ignored-attributes"
+      else
+	libc_cv_test_wno_ignored_attributes=
+      fi ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv_test_wno_ignored_attributes" >&5
+printf "%s\n" "$libc_cv_test_wno_ignored_attributes" >&6; }
+
+CC="$saved_CC"
+
+fi
+rm -f conftest*
 config_vars="$config_vars
 config-cflags-wno-ignored-attributes = $libc_cv_wno_ignored_attributes"
 
+
 { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether cc puts quotes around section names" >&5
 printf %s "checking whether cc puts quotes around section names... " >&6; }
 if test ${libc_cv_have_section_quotes+y}
@@ -7405,6 +7544,7 @@ printf "%s\n" "$libc_cv_cc_submachine" >&6; }
 fi
 
 
+
 { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for compiler option that -fsignaling-nans" >&5
 printf %s "checking for compiler option that -fsignaling-nans... " >&6; }
 if test ${libc_cv_cc_signaling_nans+y}
@@ -7422,15 +7562,48 @@ then :
 else case e in #(
   e) libc_cv_cc_signaling_nans= ;;
 esac
-fi
- ;;
+fi ;;
 esac
 fi
 { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv_cc_signaling_nans" >&5
 printf "%s\n" "$libc_cv_cc_signaling_nans" >&6; }
+if test "$TEST_CC" = "$CC"; then
+  libc_cv_test_cc_signaling_nans=$libc_cv_cc_signaling_nans
+else
+
+saved_CC="$CC"
+CC="$TEST_CC"
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for compiler option that -fsignaling-nans in testing" >&5
+printf %s "checking for compiler option that -fsignaling-nans in testing... " >&6; }
+if test ${libc_cv_test_cc_signaling_nans+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if { ac_try='${CC-cc} -Werror -fsignaling-nans -xc /dev/null -S -o /dev/null'
+  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; }
+then :
+  libc_cv_test_cc_signaling_nans=-fsignaling-nans
+else case e in #(
+  e) libc_cv_test_cc_signaling_nans= ;;
+esac
+fi ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv_test_cc_signaling_nans" >&5
+printf "%s\n" "$libc_cv_test_cc_signaling_nans" >&6; }
+
+CC="$saved_CC"
+
+fi
+
 config_vars="$config_vars
 config-cflags-signaling-nans = $libc_cv_cc_signaling_nans"
 
+
 { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if $CC accepts -fno-tree-loop-distribute-patterns with \
 __attribute__ ((__optimize__))" >&5
 printf %s "checking if $CC accepts -fno-tree-loop-distribute-patterns with \
@@ -7465,6 +7638,7 @@ if test $libc_cv_cc_loop_to_function = yes; then
 fi
 
 
+
 { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for -Wimplicit-fallthrough" >&5
 printf %s "checking for -Wimplicit-fallthrough... " >&6; }
 if test ${libc_cv_cc_wimplicit_fallthrough+y}
@@ -7480,17 +7654,50 @@ else case e in #(
 then :
   libc_cv_cc_wimplicit_fallthrough=-Wimplicit-fallthrough
 else case e in #(
-  e) libc_cv_cc_wimplicit_fallthrough= ;;
+  e) libc_cv_cc_wimplicit_fallthrough=-Wimplicit-fallthrough ;;
 esac
-fi
- ;;
+fi ;;
 esac
 fi
 { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv_cc_wimplicit_fallthrough" >&5
 printf "%s\n" "$libc_cv_cc_wimplicit_fallthrough" >&6; }
+if test "$TEST_CC" = "$CC"; then
+  libc_cv_test_cc_wimplicit_fallthrough=$libc_cv_cc_wimplicit_fallthrough
+else
+
+saved_CC="$CC"
+CC="$TEST_CC"
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for -Wimplicit-fallthrough in testing" >&5
+printf %s "checking for -Wimplicit-fallthrough in testing... " >&6; }
+if test ${libc_cv_test_cc_wimplicit_fallthrough+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if { ac_try='${CC-cc} -Werror -Wimplicit-fallthrough -xc /dev/null -S -o /dev/null'
+  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; }
+then :
+  libc_cv_test_cc_wimplicit_fallthrough=-Wimplicit-fallthrough
+else case e in #(
+  e) libc_cv_test_cc_wimplicit_fallthrough= ;;
+esac
+fi ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv_test_cc_wimplicit_fallthrough" >&5
+printf "%s\n" "$libc_cv_test_cc_wimplicit_fallthrough" >&6; }
+
+CC="$saved_CC"
+
+fi
+
 config_vars="$config_vars
 cc-option-wimplicit-fallthrough = $libc_cv_cc_wimplicit_fallthrough"
 
+
 { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for libgd" >&5
 printf %s "checking for libgd... " >&6; }
 if test "$with_gd" != "no"; then
@@ -7721,6 +7928,7 @@ fi
 no_fortify_source="-U_FORTIFY_SOURCE"
 fortify_source="${no_fortify_source}"
 
+
 { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for maximum supported _FORTIFY_SOURCE level" >&5
 printf %s "checking for maximum supported _FORTIFY_SOURCE level... " >&6; }
 if test ${libc_cv_supported_fortify_source+y}
@@ -7728,7 +7936,7 @@ then :
   printf %s "(cached) " >&6
 else case e in #(
   e)
-    cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
 int
@@ -7753,6 +7961,50 @@ esac
 fi
 { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv_supported_fortify_source" >&5
 printf "%s\n" "$libc_cv_supported_fortify_source" >&6; }
+if test "$TEST_CC" = "$CC"; then
+  libc_cv_test_supported_fortify_source=$libc_cv_supported_fortify_source
+else
+
+saved_CC="$CC"
+CC="$TEST_CC"
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for maximum supported _FORTIFY_SOURCE level in testing" >&5
+printf %s "checking for maximum supported _FORTIFY_SOURCE level in testing... " >&6; }
+if test ${libc_cv_test_supported_fortify_source+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e)
+      cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main (void)
+{
+__builtin_dynamic_object_size("", 0)
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"
+then :
+  libc_cv_test_supported_fortify_source=3
+else case e in #(
+  e) libc_cv_test_supported_fortify_source=2 ;;
+esac
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam \
+    conftest$ac_exeext conftest.$ac_ext
+     ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv_test_supported_fortify_source" >&5
+printf "%s\n" "$libc_cv_test_supported_fortify_source" >&6; }
+
+CC="$saved_CC"
+
+fi
+
+
 
 case $enable_fortify_source in #(
   yes) :
@@ -8244,6 +8496,11 @@ fi
 config_vars="$config_vars
 enable-static-pie = $libc_cv_static_pie"
 
+# Support configure.ac under sysdeps.
+
+
+
+
 # Set the `multidir' variable by grabbing the variable from the compiler.
 # We do it once and save the result in a generated makefile.
 libc_cv_multidir=`${CC-cc} $CFLAGS $CPPFLAGS -print-multi-directory`
diff --git a/configure.ac b/configure.ac
index 06a9c3f252..1b0e07dfab 100644
--- a/configure.ac
+++ b/configure.ac
@@ -46,6 +46,11 @@ AC_CONFIG_SUBDIRS()
 AC_CANONICAL_HOST
 
 AC_PROG_CC
+AC_ARG_VAR([TEST_CC],
+	   [C compiler for testing])
+if test -z "$TEST_CC"; then
+  TEST_CC="$CC"
+fi
 if test $host != $build; then
   AC_CHECK_PROGS(BUILD_CC, gcc cc)
 fi
@@ -70,6 +75,15 @@ AC_ARG_ENABLE([static-c++-link-check],
 
 # We need the C++ compiler only for testing.
 AC_PROG_CXX
+AC_ARG_VAR([TEST_CXX],
+	   [C++ compiler for testing])
+if test -z "$TEST_CXX"; then
+  saved_CXX=
+  TEST_CXX="$CXX"
+else
+  saved_CXX="$CXX"
+  CXX="$TEST_CXX"
+fi
 # It's useless to us if it can't link programs (e.g. missing -lstdc++).
 AC_CACHE_CHECK([whether $CXX can link programs], libc_cv_cxx_link_ok, [dnl
 AC_LANG_PUSH([C++])
@@ -97,6 +111,9 @@ main()
 fi
 AC_LANG_POP([C++])])
 AS_IF([test $libc_cv_cxx_link_ok != yes], [CXX=])
+if test -n "$saved_CXX"; then
+  CXX="$saved_CXX"
+fi
 
 if test "`cd $srcdir; pwd -P`" = "`pwd -P`"; then
   AC_MSG_ERROR([you must configure in a separate build directory])
@@ -1278,12 +1295,14 @@ LIBC_LINKER_FEATURE([--no-dynamic-linker],
 		    [libc_cv_no_dynamic_linker=no])
 LIBC_CONFIG_VAR([have-no-dynamic-linker], [$libc_cv_no_dynamic_linker])
 
-AC_CACHE_CHECK(for -static-pie, libc_cv_static_pie, [dnl
-LIBC_TRY_CC_OPTION([-static-pie],
-		   [libc_cv_static_pie=yes],
-		   [libc_cv_static_pie=no])
-])
+LIBC_TRY_CC_AND_TEST_CC_OPTION(for -static-pie, [-static-pie],
+  libc_cv_static_pie,
+  [libc_cv_static_pie=yes], [libc_cv_static_pie=no],
+  libc_cv_test_static_pie,
+  [libc_cv_test_static_pie=yes], [libc_cv_test_static_pie=no]
+)
 LIBC_CONFIG_VAR([have-static-pie], [$libc_cv_static_pie])
+AC_SUBST(libc_cv_test_static_pie)
 
 AC_CACHE_CHECK(for -fpie, libc_cv_fpie, [dnl
 LIBC_TRY_CC_OPTION([-fpie], [libc_cv_fpie=yes], [libc_cv_fpie=no])
@@ -1314,46 +1333,48 @@ fi
 rm -f conftest*])
 AC_SUBST(libc_cv_has_glob_dat)
 
-AC_CACHE_CHECK([for tls descriptor support], libc_cv_mtls_descriptor,
-[dnl
-cat > conftest.c <<EOF
+conftest_code="
 __thread int i;
 void foo (void)
 {
   i = 10;
 }
-EOF
-if AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS -fPIC -mtls-dialect=$mtls_descriptor -nostdlib -nostartfiles
-		   -shared conftest.c -o conftest 1>&AS_MESSAGE_LOG_FD])
-then
-  libc_cv_mtls_descriptor=$mtls_descriptor
-else
-  libc_cv_mtls_descriptor=no
-fi
-rm -f conftest*])
+"
+LIBC_TRY_CC_AND_TEST_CC_COMMAND([for tls descriptor support],
+  [$conftest_code],
+  [-fPIC -mtls-dialect=$mtls_descriptor -nostdlib -nostartfiles -shared],
+  libc_cv_mtls_descriptor,
+  [libc_cv_mtls_descriptor=$mtls_descriptor],
+  [libc_cv_mtls_descriptor=no],
+  libc_cv_test_mtls_descriptor,
+  [libc_cv_test_mtls_descriptor=$mtls_descriptor],
+  [libc_cv_test_mtls_descriptor=no])
 LIBC_CONFIG_VAR([have-mtls-descriptor], [$libc_cv_mtls_descriptor])
+AC_SUBST(libc_cv_test_mtls_descriptor)
 
 dnl clang emits an warning for a double alias redirection, to warn the
 dnl original symbol is sed even when weak definition overrides it.
 dnl It is a usual pattern for weak_alias, where multiple alias point to
 dnl same symbol.
-AC_CACHE_CHECK([if -Wno-ignored-attributes is required for aliases],
-	       libc_cv_wno_ignored_attributes, [dnl
-cat > conftest.c <<EOF
+conftest_code="
 void __foo (void)
 {
 }
 extern __typeof (__foo) foo __attribute__ ((weak, alias ("__foo")));
 extern __typeof (__foo) bar __attribute__ ((weak, alias ("foo")));
-EOF
-libc_cv_wno_ignored_attributes=""
-if ! AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS -Werror -c conftest.c])
-then
-  libc_cv_wno_ignored_attributes="-Wno-ignored-attributes"
-fi
-rm -f conftest*])
+"
+LIBC_TRY_CC_AND_TEST_CC_COMMAND([if -Wno-ignored-attributes is required for aliases],
+  [$conftest_code],
+  [-c -Werror -Wno-ignored-attributes],
+  libc_cv_wno_ignored_attributes,
+  [libc_cv_wno_ignored_attributes="-Wno-ignored-attributes"],
+  [libc_cv_wno_ignored_attributes=],
+  libc_cv_test_wno_ignored_attributes,
+  [libc_cv_test_wno_ignored_attributes="-Wno-ignored-attributes"],
+  [libc_cv_test_wno_ignored_attributes=])
 LIBC_CONFIG_VAR([config-cflags-wno-ignored-attributes],
 		[$libc_cv_wno_ignored_attributes])
+AC_SUBST(libc_cv_test_wno_ignored_attributes)
 
 AC_CACHE_CHECK(whether cc puts quotes around section names,
 	       libc_cv_have_section_quotes,
@@ -1440,14 +1461,17 @@ fi
 AC_SUBST(libc_cv_cc_submachine)
 
 dnl Determine if compiler supports -fsignaling-nans
-AC_CACHE_CHECK([for compiler option that -fsignaling-nans],
-	       libc_cv_cc_signaling_nans, [dnl
-LIBC_TRY_CC_OPTION([-Werror -fsignaling-nans],
-		   [libc_cv_cc_signaling_nans=-fsignaling-nans],
-		   [libc_cv_cc_signaling_nans=])
-])
+LIBC_TRY_CC_AND_TEST_CC_OPTION([for compiler option that -fsignaling-nans],
+  [-Werror -fsignaling-nans],
+  libc_cv_cc_signaling_nans,
+  [libc_cv_cc_signaling_nans=-fsignaling-nans],
+  [libc_cv_cc_signaling_nans=],
+  libc_cv_test_cc_signaling_nans,
+  [libc_cv_test_cc_signaling_nans=-fsignaling-nans],
+  [libc_cv_test_cc_signaling_nans=])
 LIBC_CONFIG_VAR([config-cflags-signaling-nans],
 		[$libc_cv_cc_signaling_nans])
+AC_SUBST(libc_cv_test_cc_signaling_nans)
 
 AC_CACHE_CHECK(if $CC accepts -fno-tree-loop-distribute-patterns with \
 __attribute__ ((__optimize__)), libc_cv_cc_loop_to_function, [dnl
@@ -1467,14 +1491,17 @@ if test $libc_cv_cc_loop_to_function = yes; then
 fi
 AC_SUBST(libc_cv_cc_loop_to_function)
 
-AC_CACHE_CHECK([for -Wimplicit-fallthrough],
-	       libc_cv_cc_wimplicit_fallthrough, [dnl
-LIBC_TRY_CC_OPTION([-Werror -Wimplicit-fallthrough],
-		   [libc_cv_cc_wimplicit_fallthrough=-Wimplicit-fallthrough],
-		   [libc_cv_cc_wimplicit_fallthrough=])
-])
+LIBC_TRY_CC_AND_TEST_CC_OPTION([for -Wimplicit-fallthrough],
+  [-Werror -Wimplicit-fallthrough],
+  libc_cv_cc_wimplicit_fallthrough,
+  [libc_cv_cc_wimplicit_fallthrough=-Wimplicit-fallthrough],
+  [libc_cv_cc_wimplicit_fallthrough=-Wimplicit-fallthrough],
+  libc_cv_test_cc_wimplicit_fallthrough,
+  [libc_cv_test_cc_wimplicit_fallthrough=-Wimplicit-fallthrough],
+  [libc_cv_test_cc_wimplicit_fallthrough=])
 LIBC_CONFIG_VAR([cc-option-wimplicit-fallthrough],
 		[$libc_cv_cc_wimplicit_fallthrough])
+AC_SUBST(libc_cv_test_cc_wimplicit_fallthrough)
 
 dnl Check whether we have the gd library available.
 AC_MSG_CHECKING(for libgd)
@@ -1538,12 +1565,15 @@ dnl support it
 no_fortify_source="-U_FORTIFY_SOURCE"
 fortify_source="${no_fortify_source}"
 
-AC_CACHE_CHECK([for maximum supported _FORTIFY_SOURCE level],
-	       [libc_cv_supported_fortify_source], [
-    AC_LINK_IFELSE([AC_LANG_PROGRAM([], [__builtin_dynamic_object_size("", 0)])],
-        [libc_cv_supported_fortify_source=3],
-        [libc_cv_supported_fortify_source=2])
-])
+LIBC_TRY_CC_AND_TEST_LINK([for maximum supported _FORTIFY_SOURCE level],
+  [__builtin_dynamic_object_size("", 0)],
+  libc_cv_supported_fortify_source,
+  [libc_cv_supported_fortify_source=3],
+  [libc_cv_supported_fortify_source=2],
+  libc_cv_test_supported_fortify_source,
+  [libc_cv_test_supported_fortify_source=3],
+  [libc_cv_test_supported_fortify_source=2])
+AC_SUBST(libc_cv_test_supported_fortify_source)
 
 AS_CASE([$enable_fortify_source],
         [yes], [libc_cv_fortify_source=yes enable_fortify_source=$libc_cv_supported_fortify_source],
@@ -1835,6 +1865,11 @@ if test "$libc_cv_static_pie" = "yes"; then
 fi
 LIBC_CONFIG_VAR([enable-static-pie], [$libc_cv_static_pie])
 
+# Support configure.ac under sysdeps.
+AC_SUBST(libc_cv_test_cc_mprefer_vector_width)
+AC_SUBST(test_enable_cet)
+AC_SUBST(libc_cv_test_x86_have_amx_tile)
+
 # Set the `multidir' variable by grabbing the variable from the compiler.
 # We do it once and save the result in a generated makefile.
 libc_cv_multidir=`${CC-cc} $CFLAGS $CPPFLAGS -print-multi-directory`
diff --git a/manual/install.texi b/manual/install.texi
index 3e68a3d823..61745b88d8 100644
--- a/manual/install.texi
+++ b/manual/install.texi
@@ -75,6 +75,15 @@ and @theglibc{} cannot be compiled without optimization, so if
 $ ../glibc-@var{version}/configure CC="gcc -m32" CFLAGS="-O3"
 @end smallexample
 
+To test @theglibc{} with a different C compiler or a different C++
+compiler, @samp{TEST_CC=@var{compiler}} and
+@samp{TEST_CXX=@var{compiler}} arguments can be passed to
+@code{configure}.  For example:
+
+@smallexample
+$ ../glibc-@var{version}/configure TEST_CC="gcc-6.4.1" TEST_CXX="g++-6.4.1"
+@end smallexample
+
 The following list describes all of the available options for
  @code{configure}:
 
diff --git a/sysdeps/x86_64/configure b/sysdeps/x86_64/configure
index 231e6ff128..5846b67c2f 100755
--- a/sysdeps/x86_64/configure
+++ b/sysdeps/x86_64/configure
@@ -1,8 +1,9 @@
 # This file is generated from configure.ac by Autoconf.  DO NOT EDIT!
  # Local configure fragment for sysdeps/x86_64.
 
-{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking -mprefer-vector-width=128" >&5
-printf %s "checking -mprefer-vector-width=128... " >&6; }
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for -mprefer-vector-width=128" >&5
+printf %s "checking for -mprefer-vector-width=128... " >&6; }
 if test ${libc_cv_cc_mprefer_vector_width+y}
 then :
   printf %s "(cached) " >&6
@@ -18,12 +19,44 @@ then :
 else case e in #(
   e) libc_cv_cc_mprefer_vector_width=no ;;
 esac
-fi
- ;;
+fi ;;
 esac
 fi
 { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv_cc_mprefer_vector_width" >&5
 printf "%s\n" "$libc_cv_cc_mprefer_vector_width" >&6; }
+if test "$TEST_CC" = "$CC"; then
+  libc_cv_test_cc_mprefer_vector_width=$libc_cv_cc_mprefer_vector_width
+else
+
+saved_CC="$CC"
+CC="$TEST_CC"
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for -mprefer-vector-width=128 in testing" >&5
+printf %s "checking for -mprefer-vector-width=128 in testing... " >&6; }
+if test ${libc_cv_test_cc_mprefer_vector_width+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if { ac_try='${CC-cc} -mprefer-vector-width=128 -xc /dev/null -S -o /dev/null'
+  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; }
+then :
+  libc_cv_test_cc_mprefer_vector_width=yes
+else case e in #(
+  e) libc_cv_test_cc_mprefer_vector_width=no ;;
+esac
+fi ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv_test_cc_mprefer_vector_width" >&5
+printf "%s\n" "$libc_cv_test_cc_mprefer_vector_width" >&6; }
+
+CC="$saved_CC"
+
+fi
+
 config_vars="$config_vars
 config-cflags-mprefer-vector-width = $libc_cv_cc_mprefer_vector_width"
 
@@ -66,34 +99,73 @@ if test x"$build_mathvec" = xnotset; then
   build_mathvec=yes
 fi
 
+test_enable_cet=$enable_cet
 if test $enable_cet != no; then
   # Check if CET can be enabled.
-  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether CET can be enabled" >&5
+  conftest_code="
+#if !defined __CET__ || __CET__ != 3
+# error CET is not available.
+#endif
+"
+
+cat > conftest.c <<EOF
+$conftest_code
+EOF
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether CET can be enabled" >&5
 printf %s "checking whether CET can be enabled... " >&6; }
 if test ${libc_cv_x86_cet_available+y}
 then :
   printf %s "(cached) " >&6
 else case e in #(
-  e) cat > conftest.c <<EOF
-#if !defined __CET__ || __CET__ != 3
-# error CET isn't available.
-#endif
-EOF
-		 if { ac_try='${CC-cc} -c $CFLAGS -fcf-protection -include cet.h conftest.c 1>&5'
+  e)   if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS -c -fcf-protection -include cet.h conftest.c -o conftest 1>&5'
   { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
   (eval $ac_try) 2>&5
   ac_status=$?
   printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
-  test $ac_status = 0; }; }; then
-		   libc_cv_x86_cet_available=yes
-		 else
-		   libc_cv_x86_cet_available=no
-		 fi
-		 rm -rf conftest* ;;
+  test $ac_status = 0; }; }
+  then
+    libc_cv_x86_cet_available=yes
+  else
+    libc_cv_x86_cet_available=no
+  fi
+ ;;
 esac
 fi
 { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv_x86_cet_available" >&5
 printf "%s\n" "$libc_cv_x86_cet_available" >&6; }
+if test "$TEST_CC" = "$CC"; then
+  libc_cv_test_x86_cet_available=$libc_cv_x86_cet_available
+else
+
+saved_CC="$CC"
+CC="$TEST_CC"
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether CET can be enabled in testing" >&5
+printf %s "checking whether CET can be enabled in testing... " >&6; }
+if test ${libc_cv_test_x86_cet_available+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e)       if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS -c -fcf-protection -include cet.h conftest.c -o conftest 1>&5'
+  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; }
+      then
+	libc_cv_test_x86_cet_available=yes
+      else
+	libc_cv_test_x86_cet_available=no
+      fi ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv_test_x86_cet_available" >&5
+printf "%s\n" "$libc_cv_test_x86_cet_available" >&6; }
+
+CC="$saved_CC"
+
+fi
+rm -f conftest*
+    test_enable_cet=$libc_cv_test_x86_cet_available
   if test $libc_cv_x86_cet_available != yes; then
     as_fn_error $? "$CC doesn't support CET" "$LINENO" 5
   fi
@@ -139,31 +211,75 @@ config_vars="$config_vars
 enable-cet = $enable_cet"
 
 # Check if -mamx-tile works properly.
+check_x86_have_amx_tile ()
+{
+  eval $1=no
+  if grep -q __builtin_ia32_ldtilecfg conftest; then
+    eval $1=yes
+  fi
+}
+
+conftest_code="
+#include <x86intrin.h>
+"
+
+cat > conftest.c <<EOF
+$conftest_code
+EOF
 { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether -mamx-tile works properly" >&5
 printf %s "checking whether -mamx-tile works properly... " >&6; }
 if test ${libc_cv_x86_have_amx_tile+y}
 then :
   printf %s "(cached) " >&6
 else case e in #(
-  e) cat > conftest.c <<EOF
-#include <x86intrin.h>
-EOF
-	       libc_cv_x86_have_amx_tile=no
-	       if { ac_try='${CC-cc} -E $CFLAGS -mamx-tile conftest.c > conftest.i'
+  e)   if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS -E -mamx-tile conftest.c -o conftest 1>&5'
   { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
   (eval $ac_try) 2>&5
   ac_status=$?
   printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
-  test $ac_status = 0; }; }; then
-		 if grep -q __builtin_ia32_ldtilecfg conftest.i; then
-		   libc_cv_x86_have_amx_tile=yes
-	         fi
-	       fi
-	       rm -rf conftest* ;;
+  test $ac_status = 0; }; }
+  then
+    check_x86_have_amx_tile libc_cv_x86_have_amx_tile
+  else
+    libc_cv_x86_have_amx_tile=no
+  fi
+ ;;
 esac
 fi
 { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv_x86_have_amx_tile" >&5
 printf "%s\n" "$libc_cv_x86_have_amx_tile" >&6; }
+if test "$TEST_CC" = "$CC"; then
+  libc_cv_test_x86_have_amx_tile=$libc_cv_x86_have_amx_tile
+else
+
+saved_CC="$CC"
+CC="$TEST_CC"
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether -mamx-tile works properly in testing" >&5
+printf %s "checking whether -mamx-tile works properly in testing... " >&6; }
+if test ${libc_cv_test_x86_have_amx_tile+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e)       if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS -E -mamx-tile conftest.c -o conftest 1>&5'
+  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; }
+      then
+	check_x86_have_amx_tile libc_cv_test_x86_have_amx_tile
+      else
+	libc_cv_test_x86_have_amx_tile=no
+      fi ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv_test_x86_have_amx_tile" >&5
+printf "%s\n" "$libc_cv_test_x86_have_amx_tile" >&6; }
+
+CC="$saved_CC"
+
+fi
+rm -f conftest*
 config_vars="$config_vars
 have-mamx-tile = $libc_cv_x86_have_amx_tile"
 
diff --git a/sysdeps/x86_64/configure.ac b/sysdeps/x86_64/configure.ac
index c7b68544a2..fcf457d03b 100644
--- a/sysdeps/x86_64/configure.ac
+++ b/sysdeps/x86_64/configure.ac
@@ -2,11 +2,14 @@ GLIBC_PROVIDES dnl See aclocal.m4 in the top level source directory.
 # Local configure fragment for sysdeps/x86_64.
 
 dnl Check if -mprefer-vector-width=128 works.
-AC_CACHE_CHECK(-mprefer-vector-width=128, libc_cv_cc_mprefer_vector_width, [dnl
-LIBC_TRY_CC_OPTION([-mprefer-vector-width=128],
-		   [libc_cv_cc_mprefer_vector_width=yes],
-		   [libc_cv_cc_mprefer_vector_width=no])
-])
+LIBC_TRY_CC_AND_TEST_CC_OPTION([for -mprefer-vector-width=128],
+  [-mprefer-vector-width=128],
+  libc_cv_cc_mprefer_vector_width,
+  [libc_cv_cc_mprefer_vector_width=yes],
+  [libc_cv_cc_mprefer_vector_width=no],
+  libc_cv_test_cc_mprefer_vector_width,
+  [libc_cv_test_cc_mprefer_vector_width=yes],
+  [libc_cv_test_cc_mprefer_vector_width=no])
 LIBC_CONFIG_VAR([config-cflags-mprefer-vector-width],
 		[$libc_cv_cc_mprefer_vector_width])
 
@@ -18,21 +21,24 @@ if test x"$build_mathvec" = xnotset; then
   build_mathvec=yes
 fi
 
+test_enable_cet=$enable_cet
 if test $enable_cet != no; then
   # Check if CET can be enabled.
-  AC_CACHE_CHECK(whether CET can be enabled,
-		 libc_cv_x86_cet_available, [dnl
-cat > conftest.c <<EOF
+  conftest_code="
 #if !defined __CET__ || __CET__ != 3
-# error CET isn't available.
+# error CET is not available.
 #endif
-EOF
-		 if AC_TRY_COMMAND(${CC-cc} -c $CFLAGS -fcf-protection -include cet.h conftest.c 1>&AS_MESSAGE_LOG_FD); then
-		   libc_cv_x86_cet_available=yes
-		 else
-		   libc_cv_x86_cet_available=no
-		 fi
-		 rm -rf conftest*])
+"
+  LIBC_TRY_CC_AND_TEST_CC_COMMAND([whether CET can be enabled],
+    [$conftest_code],
+    [-c -fcf-protection -include cet.h],
+    libc_cv_x86_cet_available,
+    [libc_cv_x86_cet_available=yes],
+    [libc_cv_x86_cet_available=no],
+    libc_cv_test_x86_cet_available,
+    [libc_cv_test_x86_cet_available=yes],
+    [libc_cv_test_x86_cet_available=no])
+    test_enable_cet=$libc_cv_test_x86_cet_available
   if test $libc_cv_x86_cet_available != yes; then
     AC_MSG_ERROR([$CC doesn't support CET])
   fi
@@ -62,18 +68,26 @@ fi
 LIBC_CONFIG_VAR([enable-cet], [$enable_cet])
 
 # Check if -mamx-tile works properly.
-AC_CACHE_CHECK(whether -mamx-tile works properly,
-	       libc_cv_x86_have_amx_tile, [dnl
-cat > conftest.c <<EOF
+check_x86_have_amx_tile ()
+{
+  eval $1=no
+  if grep -q __builtin_ia32_ldtilecfg conftest; then
+    eval $1=yes
+  fi
+}
+
+conftest_code="
 #include <x86intrin.h>
-EOF
-	       libc_cv_x86_have_amx_tile=no
-	       if AC_TRY_COMMAND(${CC-cc} -E $CFLAGS -mamx-tile conftest.c > conftest.i); then
-		 if grep -q __builtin_ia32_ldtilecfg conftest.i; then
-		   libc_cv_x86_have_amx_tile=yes
-	         fi
-	       fi
-	       rm -rf conftest*])
+"
+LIBC_TRY_CC_AND_TEST_CC_COMMAND([whether -mamx-tile works properly],
+  [$conftest_code],
+  [-E -mamx-tile],
+  libc_cv_x86_have_amx_tile,
+  [check_x86_have_amx_tile libc_cv_x86_have_amx_tile],
+  [libc_cv_x86_have_amx_tile=no],
+  libc_cv_test_x86_have_amx_tile,
+  [check_x86_have_amx_tile libc_cv_test_x86_have_amx_tile],
+  [libc_cv_test_x86_have_amx_tile=no])
 LIBC_CONFIG_VAR([have-mamx-tile], [$libc_cv_x86_have_amx_tile])
 
 # Check if -mapxf is enabled.