Test cpow in all rounding modes.

This patch enables testing of cpow in all rounding modes using
ALL_RM_TEST.  There were two reasons this was previously deferred:

* MPC has complicated rounding-mode-dependent rules for the signs of
  exact zero real or imaginary parts in the result of mpc_pow.  Annex
  G does not impose any such requirements and I don't think glibc
  should try to implement any particular logic here.  This patch adds
  support for gen-auto-libm-tests passing the IGNORE_ZERO_INF_SIGN
  flag to libm-test.inc.

* Error accumulations in some tests in non-default rounding modes
  exceed the maximum error permitted in libm-test.inc.  This patch
  marks the problem tests with xfail-rounding.  (It might be possible
  to reduce the accumulations a bit by using round-to-nearest when
  cpow calls clog, but I don't think there's much point; the
  implementation approach for cpow is fundamentally deficient, as
  discussed in the existing bug for cpow inaccuracy which can
  reasonably be considered to cover these less-inaccurate cases as
  well.  It's possible that the test "cpow 2 0 10 0" will also need
  xfail-rounding on some platforms.)

Tested x86_64 and x86 and ulps updated accordingly.

	* math/gen-auto-libm-tests.c: Document use of
	ignore-zero-inf-sign.
	(input_flag_type): Add value flag_ignore_zero_inf_sign.
	(input_flags): Add ignore-zero-inf-sign.
	(output_for_one_input_case): Handle flag_ignore_zero_inf_sign.
	* math/gen-libm-test.pl (generate_testfile): Handle
	ignore-zero-inf-sign.
	* math/auto-libm-test-in: Mark some cpow tests with
	ignore-zero-inf-sign and some with xfail-rounding.
	* math/auto-libm-test-out: Regenerated.
	* math/libm-test.inc (cpow_test): Use ALL_RM_TEST.
	* sysdeps/i386/fpu/libm-test-ulps: Update.
	* sysdeps/x86_64/fpu/libm-test-ulps: Likewise.

1 files changed, 4 insertions, 0 deletions

diff --git a/math/gen-libm-test.pl b/math/gen-libm-test.pl
index 5f62872b21..b5d599ff4a 100755
--- a/math/gen-libm-test.pl
+++ b/math/gen-libm-test.pl
@@ -442,6 +442,10 @@ sub generate_testfile {
 	    }
 	  }
 	  $flags_conv = "";
+	  if (defined ($flag_cond{"ignore-zero-inf-sign"})) {
+	    $flags_conv .= or_cond_value ($flag_cond{"ignore-zero-inf-sign"},
+					  "IGNORE_ZERO_INF_SIGN", "0");
+	  }
 	  if (defined ($flag_cond{"no-test-inline"})) {
 	    $flags_conv .= or_cond_value ($flag_cond{"no-test-inline"},
 					  "NO_TEST_INLINE", "0");