[PATCH][testsuite] Fix arm options in gcc.dg/lto/20110201-1_0.c

[Kyrill Tkachov <kyrylo dot tkachov at foss dot arm dot com>]

Hi all,

This test fails on arm hardfloat targets because it sets an explicit -mfloat-abi=softfp.
The usual approach to setting the NEON options is to use dg-add-options arm_neon.
But in the lto tests we don't have that framework, we can only set them explicitly with dg-lto-options.

The solution is to remove the explicit -mfloat-abi=softfp and instead add an effective target check
for arm_neon_ok_no_float_abi that makes sure we only run this test if -mfpu=neon is enough to get NEON
without any -mfloat-abi options. In fact, this is what the comment above check_effective_target_arm_neon_ok_no_float_abi_nocache
recommends for lto tests.

That way on my hardfloat toolchain the test doesn't try to link the softfp binary against a hard-float runtime/test glue
and all is good. I've tested that the test is appropriately skipped when testing a --with-float=soft toolchain.

Committing to trunk (as the patch only touches arm options)

Thanks,
Kyrill

2018-01-24  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>

    * gcc.dg/lto/20110201-1_0.c: Remove explicit -mfloat-abi=softfp
    option.  Add arm_neon_ok_no_float_abi check.

diff --git a/gcc/testsuite/gcc.dg/lto/20110201-1_0.c b/gcc/testsuite/gcc.dg/lto/20110201-1_0.c
index 2144f0714804ea1003d58f37ca5d16ced722a3a7..871a49fe1897511e39827b96c7c57931d689ce92 100644
--- a/gcc/testsuite/gcc.dg/lto/20110201-1_0.c
+++ b/gcc/testsuite/gcc.dg/lto/20110201-1_0.c
@@ -1,6 +1,7 @@
 /* { dg-lto-do run } */
 /* { dg-lto-options { { -O0 -flto -fno-math-errno } } } */
-/* { dg-lto-options { "-O0 -flto -fno-math-errno -mfloat-abi=softfp -mfpu=neon-vfpv4" } { target arm*-*-* } } */
+/* { dg-lto-options { "-O0 -flto -fno-math-errno -mfpu=neon-vfpv4" } { target arm*-*-* } } */
+/* { dg-require-effective-target arm_neon_ok_no_float_abi { target arm*-*-* } } */
 /* { dg-require-linker-plugin "" } */
 /* { dg-require-effective-target sqrt_insn } */