Repost: [PATCH] Fix long double tests when default long double is not IBM.
Bill Schmidt
wschmidt@linux.ibm.com
Wed Jul 14 16:11:29 GMT 2021
Hi Mike,
On 7/7/21 2:58 PM, Michael Meissner wrote:
> [PATCH] Fix long double tests when default long double is not IBM.
>
> This patch adds 3 more selections to target-supports.exp to see if we can force
> the compiler to use a particular long double format (IEEE 128-bit, IBM extended
> double, 64-bit), and the library support will track the changes for the long
> double. This is needed because two of the tests in the test suite use long
> double, and they are actually testing IBM extended double.
>
> This patch also forces the two tests that explicitly require long double
> to use the IBM double-double encoding to explicitly run the test. This
> requires GLIBC 2.32 or greater in order to do the switch.
>
> I have run tests on a little endian power9 system with 3 compilers. There were
> no regressions with these patches, and the two tests in the following patches
> now work if the default long double is not IBM 128-bit:
>
> * One compiler used the default IBM 128-bit format;
> * One compiler used the IEEE 128-bit format; (and)
> * One compiler used 64-bit long doubles.
>
> I have also tested compilers on a big endian power8 system with a compiler
> defaulting to power8 code generation and another with the default cpu
> set. There were no regressions.
>
> Can I check this patch into the master branch?
>
> 2021-07-07 Michael Meissner <meissner@linux.ibm.com>
>
> gcc/testsuite/
> PR target/70117
> * gcc.target/powerpc/pr70117.c: Force the long double type to use
> the IBM 128-bit format.
> * c-c++-common/dfp/convert-bfp-11.c: Force using IBM 128-bit long
> double. Remove check for 64-bit long double.
> * lib/target-supports.exp
> (add_options_for_ppc_long_double_override_ibm128): New function.
> (check_effective_target_ppc_long_double_override_ibm128): New
> function.
> (add_options_for_ppc_long_double_override_ieee128): New function.
> (check_effective_target_ppc_long_double_override_ieee128): New
> function.
> (add_options_for_ppc_long_double_override_64bit): New function.
> (check_effective_target_ppc_long_double_override_64bit): New
> function.
> ---
> .../c-c++-common/dfp/convert-bfp-11.c | 18 +--
> gcc/testsuite/gcc.target/powerpc/pr70117.c | 6 +-
> gcc/testsuite/lib/target-supports.exp | 107 ++++++++++++++++++
> 3 files changed, 121 insertions(+), 10 deletions(-)
>
> diff --git a/gcc/testsuite/c-c++-common/dfp/convert-bfp-11.c b/gcc/testsuite/c-c++-common/dfp/convert-bfp-11.c
> index 95c433d2c24..35da07d1fa4 100644
> --- a/gcc/testsuite/c-c++-common/dfp/convert-bfp-11.c
> +++ b/gcc/testsuite/c-c++-common/dfp/convert-bfp-11.c
> @@ -1,9 +1,14 @@
> -/* { dg-skip-if "" { ! "powerpc*-*-linux*" } } */
I suppose since the compile to check this in the effective target check
is cached, this doesn't hurt much. Ok.
> +/* { dg-require-effective-target dfp } */
> +/* { dg-require-effective-target ppc_long_double_override_ibm128 } */
> +/* { dg-add-options ppc_long_double_override_ibm128 } */
>
> -/* Test decimal float conversions to and from IBM 128-bit long double.
> - Checks are skipped at runtime if long double is not 128 bits.
> - Don't force 128-bit long doubles because runtime support depends
> - on glibc. */
> +/* We force the long double type to be IBM 128-bit because the CONVERT_TO_PINF
> + tests will fail if we use IEEE 128-bit floating point. This is due to IEEE
> + 128-bit having a larger exponent range than IBM 128-bit extended double. So
> + tests that would generate an infinity with IBM 128-bit will generate a
> + normal number with IEEE 128-bit. */
> +
> +/* Test decimal float conversions to and from IBM 128-bit long double. */
>
> #include "convert.h"
>
> @@ -36,9 +41,6 @@ CONVERT_TO_PINF (312, tf, sd, 1.6e+308L, d32)
> int
> main ()
> {
> - if (sizeof (long double) != 16)
> - return 0;
> -
> convert_101 ();
> convert_102 ();
>
> diff --git a/gcc/testsuite/gcc.target/powerpc/pr70117.c b/gcc/testsuite/gcc.target/powerpc/pr70117.c
> index 3bbd2c595e0..8a5fad1dee0 100644
> --- a/gcc/testsuite/gcc.target/powerpc/pr70117.c
> +++ b/gcc/testsuite/gcc.target/powerpc/pr70117.c
> @@ -1,5 +1,7 @@
> -/* { dg-do run { target { powerpc*-*-linux* powerpc*-*-darwin* powerpc*-*-aix* rs6000-*-* } } } */
> -/* { dg-options "-std=c99 -mlong-double-128 -O2" } */
> +/* { dg-do run } */
> +/* { dg-require-effective-target ppc_long_double_override_ibm128 } */
> +/* { dg-options "-std=c99 -O2" } */
> +/* { dg-add-options ppc_long_double_override_ibm128 } */
>
> #include <float.h>
>
> diff --git a/gcc/testsuite/lib/target-supports.exp b/gcc/testsuite/lib/target-supports.exp
> index 789723fb287..0a392cb0fd5 100644
> --- a/gcc/testsuite/lib/target-supports.exp
> +++ b/gcc/testsuite/lib/target-supports.exp
> @@ -2360,6 +2360,113 @@ proc check_effective_target_ppc_ieee128_ok { } {
> }]
> }
>
> +# Check if we can explicitly override the long double format to use the IBM
> +# 128-bit extended double format, and GLIBC supports doing this override by
> +# switching the sprintf to handle IBM 128-bit long double.
> +
> +proc add_options_for_ppc_long_double_override_ibm128 { flags } {
> + if { [istarget powerpc*-*-*] } {
> + return "$flags -mlong-double-128 -Wno-psabi -mabi=ibmlongdouble"
Just for my edification, can you remind me why we need -Wno-psabi?
What warning are we disabling? Same question for ieee variant.
LGTM in any event. Recommend approval by maintainers...
Thanks!
Bill
> + }
> + return "$flags"
> +}
> +
> +proc check_effective_target_ppc_long_double_override_ibm128 { } {
> + return [check_runtime_nocache ppc_long_double_override_ibm128 {
> + #include <string.h>
> + #include <stdio.h>
> + volatile __ibm128 a = (__ibm128) 3.0;
> + volatile long double one = 1.0L;
> + volatile long double two = 2.0L;
> + volatile long double b;
> + char buffer[20];
> + int main()
> + {
> + #if !defined(_ARCH_PPC) || !defined(__LONG_DOUBLE_IBM128__)
> + return 1;
> + #else
> + b = one + two;
> + if (memcmp ((void *)&a, (void *)&b, sizeof (long double)) != 0)
> + return 1;
> + sprintf (buffer, "%lg", b);
> + return strcmp (buffer, "3") != 0;
> + #endif
> + }
> + } [add_options_for_ppc_long_double_override_ibm128 ""]]
> +}
> +
> +# Check if we can explicitly override the long double format to use the IEEE
> +# 128-bit format, and GLIBC supports doing this override by switching the
> +# sprintf to handle IEEE 128-bit long double.
> +
> +proc add_options_for_ppc_long_double_override_ieee128 { flags } {
> + if { [istarget powerpc*-*-*] } {
> + return "$flags -mlong-double-128 -Wno-psabi -mabi=ieeelongdouble"
> + }
> + return "$flags"
> +}
> +
> +proc check_effective_target_ppc_long_double_override_ieee128 { } {
> + return [check_runtime_nocache ppc_long_double_override_ieee128 {
> + #include <string.h>
> + #include <stdio.h>
> + volatile _Float128 a = 3.0f128;
> + volatile long double one = 1.0L;
> + volatile long double two = 2.0L;
> + volatile long double b;
> + char buffer[20];
> + int main()
> + {
> + #if !defined(_ARCH_PPC) || !defined(__LONG_DOUBLE_IEEE128__)
> + return 1;
> + #else
> + b = one + two;
> + if (memcmp ((void *)&a, (void *)&b, sizeof (long double)) != 0)
> + return 1;
> + sprintf (buffer, "%lg", b);
> + return strcmp (buffer, "3") != 0;
> + #endif
> + }
> + } [add_options_for_ppc_long_double_override_ieee128 ""]]
> +}
> +
> +# Check if we can explicitly override the long double format to use 64-bit
> +# floating point, and GLIBC supports doing this override by switching the
> +# sprintf to handle 64-bit long double.
> +
> +proc add_options_for_ppc_long_double_override_64bit { flags } {
> + if { [istarget powerpc*-*-*] } {
> + return "$flags -mlong-double-64"
> + }
> + return "$flags"
> +}
> +
> +proc check_effective_target_ppc_long_double_override_64bit { } {
> + return [check_runtime_nocache ppc_long_double_override_64bit {
> + #include <string.h>
> + #include <stdio.h>
> + volatile double a = 3.0;
> + volatile long double one = 1.0L;
> + volatile long double two = 2.0L;
> + volatile long double b;
> + char buffer[20];
> + int main()
> + {
> + #if !defined(_ARCH_PPC) || defined(__LONG_DOUBLE_128__)
> + return 1;
> + #else
> + if (sizeof (long double) != sizeof (double))
> + return 1;
> + b = one + two;
> + if (memcmp ((void *)&a, (void *)&b, sizeof (long double)) != 0)
> + return 1;
> + sprintf (buffer, "%lg", b);
> + return strcmp (buffer, "3") != 0;
> + #endif
> + }
> + } [add_options_for_ppc_long_double_override_64bit ""]]
> +}
> +
> # Return 1 if the target supports executing VSX instructions, 0
> # otherwise. Cache the result.
>
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