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[3/3] PowerPC: Force IBM long double for conversion test.

Message ID 20201204040329.GC24930@ibm-toto.the-meissners.org
State New
Headers show
Series Updates for float128 tests | expand

Commit Message

Michael Meissner Dec. 4, 2020, 4:03 a.m. UTC 
PowerPC: Force IBM long double for conversion test.

This patch replaces the following patch:
| Date: Sat, 21 Nov 2020 00:39:53 -0500
| Subject: [PATCH 3/3] PowerPC: Require IBM long double for conversion test.
| Message-ID: <20201121053953.GE17995@ibm-toto.the-meissners.org>
| https://gcc.gnu.org/pipermail/gcc-patches/2020-November/559841.html

The test c-c++-common/dfp/convert-bfp-11.c explicitly expects long double to
use the IBM 128-bit extended double format.  In particular, some of the tests
expect an infinity to be created if decimal values that are converted that are
too large for IBM extended double.  However, the numbers do fit in the range
for IEEE 128-bit format, since it has a larger exponent than the IBM 128-bit
format.  The test fails because an infinity is not generated.

This patch uses the target support option that says we can change the long
double type.  If the long double type uses the IBM format, you can use older
GLIBCs.  If you are using IEEE long doubles, this test will only run if GLIBC
is 2.32 or newer that supports switching the long double format.

I have checked this patch with 3 compilers built on a little endian power9
system, 1 compiler with IBM default long double, 1 compiler with IEEE default
long double, and 1 compiler with 64-bit long double.  This test passes with all
3 compilers.

Can I check this patch into the master branch?

gcc/testsuite/
2020-12-03  Michael Meissner  <meissner@linux.ibm.com>

	* c-c++-common/dfp/convert-bfp-11.c: Force using IBM 128-bit long
	double.  Remove check for 64-bit long double.
---
 .../c-c++-common/dfp/convert-bfp-11.c          | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)
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Patch

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..d19d6aa9220 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*" } } */
+/* { dg-require-effective-target dfp } */
+/* { dg-require-effective-target ppc_long_double_override_ibm } */
+/* { dg-options "-O2 -mlong-double-128 -mabi=ibmlongdouble -Wno-psabi" } */
 
-/* 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 ();