[glibc/azanella/clang] support: Suppress clang warning on tst-timespec

[Adhemerval Zanella <azanella@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=a28664caff3ecdecdc3ea1ed586f2f866318a506

commit a28664caff3ecdecdc3ea1ed586f2f866318a506
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date:   Fri Mar 25 11:26:46 2022 -0300

    support: Suppress clang warning on tst-timespec
    
    clang warns that converting from TIME_T_MAX to double (upper_bound)
    loses precision (from 9223372036854775807 to 9223372036854775808):
    
      tst-timespec.c:290:19: error: implicit conversion from 'time_t' (aka
      'long') to 'double' changes value from 9223372036854775807 to
      9223372036854775808 [-Werror,-Wimplicit-const-int-float-conversion]
         .upper_bound = TIME_T_MAX, .lower_bound = 1, .result = 1,
                        ^~~~~~~~~~
      tst-timespec.c:48:20: note: expanded from macro 'TIME_T_MAX'
      #define TIME_T_MAX TYPE_MAXIMUM (time_t)
                         ^~~~~~~~~~~~~~~~~~~~~
      ../include/intprops.h:57:4: note: expanded from macro 'TYPE_MAXIMUM'
        ((t) (! TYPE_SIGNED (t)
      \
         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    
    It does not matter for the test.
    
    Checked on x86_64-linux-gnu.

Diff:
---
 support/tst-timespec.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/support/tst-timespec.c b/support/tst-timespec.c
index 66fc42c03d..d622e741ec 100644
--- a/support/tst-timespec.c
+++ b/support/tst-timespec.c
@@ -20,6 +20,7 @@
 #include <support/check.h>
 #include <limits.h>
 #include <intprops.h>
+#include <libc-diag.h>
 
 #define TIMESPEC_HZ 1000000000
 
@@ -179,6 +180,11 @@ struct timespec_norm_test_case norm_cases[] = {
   }
 };
 
+/* clang warns that converting from TIME_T_MAX to double (upper_bound)
+   loses precision (from 9223372036854775807 to 9223372036854775808).
+   It does not matter in tests below.  */
+DIAG_PUSH_NEEDS_COMMENT_CLANG;
+DIAG_IGNORE_NEEDS_COMMENT_CLANG (13, "-Wimplicit-const-int-float-conversion");
 /* Test cases for timespec_check_in_range  */
 struct timespec_test_case check_cases[] = {
   /* 0 - In range  */
@@ -290,6 +296,7 @@ struct timespec_test_case check_cases[] = {
    .upper_bound = TIME_T_MAX, .lower_bound = 1, .result = 1,
   },
 };
+DIAG_POP_NEEDS_COMMENT_CLANG;
 
 static int
 do_test (void)