[glibc/main] math: Suppress -O0 warnings for soft-fp fsqrt [BZ #19444]

[Adhemerval Zanella <azanella@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=30546ac2d1d64adff07d317e3041ec0fc6e32f6d

commit 30546ac2d1d64adff07d317e3041ec0fc6e32f6d
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date:   Thu Dec 29 09:58:02 2022 -0300

    math: Suppress -O0 warnings for soft-fp fsqrt [BZ #19444]
    
    The patch suppress the same warnings from 87c266d758d29e52bfb717f90,
    that shows issues for microblaze, mips soft-fp, nios2, and or1k.
    Reviewed-by: Carlos O'Donell <carlos@redhat.com>

Diff:
---
 sysdeps/ieee754/soft-fp/s_fsqrt.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/sysdeps/ieee754/soft-fp/s_fsqrt.c b/sysdeps/ieee754/soft-fp/s_fsqrt.c
index 68f5146976..9fd3c839d4 100644
--- a/sysdeps/ieee754/soft-fp/s_fsqrt.c
+++ b/sysdeps/ieee754/soft-fp/s_fsqrt.c
@@ -25,6 +25,15 @@
 #undef fsqrtl
 
 #include <math-narrow.h>
+#include <libc-diag.h>
+/* R_f[01] are not set in cases where they are not used in packing,
+   but the compiler does not see that they are set in all cases where
+   they are used, resulting in warnings that they may be used
+   uninitialized.  The location of the warning differs in different
+   versions of GCC, it may be where R is defined using a macro or it
+   may be where the macro is defined.  This happens only with -O1.  */
+DIAG_PUSH_NEEDS_COMMENT;
+DIAG_IGNORE_NEEDS_COMMENT (8, "-Wmaybe-uninitialized");
 #include <soft-fp.h>
 #include <single.h>
 #include <double.h>
@@ -51,4 +60,6 @@ __fsqrt (double x)
   CHECK_NARROW_SQRT (ret, x);
   return ret;
 }
+DIAG_POP_NEEDS_COMMENT;
+
 libm_alias_float_double (sqrt)