Fix additional GCC 13 build issue (#2222188)

Resolves: #2222188

glibc-rh2222188-6.patch

@@ -0,0 +1,36 @@
+commit c8126360dfa98024cc40bce915e126309993cdf9
+Author: Joseph Myers <joseph@codesourcery.com>
+Date:   Mon Aug 23 16:18:42 2021 +0000
+
+    Fix iconv build with GCC mainline
+    
+    Current GCC mainline produces -Wstringop-overflow errors building some
+    iconv converters, as discussed at
+    <https://gcc.gnu.org/pipermail/gcc/2021-July/236943.html>.  Add an
+    __builtin_unreachable call as suggested so that GCC can see the case
+    that would involve a buffer overflow is unreachable; because the
+    unreachability depends on valid conversion state being passed into the
+    function from previous conversion steps, it's not something the
+    compiler can reasonably deduce on its own.
+    
+    Tested with build-many-glibcs.py that, together with
+    <https://sourceware.org/pipermail/libc-alpha/2021-August/130244.html>,
+    it restores the glibc build for powerpc-linux-gnu.
+
+diff --git a/iconv/loop.c b/iconv/loop.c
+index 062cc1b868c1efa5..560a5f6394e8faf6 100644
+--- a/iconv/loop.c
++++ b/iconv/loop.c
+@@ -436,6 +436,12 @@ SINGLE(LOOPFCT) (struct __gconv_step *step,
+     return __GCONV_FULL_OUTPUT;
+ 
+   /*  Now add characters from the normal input buffer.  */
++  if (inlen >= MAX_NEEDED_INPUT)
++    /* Avoid a -Wstringop-overflow= warning when this loop is
++       unrolled.  The compiler cannot otherwise see that this is
++       unreachable because it depends on (state->__count & 7) not
++       being too large after a previous conversion step.  */
++    __builtin_unreachable ();
+   do
+     bytebuf[inlen++] = *inptr++;
+   while (inlen < MAX_NEEDED_INPUT && inptr < inend);

glibc.spec

@@ -155,7 +155,7 @@ end \
 Summary: The GNU libc libraries
 Name: glibc
 Version: %{glibcversion}
-Release: 80%{?dist}
+Release: 81%{?dist}
 
 # In general, GPLv2+ is used by programs, LGPLv2+ is used for
 # libraries.
@@ -745,6 +745,7 @@ Patch504: glibc-rh2213907-5.patch
 Patch505: glibc-rh2213907-6.patch
 Patch506: glibc-rh2166710-2.patch
 Patch507: glibc-rh2166710-3.patch
+Patch508: glibc-rh2222188-6.patch
 
 ##############################################################################
 # Continued list of core "glibc" package information:
@@ -2902,6 +2903,9 @@ update_gconv_modules_cache ()
 %endif
 
 %changelog
+* Mon Aug 14 2023 Florian Weimer <fweimer@redhat.com> - 2.34-81
+- Fix additional GCC 13 build issue (#2222188)
+
 * Fri Aug 11 2023 Florian Weimer <fweimer@redhat.com> - 2.34-80
 - Fix AMD cache size computation for hypervisors, old CPUs (#2166710)