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Description of problem: The fix for https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68814
is needed in RHEL 7 (GCC 4.8.5) but was discovered after 4.8 went out of service.  This was discovered by a team at Nutanix.


Version-Release number of selected component (if applicable): 4.8.5


How reproducible:

#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>

static uint64_t __attribute__((noinline))
expand_value(uint64_t value)
{

 value &= 0xffffffff;
 value |= value << 32;

 return value;
}

int main(int argc, char **argv)
{

 if (argc > 1) {
   uint64_t v = strtoull(argv[1], NULL, 0);
   printf("%llx -> %llx\n", v, expand_value(v));
 }

 return 0;
}



Steps to Reproduce:
1. Compile the above program with -O2 -S.
2. Verify that the expand_value function compiles to nothing but a "blr" instruction.
3. Correct behavior with the patch is to also generate an rldimi instruction.

Actual results:

See step 2 above.

Expected results:

See step 3 above.

Additional info:  This is a simple fix to change an occurrence of BYTES_BIG_ENDIAN to BITS_BIG_ENDIAN in common code (rtlanal.c).

I verified reproducer from comment #0 contains rldimi instruction when compiled with  -O2 -S for gcc-4.8.5-39.el7.ppc64le and doesn't contain it for gcc-4.8.5-36.el7.ppc64le.

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2019:2167