[Bug testsuite/63177] Powerpc no-vfa-vect-depend-2.c and no-vfa-vect-depend-3.c failures

[carll at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63177

Carl Love <carll at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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           Assignee|unassigned at gcc dot gnu.org      |carll at gcc dot gnu.org

--- Comment #7 from Carl Love <carll at gcc dot gnu.org> ---
So the bug only occurs if GCC is configured wfor power8 or you also use the
option -mcpu=power8 when compiling the test.  If you configure with or use
-mcpu-power9 then the proper code generation is done.  

Pat Haugen looked at this issue.  It appears that GCC is calling the assembler
with -mpower9 causing the P9 "stxvx" instruction to be generated to store the
data in the correct order.  In the case of power8 the compiler passes -mpower8
to the assembler which uses the "stxvx" extended mnemonic which maps to stxvd2x
which doesn't store the data in the correct order.