Sergei Trofimovich authored Mar 20, 2019 and Ben Gamari committed Jun 24, 2019

On powerpc32 64-bit comparison code generated dangling
target labels. This caused ghc build failure as:

    $ ./configure --target=powerpc-unknown-linux-gnu && make
    ...
    SCCs aren't in reverse dependent order
    bad blockId n3U

This happened because condIntCode' in PPC codegen generated
label name but did not place the label into `cmp_lo` code block.

The change adds the `cmp_lo` label into the case of negative
comparison.

Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
(cherry picked from commit 973077ac)