This was reverted due to performance regressions in ARM benchmarks,
which have since been addressed by D101196 (SCEV analysis improvement)
and D101778 (CGP reverse transform).
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The single-use case is handled implicity by converting the icmp
into a mask check first. When comparing with zero in particular,
we don't need the one-use restriction, as we only produce a single
icmp.
https://alive2.llvm.org/ce/z/MSixcmhttps://alive2.llvm.org/ce/z/GwpG0M
This reverts commit 9423f78240a216e3f38b394a41fe3427dee22c26.
A performance regression with this patch has been reported at
https://reviews.llvm.org/rG9423f78240a2#990953. Reverting for now.
