Due to an improvement to name preservation, a lot of InstCombine
tests now show spurious diffs when regenerated.
Rather than regenerating individual files when they get touched,
mass-regenerate all UTC-based InstCombine tests. I have then reset
a number of files showing suspicious diffs where the UTC output
has clearly been manually adjusted. I apologize if I missed
anything in the mass of changes.
If the incoming values of a phi are pointer casts of the same original
value, replace the phi with a single cast. Such redundant phis are
somewhat common after loop-rotate and removing them can avoid some
unnecessary code bloat, e.g. because an iteration of a loop is peeled
off to make the phi invariant. It should also simplify further analysis
on its own.
InstCombine already uses stripPointerCasts in a couple of places and
also simplifies phis based on the incoming values, so the patch should
fit in the existing scope.
The patch causes binary changes in 47 out of 237 benchmarks in
MultiSource/SPEC2000/SPEC2006 with -O3 -flto on X86.
Reviewed By: lebedev.ri
Differential Revision: https://reviews.llvm.org/D98058
