Sanjay Patel de1d5d3675 [InstCombine] canonicalize funnel shift constant shift amount to be modulo bitwidth ...

The shift argument is defined to be modulo the bitwidth, so if that argument
is a constant, we can always reduce the constant to its minimal form to allow
better CSE and other follow-on transforms.

We need to be careful to ignore constant expressions here, or we will likely
infinite loop. I'm adding a general vector constant query for that case.

Differential Revision: https://reviews.llvm.org/D59374

llvm-svn: 356192

2019-03-14 19:22:08 +00:00

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