[PATCH] D115924: [ConstantFolding] Unify handling of load from uniform value

[Nikita Popov via Phabricator via llvm-commits]

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There are a number of places that specially handle loads from a uniform value where all the bits are the same (zero, one, undef, poison), because we a) don't care about the load offset in that case b) it bypasses casts that might not be legal generally but do work with uniform values.

We had multiple implementations of this, with a different set of supported values each time, as well as incomplete type checks in some cases. In particular, this fixes the assertion reported in https://reviews.llvm.org/D114889#3198921, as well as a similar assertion that could be triggered via constant folding.


https://reviews.llvm.org/D115924

Files:
  llvm/include/llvm/Analysis/ConstantFolding.h
  llvm/lib/Analysis/ConstantFolding.cpp
  llvm/lib/Transforms/IPO/GlobalOpt.cpp
  llvm/test/Transforms/GlobalOpt/x86_mmx_load.ll
  llvm/test/Transforms/InstSimplify/ConstProp/loads.ll

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