[PATCH] D75543: [ConstantFolding] Always return something from ConstantFoldConstant

[Nikita Popov via Phabricator via llvm-commits]

nikic created this revision.
nikic added reviewers: efriedma, spatel, lebedev.ri.
Herald added subscribers: llvm-commits, jholewinski.
Herald added a project: LLVM.

Spin-off from D75407 <https://reviews.llvm.org/D75407>. As described there, ConstantFoldConstant() currently returns null for non-ConstantExpr/ConstantVector inputs, but otherwise always returns non-null, independently of whether any folding has happened or not.

This is confusing and makes consumer code more complicated. I would expect either that ConstantFoldConstant() returns only if it actually folded something, or that it always returns non-null. I'm going to the latter possibility here, which appears to be more useful considering existing usage.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D75543

Files:
  include/llvm/Analysis/ConstantFolding.h
  include/llvm/Analysis/TargetFolder.h
  lib/Analysis/ConstantFolding.cpp
  lib/Analysis/InstructionSimplify.cpp
  lib/Analysis/Lint.cpp
  lib/CodeGen/AsmPrinter/AsmPrinter.cpp
  lib/Target/NVPTX/NVPTXAsmPrinter.cpp
  lib/Transforms/AggressiveInstCombine/TruncInstCombine.cpp
  lib/Transforms/IPO/GlobalOpt.cpp
  lib/Transforms/InstCombine/InstCombineCasts.cpp
  lib/Transforms/InstCombine/InstCombineShifts.cpp
  lib/Transforms/InstCombine/InstructionCombining.cpp
  lib/Transforms/Utils/Evaluator.cpp
  lib/Transforms/Utils/VNCoercion.cpp

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