[PATCH] D93571: [TableGen][ARM][X86] Detect combining IntrReadMem and IntrWriteMem.

[Robert Cox via Phabricator via llvm-commits]

rcox2 added a comment.

Hi Craig Topper,
I noticed a regression after this change set hit our repository at Intel. The code in llvm/lib/Transforms/IPO/FunctionAttrs.cpp has a function checkFunctionMemoryAccess() that is not checking for intrinsics which may have side effects. This causes the inliner to remove a function as trivially dead when it only has a ldmxcsr instruction and some setup and shutdown code. I could change the line:

  if (!AliasAnalysis::onlyAccessesArgPointees(MRB))

to

  if (!AliasAnalysis::onlyAccessesArgPointees(MRB) || I->mayHaveSideEffects()) {

but I do have some concern whether this will be overly conservative. 
Any thoughts?

- Robert Cox from Intel (rcox2)


Repository:
  rG LLVM Github Monorepo

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https://reviews.llvm.org/D93571