[PATCH] D84479: [X86] Detect if EFLAGs is live across XBEGIN pseudo instruction. Add it as livein to the basic blocks created when expanding the pseudo

[Ivan Baev via Phabricator via llvm-commits]

ivanbaev added a comment.

Yes, check for mi.killsRegister(X86::EFLAGS)) before a def (in backward order).
The instructions in mainMBB and fallBB during xbegin() expansion do not deal with EFLAGS. If a subsequent pass makes changes in mainMBB and fallBB that might impact the liveness of EFLAGS, that pass should make proper updates. Having

  mainMBB->addLiveIn(X86::EFLAGS);
  fallMBB->addLiveIn(X86::EFLAGS);

is good too.


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  https://reviews.llvm.org/D84479/new/

https://reviews.llvm.org/D84479