[all-commits] [llvm/llvm-project] 6f53ae: [X86] Properly chain PROBED_ALLOCA / SEG_ALLOCA (#...

[Sergei Barannikov via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 6f53ae6e613f5f7011c1752b94038114f4e1cc94
      https://github.com/llvm/llvm-project/commit/6f53ae6e613f5f7011c1752b94038114f4e1cc94
  Author: Sergei Barannikov <barannikov88 at gmail.com>
  Date:   2024-11-19 (Tue, 19 Nov 2024)

  Changed paths:
    M llvm/lib/Target/X86/X86ISelLowering.cpp
    M llvm/test/CodeGen/X86/segmented-stacks-dynamic.ll

  Log Message:
  -----------
  [X86] Properly chain PROBED_ALLOCA / SEG_ALLOCA (#116508)

These nodes should appear between CALLSEQ_START / CALLSEQ_END.
Previously, they could be scheduled after CALLSEQ_END because the nodes
didn't update the chain.

The change in a test is due to X86 call frame optimizer pass bailing out
for a particular call when CALLSEQ_START / CALLSEQ_END are not in the
same basic block. This happens because SEG_ALLOCA is expanded into a
sequence of basic blocks early. It didn't bail out before because the
closing CALLSEQ_END was scheduled before SEG_ALLOCA, in the same basic
block as CALLSEQ_START.

While here, simplify creation of these nodes: allocating a virtual
register and copying `Size` into it were unnecessary.



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