[all-commits] [llvm/llvm-project] 6e5802: [MachineScheduler] Rework dag-maps-huge-region (#2...

[Arthur Eubanks via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 6e58021642834b4646ffea0fb9a2254f46d30173
      https://github.com/llvm/llvm-project/commit/6e58021642834b4646ffea0fb9a2254f46d30173
  Author: Arthur Eubanks <aeubanks at google.com>
  Date:   2026-06-04 (Thu, 04 Jun 2026)

  Changed paths:
    M llvm/include/llvm/CodeGen/ScheduleDAGInstrs.h
    M llvm/lib/CodeGen/ScheduleDAGInstrs.cpp
    A llvm/test/CodeGen/AArch64/dag-maps-huge-region.ll
    M llvm/test/CodeGen/AMDGPU/gfx-callable-return-types.ll
    M llvm/test/CodeGen/AMDGPU/memintrinsic-unroll.ll
    M llvm/test/CodeGen/X86/vector-interleaved-load-i64-stride-8.ll
    M llvm/test/CodeGen/X86/vector-interleaved-store-i64-stride-8.ll

  Log Message:
  -----------
  [MachineScheduler] Rework dag-maps-huge-region (#200945)

For compile time/memory reasons, dag-maps-huge-region is the number of
memory instructions at which we create a barrier and reset maps.
Previously we'd get to dag-maps-huge-region number of instructions, then
add a barrier in the middle of the current set of instructions, and
continue processing the second half of remaining instructions.

With this change, now we simply add a barrier every time we reach
dag-maps-huge-region number of memory instructions, and blow away all
previous instructions.

So now instead of waiting until we get to 1000 memory operations before
creating a barrier for 500 of them, we do it at 500 and do it for all
500.

With this change, -dag-maps-huge-region=500 still has
addChainDependencies() taking up over half of the codegen pipeline in
some cases I looked at, but it's much better than the previous 90%.



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