[PATCH] D98906: [X86] Improve lowering of unrolled inline-asm probing

[Simonas Kazlauskas via Phabricator via llvm-commits]

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nagisa retitled this revision from "[x86] Improve lowering of unrolled inline-asm probing" to "[X86] Improve lowering of unrolled inline-asm probing".
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update tests to not scrub away stack pointers


nagisa added a comment.

rebase on top of tests in D98909 <https://reviews.llvm.org/D98909>


nagisa added a comment.

restore the code that handled overaligned allocs


This new implementation emits instructions such as these:

  movb $0, -4096(%rsp)

which is both faster and smaller than pairs of

  sub $4096, %rsp
  movq $0, (%rsp)

This implementation also trivially preserves the preciseness of the
uwtables during the preamble by not modifying the stack pointer in the
first place.

Depends on D98909 <https://reviews.llvm.org/D98909>


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D98906

Files:
  llvm/lib/Target/X86/X86FrameLowering.cpp
  llvm/test/CodeGen/X86/stack-clash-medium-natural-probes-mutliple-objects.ll
  llvm/test/CodeGen/X86/stack-clash-medium-natural-probes.ll
  llvm/test/CodeGen/X86/stack-clash-medium.ll
  llvm/test/CodeGen/X86/stack-clash-small-alloc-medium-align.ll
  llvm/test/CodeGen/X86/stack-clash-unknown-call.ll

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