[PATCH] D71698: [AArch64][SVE] Add intrinsic for non-faulting loads

[Eli Friedman via Phabricator via cfe-commits]

efriedma added inline comments.


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Comment at: llvm/lib/Target/AArch64/SVEInstrFormats.td:5333
+  // We need a layer of indirection because early machine code passes balk at
+  // physical register (i.e. FFR) uses that have no previous definition.
+  let hasSideEffects = 1, hasNoSchedulingInfo = 1, mayLoad = 1 in {
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This is depending on hasSideEffects to preserve the correct ordering with instructions that read/write FFR?  That probably works.  I guess the alternative is to insert an IMPLICIT_DEF of FFR in the entry block of each function.

What are the calling convention rules for FFR?  Is it callee-save?  If not, we might need to do some work to make FFR reads/writes do something sane across calls inserted by the compiler.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D71698/new/

https://reviews.llvm.org/D71698