[PATCH] D142084: [RFC][X86][MemFold] Upgrade the mechanism of auto-generated Memory Folding Table

Mon Feb 13 21:08:52 PST 2023

craig.topper added inline comments.

================
Comment at: llvm/lib/Target/X86/X86MemFoldTables.inc:614
   {X86::UCOMISSrr_Int, X86::UCOMISSrm_Int, TB_NO_REVERSE},
+  {X86::UD1Lr, X86::UD1Lm, 0},
+  {X86::UD1Qr, X86::UD1Qm, 0},
----------------
These aren't real load instructions. It doesn't really make sense for them to be in the table. Folding the load would make the load not happen. That would be incorrect for volatile.

================
Comment at: llvm/lib/Target/X86/X86MemFoldTables.inc:4009
   {X86::VMINSSZrr_Intkz, X86::VMINSSZrm_Intkz, TB_NO_REVERSE},
-  {X86::VMOVAPDZ128rrk, X86::VMOVAPDZ128rmk, TB_NO_REVERSE|TB_ALIGN_16},
-  {X86::VMOVAPDZ256rrk, X86::VMOVAPDZ256rmk, TB_NO_REVERSE|TB_ALIGN_32},
-  {X86::VMOVAPDZrrk, X86::VMOVAPDZrmk, TB_NO_REVERSE|TB_ALIGN_64},
-  {X86::VMOVAPSZ128rrk, X86::VMOVAPSZ128rmk, TB_NO_REVERSE|TB_ALIGN_16},
-  {X86::VMOVAPSZ256rrk, X86::VMOVAPSZ256rmk, TB_NO_REVERSE|TB_ALIGN_32},
-  {X86::VMOVAPSZrrk, X86::VMOVAPSZrmk, TB_NO_REVERSE|TB_ALIGN_64},
+  {X86::VMOVAPDZ128rrk, X86::VMOVAPDZ128rmk, TB_ALIGN_16},
+  {X86::VMOVAPDZ256rrk, X86::VMOVAPDZ256rmk, TB_ALIGN_32},
----------------
Would this allow unfolding a VMOVAPDZ128rmk to VMOVAPDZ128rrk + VMOVAPDZ128rm? That would be a bug.

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D142084/new/

https://reviews.llvm.org/D142084