[PATCH] D51085: [Sparc] Add errata workaround pass for GR712RC

[Daniel Cederman via Phabricator via llvm-commits]

dcederman created this revision.
dcederman added reviewers: jyknight, venkatra.
Herald added subscribers: llvm-commits, jfb, jrtc27, fedor.sergeev.

This patch adds a pass that provides workarounds for the errata described in the technical notes GRLIB-TN-0009, GRLIB-TN-0011, GRLIB-TN-0012, and GRLIB-TN-0013, that are applicable to the GR712RC. The documents are available for download from here:

https://www.gaisler.com/index.php/information/app-tech-notes

The pass will detect certain sensitive instruction sequences and prevent them from occurring by inserting NOP instructions. Below is an overview of each of the workarounds. A similar implementation is available in GCC.

GRLIB-TN-0009:

- Insert NOPs to prevent the sequence (stb/sth/st/stf) -> (single non-store/load instruction) -> (any store)

- Insert NOPs to prevent the sequence (std/stdf) -> (any store)

GRLIB-TN-0011:

- Insert .p2align 4 before atomic instructions (swap and casa).

GRLIB-TN-0012:

- Place a NOP at the branch target of an integer branch if it is a floating-point operation or a floating-point branch.

GRLIB-TN-0013:

- Prevent (div/sqrt) instructions in the delay slot.

- Insert NOPs to prevent the sequence (div/sqrt) -> (two or three floating point operations or loads) -> (div/sqrt).

- Do not insert NOPs if any of the floating point operations have a dependency on the destination register of the first (div/sqrt).

- Do not insert NOPs if one of the floating point operations is a (div/sqrt).

- Insert NOPs to prevent (div/sqrt) followed by a branch.


Repository:
  rL LLVM

https://reviews.llvm.org/D51085

Files:
  lib/Target/Sparc/DelaySlotFiller.cpp
  lib/Target/Sparc/LeonFeatures.td
  lib/Target/Sparc/LeonPasses.cpp
  lib/Target/Sparc/Sparc.h
  lib/Target/Sparc/Sparc.td
  lib/Target/Sparc/SparcAsmPrinter.cpp
  lib/Target/Sparc/SparcSubtarget.cpp
  lib/Target/Sparc/SparcSubtarget.h
  lib/Target/Sparc/SparcTargetMachine.cpp
  test/CodeGen/SPARC/tn0009.mir
  test/CodeGen/SPARC/tn0011.ll
  test/CodeGen/SPARC/tn0012.mir
  test/CodeGen/SPARC/tn0013.mir

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