[all-commits] [llvm/llvm-project] 6030fe: [llvm-exegesis] Exploring X86::OperandType::OPERAN...

[Roman Lebedev via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 6030fe01f4ee9a65d92effe44749bee11b36d346
      https://github.com/llvm/llvm-project/commit/6030fe01f4ee9a65d92effe44749bee11b36d346
  Author: Roman Lebedev <lebedev.ri at gmail.com>
  Date:   2020-02-12 (Wed, 12 Feb 2020)

  Changed paths:
    A llvm/test/tools/llvm-exegesis/X86/latency-SETCCr-cond-codes-sweep.s
    M llvm/tools/llvm-exegesis/lib/CodeTemplate.h
    M llvm/tools/llvm-exegesis/lib/ParallelSnippetGenerator.cpp
    M llvm/tools/llvm-exegesis/lib/ParallelSnippetGenerator.h
    M llvm/tools/llvm-exegesis/lib/SerialSnippetGenerator.cpp
    M llvm/tools/llvm-exegesis/lib/SerialSnippetGenerator.h
    M llvm/tools/llvm-exegesis/lib/SnippetGenerator.cpp
    M llvm/tools/llvm-exegesis/lib/SnippetGenerator.h
    M llvm/tools/llvm-exegesis/lib/Target.h
    M llvm/tools/llvm-exegesis/lib/X86/Target.cpp
    M llvm/tools/llvm-exegesis/llvm-exegesis.cpp
    M llvm/unittests/tools/llvm-exegesis/CMakeLists.txt
    M llvm/unittests/tools/llvm-exegesis/Mips/SnippetGeneratorTest.cpp
    A llvm/unittests/tools/llvm-exegesis/SnippetGeneratorTest.cpp
    M llvm/unittests/tools/llvm-exegesis/X86/SnippetGeneratorTest.cpp

  Log Message:
  -----------
  [llvm-exegesis] Exploring X86::OperandType::OPERAND_COND_CODE

Summary:
Currently, we only have nice exploration for LEA instruction,
while for the rest, we rely on `randomizeUnsetVariables()`
to sometimes generate something interesting.
While that works, it isn't very reliable in coverage :)

Here, i'm making an assumption that while we may want to explore
multi-instruction configs, we are most interested in the
characteristics of the main instruction we were asked about.

Which we can do, by taking the existing `randomizeMCOperand()`,
and turning it on it's head - instead of relying on it to randomly fill
one of the interesting values, let's pregenerate all the possible interesting
values for the variable, and then generate as much `InstructionTemplate`
combinations of these possible values for variables as needed/possible.

Of course, that requires invasive changes to no longer pass just the
naked `Instruction`, but sometimes partially filled `InstructionTemplate`.

As it can be seen from the test, this allows us to explore
`X86::OperandType::OPERAND_COND_CODE` for instructions
that take such an operand.
I'm hoping this will greatly simplify exploration.

Reviewers: courbet, gchatelet

Reviewed By: gchatelet

Subscribers: orodley, mgorny, sdardis, tschuett, jrtc27, atanasyan, mstojanovic, andreadb, RKSimon, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D74156