[Git][ghc/ghc][wip/ncg-simd] 12 commits: Add vector shuffle primops

sheaf (@sheaf) gitlab at gitlab.haskell.org
Wed Sep 25 23:43:33 UTC 2024



sheaf pushed to branch wip/ncg-simd at Glasgow Haskell Compiler / GHC


Commits:
42491d52 by sheaf at 2024-09-26T01:43:24+02:00
Add vector shuffle primops

This adds vector shuffle primops, such as

```
shuffleFloatX4# :: FloatX4# -> FloatX4# -> (# Int#, Int#, Int#, Int# #) -> FloatX4#
```

which shuffle the components of the input two vectors into the output vector.

NB: the indices must be compile time literals, to match the X86 SHUFPD
instruction immediate and the LLVM shufflevector instruction.

These are handled in the X86 NCG and the LLVM backend.

Tested in simd009.

- - - - -
172a8e02 by sheaf at 2024-09-26T01:43:24+02:00
Add Broadcast MachOps

This adds proper MachOps for broadcast instructions, allowing us to
produce better code for broadcasting a value than simply packing that
value (doing many vector insertions in a row).

These are lowered in the X86 NCG and LLVM backends. In the LLVM backend,
it uses the previously introduced shuffle instructions.

- - - - -
056971c0 by sheaf at 2024-09-26T01:43:24+02:00
Fix treatment of signed zero in vector negation

This commit fixes the handling of signed zero in floating-point vector
negation.

A slight hack was introduced to work around the fact that Cmm doesn't
currently have a notion of signed floating point literals
(see get_float_broadcast_value_reg). This can be removed once CmmFloat
can express the value -0.0.

The simd006 test has been updated to use a stricter notion of equality
of floating-point values, which ensure the validity of this change.

- - - - -
efae0744 by sheaf at 2024-09-26T01:43:24+02:00
Add min/max primops

This commit adds min/max primops, such as

  minDouble# :: Double# -> Double# -> Double#
  minFloatX4# :: FloatX4# -> FloatX4# -> FloatX4#
  minWord16X8# :: Word16X8# -> Word16X8# -> Word16X8#

These are supported in:
  - the X86, AArch64 and PowerPC NCGs,
  - the LLVM backend,
  - the WebAssembly and JavaScript backends.

Fixes #25120

- - - - -
cc2f957e by sheaf at 2024-09-26T01:43:24+02:00
Add test for C calls & SIMD vectors

- - - - -
ab9269a0 by sheaf at 2024-09-26T01:43:25+02:00
Add test for #25169

- - - - -
558941ea by sheaf at 2024-09-26T01:43:25+02:00
Fix #25169 using Plan A from the ticket

We now compile certain low-level Cmm functions in the RTS multiple
times, with different levels of vector support. We then dispatch
at runtime in the RTS, based on what instructions are supported.

See Note [realArgRegsCover] in GHC.Cmm.CallConv.

Fixes #25169

-------------------------
Metric Increase:
    T10421
    T12425
    T18730
    T1969
    T9198
-------------------------

- - - - -
9cd13d1c by sheaf at 2024-09-26T01:43:25+02:00
Fix C calls with SIMD vectors

This commit fixes the code generation for C calls, to take into account
the calling convention.

This is particularly tricky on Windows, where all vectors are expected
to be passed by reference. See Note [The Windows X64 C calling convention]
in GHC.CmmToAsm.X86.CodeGen.

- - - - -
151773db by sheaf at 2024-09-26T01:43:25+02:00
X86 CodeGen: refactor getRegister CmmLit

This refactors the code dealing with loading literals into registers,
removing duplication and putting all the code in a single place.
It also changes which XOR instruction is used to place a zero value
into a register, so that we use VPXOR for a 128-bit integer vector
when AVX is supported.

- - - - -
db5ec5e5 by sheaf at 2024-09-26T01:43:25+02:00
X86 genCCall: promote arg before calling evalArgs

The job of evalArgs is to ensure each argument is put into a temporary
register, so that it can then be loaded directly into one of the
argument registers for the C call, without the generated code clobbering
any other register used for argument passing.

However, if we promote arguments after calling evalArgs, there is the
possibility that the code used for the promotion will clobber a register,
defeating the work of evalArgs.
To avoid this, we first promote arguments, and only then call evalArgs.

- - - - -
ace43c6f by sheaf at 2024-09-26T01:43:25+02:00
X86 genCCall64: simplify loadArg code

This commit simplifies the argument loading code by making the
assumption that it is safe to directly load the argument into register,
because doing so will not clobber any previous assignments.

This assumption is borne from the use of 'evalArgs', which evaluates
any arguments which might necessitate non-trivial code generation into
separate temporary registers.

- - - - -
20026067 by sheaf at 2024-09-26T01:43:25+02:00
LLVM: propagate GlobalRegUse information

This commit ensures we keep track of how any particular global register
is being used in the LLVM backend. This informs the LLVM type
annotations, and avoids type mismatches of the following form:

  argument is not of expected type '<2 x double>'
    call ccc <2 x double> (<2 x double>)
      (<4 x i32> arg)

- - - - -


30 changed files:

- compiler/GHC/Builtin/primops.txt.pp
- compiler/GHC/ByteCode/Asm.hs
- compiler/GHC/Cmm/CallConv.hs
- compiler/GHC/Cmm/Lexer.x
- compiler/GHC/Cmm/MachOp.hs
- compiler/GHC/Cmm/Opt.hs
- compiler/GHC/Cmm/Parser.y
- compiler/GHC/Cmm/Reg.hs
- compiler/GHC/CmmToAsm/AArch64/CodeGen.hs
- compiler/GHC/CmmToAsm/AArch64/Instr.hs
- compiler/GHC/CmmToAsm/AArch64/Ppr.hs
- compiler/GHC/CmmToAsm/Format.hs
- compiler/GHC/CmmToAsm/PPC/CodeGen.hs
- compiler/GHC/CmmToAsm/PPC/Instr.hs
- compiler/GHC/CmmToAsm/PPC/Ppr.hs
- compiler/GHC/CmmToAsm/Wasm/Asm.hs
- compiler/GHC/CmmToAsm/Wasm/FromCmm.hs
- compiler/GHC/CmmToAsm/Wasm/Types.hs
- compiler/GHC/CmmToAsm/X86/CodeGen.hs
- compiler/GHC/CmmToAsm/X86/Instr.hs
- compiler/GHC/CmmToAsm/X86/Ppr.hs
- compiler/GHC/CmmToC.hs
- compiler/GHC/CmmToLlvm.hs
- compiler/GHC/CmmToLlvm/Base.hs
- compiler/GHC/CmmToLlvm/CodeGen.hs
- compiler/GHC/CmmToLlvm/Ppr.hs
- compiler/GHC/CmmToLlvm/Regs.hs
- compiler/GHC/JS/Make.hs
- compiler/GHC/Llvm/Ppr.hs
- compiler/GHC/Llvm/Syntax.hs


The diff was not included because it is too large.


View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/1df6d2247e43ff87049c3822512b40c61b4f4076...2002606738f327260632402561189a308098da1f

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