0.25.16

Added

• futhark test: --no-terminal now prints status messages even when
  no failures occur.

• futhark test no longer runs structure tests by default. Pass
  -s to run them.

• Rewritten array layout optimisation pass by Bjarke Pedersen and
  Oscar Nelin. Minor speedup for some programs, but is more
  importantly a principled foundation for further improvements.

• Better error message when exceeding shared memory limits.

• Better dead code removal for the GPU representation (minor impact on
  some programs).

Fixed

• Bugs related to deduplication of array payloads in sum types.
  Unfortunately, fixed by just not deduplicating in those cases.

• Frontend bug related to turning size expressions into variables
  (#2136).

• Another exotic monomorphisation bug.

0.25.15

Added

• Incremental Flattening generates fewer redundant code versions.

• Better simplification of slices. (#2125)

Fixed

• Ignore type suffixes when unifying expressions (#2124).

• In the C API, opaque types that correspond to an array of an opaque
  type are now once again named futhark_opaque_arr_....

• cuda backend did not correctly profile CPU-to-GPU scalar copies.

0.25.14

Added

• The prelude definition of filter is now more memory efficient,
  particularly when the output is much smaller than the input. (#2109)

• New configuration for GPU backends:
  futhark_context_config_set_unified_memory, also available on
  executables as --unified-memory.

• The "raw" API functions now do something potentially useful, but are
  still considered experimental.

• futhark --version now reports GHC version.

Fixed

• Incorrect type checking of let-bound sizes occurring multiple times
  in pattern. (#2103).

• A concatenation simplification would sometimes mess up sizes.
  (#2104)

• Bug related to monomorphisation of polymorphic local functions
  (#2106).

• Rare crash in short circuiting.

• Referencing an unbound type parameter could crash the type checker
  (#2113, #2114).

• Futhark now works with GHC 9.8 (#2105).

0.25.13

Added

• Incremental flattening of map-scan compositions with nested
  parallelism (similar to the logic for map-reduce compositions
  that we have had for years).

• futhark script, for running FutharkScript expressions from the
  command line.

• futhark repl now prints out a message when it ignores a breakpoint
  during initialisation. (#2098)

Fixed

• Flattening of scatter with multi-dimensional elements (#2089).

• Some instances of not-actually-irregular allocations were mistakenly
  interpreted as irregular. Fixing this was a dividend of the memory
  representation simplifications of 0.25.12.

• Obscure issue related to expansion of shared memory allocations (#2092).

• A crash in alias checking under some rare circumstances (#2096).

• Mishandling of existential sizes for top level constants. (#2099)

• Compiler crash when generating code for copying nothing at all. (#2100)

0.25.12

Added

• f16.copysign, f32.copysign, f64.copysign.

• Trailing commas are now allowed for all syntactical elements that
  involve comma-separation. (#2068)

• The C API now allows destruction and construction of sum types (with
  some caveats). (#2074)

• An overall reduction in memory copies, through simplifying the
  internal representation.

Fixed

• C API would define distinct entry point types for Futhark types that
  differed only in naming of sizes (#2080).

• == and != on sum types with array payloads. Constructing them is
  now a bit slower, though. (#2081)

• Somewhat obscure simplification error caused by neglecting to update
  metadata when removing dead scatter outputs.

• Compiler crash due to the type checker forgetting to respect the
  explicitly ascribed non-consuming diet of loop parameters (#2067).

• Size inference did incomplete level/scope checking, which could
  result in circular sizes, which usually manifested as the type
  checker going into an infinite loop (#2073).

• The OpenCL backend now more gracefully handles lack of platform.

0.25.11

Added

• New prelude function: manifest. For doing subtle things to memory.

• The GPU backends now handle up to 20 operators in a single fused
  reduction.

• CUDA/HIP terminology for GPU concepts (e.g. "thread block") is now
  used in all public interfaces. The OpenCL names are still supported
  for backwards compatibility.

• More fusion across array slicing.

Fixed

• Compatibility with CUDA versions prior than 12.

0.25.10

Added

• Faster non-commutative reductions in the GPU backends. Work by
  Anders Holst and Christian Påbøl Jacobsen.

Fixed

• Interpreter crash for certain complicated size expressions involving
  internal bindings (#2053).

• Incorrect type checking of let binding with explicit size
  quantification, where size appears in type of body (#2048).

• GPU code generation for non-commutative non-segmented reductions
  with array operands (#2051).

• Histogram with non-vectorised reduction operators (#2056). (But it
  is probably not a good idea to write such programs.)

• Futhark's LSP server should work better with Eglot.

• Incorrect copy removal inside histograms could cause compiler error
  (#2058).

• CUDA backend now correctly queries for available shared memory,
  which affects performance (hopefully positively).

• futhark literate now switches to the directory containing the
  .fut file before executing its contents. This fixes accessing
  files through relative paths.

0.25.9

Added

• The cuda and hip backends now generate faster code for scans
  that have been fused with maps that internally produce arrays.
  Work by Anders Holst and Christian Påbøl Jacobsen.

• f16.ldexp, f32.ldexp, f64.ldexp, corresponding to the
  functions in the C math library.

Fixed

• Incorrect data dependency information for scatter and vjp could
  cause invalid simplification.

• Barrier divergence in certain complicated kernels that contain both
  bounds checks and intragroup scans.

0.25.8

Added

• FutharkScript now has a $loadbytes builtin function for reading
  arbitrary bytes into Futhark programs.

• futhark profile can now process reports produced by the C API
  function futhark_context_report().

• futhark profile now also produces a timeline of events.

Fixed

• futhark literate no longer fails if the final line is a directive
  without a trailing newline.

• Parser now allows arbitrary patterns in function parameters and
  let bindings, although the type checker will reject any that are
  refutable (#2017).

• Avoid generating invalid code in cases where deduplicated sum types
  are exposed through entry points (#1960).

• A bug in data dependency analysis for histogram operations would
  mistakenly classify some loop parameters as redundant, leaving to
  code being removed.

0.25.7

Added

• futhark autotune now supports hip backend.

• Better parallelisation of scatter when the target is
  multidimensional (#2035).

Fixed

• Very large iotas now work.

• Lambda lifting in while conditions (#2038).

• Size expressions in local function parameters had an interesting
  interaction with defunctionalisation (#2040).

• The store command in server executables did not properly
  synchronise when storing opaque values, which would lead to
  use-after-free errors.