bjoernager/rust
bjoernager/rust
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clean up autodiff code/comments

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This commit is contained in:
Manuel Drehwald 2025-02-21 21:47:48 -05:00
parent fe90883ef7
commit f4e2218b13
3 changed files with 6 additions and 12 deletions
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1
compiler/rustc_ast/src/expand/autodiff_attrs.rs
View file

@ -17,7 +17,6 @@ use crate::{Ty, TyKind};
/// functions. The proper solution is to recognize and resolve this DAG of autodiff invocations,
/// as it's already done in the C++ and Julia frontend of Enzyme.
///
/// (FIXME) remove *First variants.
/// Documentation for using [reverse](https://enzyme.mit.edu/rust/rev.html) and
/// [forward](https://enzyme.mit.edu/rust/fwd.html) mode is available online.
#[derive(Clone, Copy, Eq, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]

15
compiler/rustc_codegen_llvm/src/back/write.rs
View file

@ -564,19 +564,16 @@ pub(crate) unsafe fn llvm_optimize(
// FIXME(ZuseZ4): In a future update we could figure out how to only optimize individual functions getting
// differentiated.
let consider_ad = cfg!(llvm_enzyme) && config.autodiff.contains(&config::AutoDiff::Enable);
let run_enzyme = autodiff_stage == AutodiffStage::DuringAD;
let unroll_loops;
let vectorize_slp;
let vectorize_loop;
let run_enzyme = cfg!(llvm_enzyme) && autodiff_stage == AutodiffStage::DuringAD;
// When we build rustc with enzyme/autodiff support, we want to postpone size-increasing
// optimizations until after differentiation. Our pipeline is thus: (opt + enzyme), (full opt).
// We therefore have two calls to llvm_optimize, if autodiff is used.
//
// FIXME(ZuseZ4): Before shipping on nightly,
// we should make this more granular, or at least check that the user has at least one autodiff
// call in their code, to justify altering the compilation pipeline.
if cfg!(llvm_enzyme) && autodiff_stage != AutodiffStage::PostAD {
if consider_ad && autodiff_stage != AutodiffStage::PostAD {
unroll_loops = false;
vectorize_slp = false;
vectorize_loop = false;
@ -706,10 +703,8 @@ pub(crate) unsafe fn optimize(
// If we know that we will later run AD, then we disable vectorization and loop unrolling.
// Otherwise we pretend AD is already done and run the normal opt pipeline (=PostAD).
// FIXME(ZuseZ4): Make this more granular, only set PreAD if we actually have autodiff
// usages, not just if we build rustc with autodiff support.
let autodiff_stage =
if cfg!(llvm_enzyme) { AutodiffStage::PreAD } else { AutodiffStage::PostAD };
let consider_ad = cfg!(llvm_enzyme) && config.autodiff.contains(&config::AutoDiff::Enable);
let autodiff_stage = if consider_ad { AutodiffStage::PreAD } else { AutodiffStage::PostAD };
return unsafe {
llvm_optimize(cgcx, dcx, module, config, opt_level, opt_stage, autodiff_stage)
};

2
compiler/rustc_monomorphize/src/partitioning/autodiff.rs
View file

@ -66,7 +66,7 @@ pub(crate) fn find_autodiff_source_functions<'tcx>(
let mut autodiff_items: Vec<AutoDiffItem> = vec![];
for (item, instance) in autodiff_mono_items {
let target_id = instance.def_id();
let cg_fn_attr = tcx.codegen_fn_attrs(target_id).autodiff_item.clone();
let cg_fn_attr = &tcx.codegen_fn_attrs(target_id).autodiff_item;
let Some(target_attrs) = cg_fn_attr else {
continue;
};