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egraph-based midend: draw the rest of the owl (productionized). (#4953)

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* egraph-based midend: draw the rest of the owl.

* Rename `egg` submodule of cranelift-codegen to `egraph`.

* Apply some feedback from @jsharp during code walkthrough.

* Remove recursion from find_best_node by doing a single pass.

Rather than recursively computing the lowest-cost node for a given
eclass and memoizing the answer at each eclass node, we can do a single
forward pass; because every eclass node refers only to earlier nodes,
this is sufficient. The behavior may slightly differ from the earlier
behavior because we cannot short-circuit costs to zero once a node is
elaborated; but in practice this should not matter.

* Make elaboration non-recursive.

Use an explicit stack instead (with `ElabStackEntry` entries,
alongside a result stack).

* Make elaboration traversal of the domtree non-recursive/stack-safe.

* Work analysis logic in Cranelift-side egraph glue into a general analysis framework in cranelift-egraph.

* Apply static recursion limit to rule application.

* Fix aarch64 wrt dynamic-vector support -- broken rebase.

* Topo-sort cranelift-egraph before cranelift-codegen in publish script, like the comment instructs me to!

* Fix multi-result call testcase.

* Include `cranelift-egraph` in `PUBLISHED_CRATES`.

* Fix atomic_rmw: not really a load.

* Remove now-unnecessary PartialOrd/Ord derivations.

* Address some code-review comments.

* Review feedback.

* Review feedback.

* No overlap in mid-end rules, because we are defining a multi-constructor.

* rustfmt

* Review feedback.

* Review feedback.

* Review feedback.

* Review feedback.

* Remove redundant `mut`.

* Add comment noting what rules can do.

* Review feedback.

* Clarify comment wording.

* Update `has_memory_fence_semantics`.

* Apply @jameysharp's improved loop-level computation.

Co-authored-by: Jamey Sharp <jamey@minilop.net>

* Fix suggestion commit.

* Fix off-by-one in new loop-nest analysis.

* Review feedback.

* Review feedback.

* Review feedback.

* Use `Default`, not `std::default::Default`, as per @fitzgen

Co-authored-by: Nick Fitzgerald <fitzgen@gmail.com>

* Apply @fitzgen's comment elaboration to a doc-comment.

Co-authored-by: Nick Fitzgerald <fitzgen@gmail.com>

* Add stat for hitting the rewrite-depth limit.

* Some code motion in split prelude to make the diff a little clearer wrt `main`.

* Take @jameysharp's suggested `try_into()` usage for blockparam indices.

Co-authored-by: Jamey Sharp <jamey@minilop.net>

* Take @jameysharp's suggestion to avoid double-match on load op.

Co-authored-by: Jamey Sharp <jamey@minilop.net>

* Fix suggestion (add import).

* Review feedback.

* Fix stack_load handling.

* Remove redundant can_store case.

* Take @jameysharp's suggested improvement to FuncEGraph::build() logic

Co-authored-by: Jamey Sharp <jamey@minilop.net>

* Tweaks to FuncEGraph::build() on top of suggestion.

* Take @jameysharp's suggested clarified condition

Co-authored-by: Jamey Sharp <jamey@minilop.net>

* Clean up after suggestion (unused variable).

* Fix loop analysis.

* loop level asserts

* Revert constant-space loop analysis -- edge cases were incorrect, so let's go with the simple thing for now.

* Take @jameysharp's suggestion re: result_tys

Co-authored-by: Jamey Sharp <jamey@minilop.net>

* Fix up after suggestion

* Take @jameysharp's suggestion to use fold rather than reduce

Co-authored-by: Jamey Sharp <jamey@minilop.net>

* Fixup after suggestion

* Take @jameysharp's suggestion to remove elaborate_eclass_use's return value.

* Clarifying comment in terminator insts.

Co-authored-by: Jamey Sharp <jamey@minilop.net>
Co-authored-by: Nick Fitzgerald <fitzgen@gmail.com>
This commit is contained in:
Chris Fallin
2022-10-11 18:15:53 -07:00
committed by GitHub
parent e2f1ced0b6
commit 2be12a5167
59 changed files with 5125 additions and 1580 deletions
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53
cranelift/codegen/src/context.rs
View File

@@ -12,6 +12,7 @@
use crate::alias_analysis::AliasAnalysis;
use crate::dce::do_dce;
use crate::dominator_tree::DominatorTree;
use crate::egraph::FuncEGraph;
use crate::flowgraph::ControlFlowGraph;
use crate::ir::Function;
use crate::isa::TargetIsa;
@@ -104,15 +105,20 @@ impl Context {
/// Compile the function, and emit machine code into a `Vec<u8>`.
///
/// Run the function through all the passes necessary to generate code for the target ISA
/// represented by `isa`, as well as the final step of emitting machine code into a
/// `Vec<u8>`. The machine code is not relocated. Instead, any relocations can be obtained
/// from `compiled_code()`.
/// Run the function through all the passes necessary to generate
/// code for the target ISA represented by `isa`, as well as the
/// final step of emitting machine code into a `Vec<u8>`. The
/// machine code is not relocated. Instead, any relocations can be
/// obtained from `compiled_code()`.
///
/// Performs any optimizations that are enabled, unless
/// `optimize()` was already invoked.
///
/// This function calls `compile`, taking care to resize `mem` as
/// needed, so it provides a safe interface.
/// needed.
///
/// Returns information about the function's code and read-only data.
/// Returns information about the function's code and read-only
/// data.
pub fn compile_and_emit(
&mut self,
isa: &dyn TargetIsa,
@@ -131,15 +137,26 @@ impl Context {
self.verify_if(isa)?;
self.optimize(isa)?;
isa.compile_function(&self.func, self.want_disasm)
}
/// Optimize the function, performing all compilation steps up to
/// but not including machine-code lowering and register
/// allocation.
///
/// Public only for testing purposes.
pub fn optimize(&mut self, isa: &dyn TargetIsa) -> CodegenResult<()> {
let opt_level = isa.flags().opt_level();
log::trace!(
"Compiling (opt level {:?}):\n{}",
"Optimizing (opt level {:?}):\n{}",
opt_level,
self.func.display()
);
self.compute_cfg();
if opt_level != OptLevel::None {
if !isa.flags().use_egraphs() && opt_level != OptLevel::None {
self.preopt(isa)?;
}
if isa.flags().enable_nan_canonicalization() {
@@ -147,7 +164,8 @@ impl Context {
}
self.legalize(isa)?;
if opt_level != OptLevel::None {
if !isa.flags().use_egraphs() && opt_level != OptLevel::None {
self.compute_domtree();
self.compute_loop_analysis();
self.licm(isa)?;
@@ -156,18 +174,29 @@ impl Context {
self.compute_domtree();
self.eliminate_unreachable_code(isa)?;
if opt_level != OptLevel::None {
if isa.flags().use_egraphs() || opt_level != OptLevel::None {
self.dce(isa)?;
}
self.remove_constant_phis(isa)?;
if opt_level != OptLevel::None && isa.flags().enable_alias_analysis() {
if isa.flags().use_egraphs() {
log::debug!(
"About to optimize with egraph phase:\n{}",
self.func.display()
);
self.compute_loop_analysis();
let mut eg = FuncEGraph::new(&self.func, &self.domtree, &self.loop_analysis, &self.cfg);
eg.elaborate(&mut self.func);
log::debug!("After egraph optimization:\n{}", self.func.display());
log::info!("egraph stats: {:?}", eg.stats);
} else if opt_level != OptLevel::None && isa.flags().enable_alias_analysis() {
self.replace_redundant_loads()?;
self.simple_gvn(isa)?;
}
isa.compile_function(&self.func, self.want_disasm)
Ok(())
}
/// Compile the function.