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Rollup merge of #82736 - spastorino:mir-opt-level-perf-changes, r=oli-obk

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Bump optimization from mir_opt_level 2 to 3 and 3 to 4 and make "release" be level 2 by default

r? `@oli-obk`
This commit is contained in:
Guillaume Gomez 2021-03-05 21:44:40 +01:00 • committed by GitHub
commit 15c148b4f2
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GPG key ID: 4AEE18F83AFDEB23
85 changed files with 117 additions and 109 deletions
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2
compiler/rustc_interface/src/tests.rs
View file

@ -566,7 +566,7 @@ fn test_debugging_options_tracking_hash() {
tracked!(link_only, true);
tracked!(merge_functions, Some(MergeFunctions::Disabled));
tracked!(mir_emit_retag, true);
tracked!(mir_opt_level, 3);
tracked!(mir_opt_level, Some(4));
tracked!(mutable_noalias, true);
tracked!(new_llvm_pass_manager, true);
tracked!(no_codegen, true);

2
compiler/rustc_mir/src/transform/const_goto.rs
View file

@ -28,7 +28,7 @@ pub struct ConstGoto;
impl<'tcx> MirPass<'tcx> for ConstGoto {
fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
if tcx.sess.opts.debugging_opts.mir_opt_level < 3 {
if tcx.sess.mir_opt_level() < 4 {
return;
}
trace!("Running ConstGoto on {:?}", body.source);

12
compiler/rustc_mir/src/transform/const_prop.rs
View file

@ -725,7 +725,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
return None;
}
if self.tcx.sess.opts.debugging_opts.mir_opt_level >= 3 {
if self.tcx.sess.mir_opt_level() >= 4 {
self.eval_rvalue_with_identities(rvalue, place)
} else {
self.use_ecx(|this| this.ecx.eval_rvalue_into_place(rvalue, place))
@ -903,7 +903,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
/// Returns `true` if and only if this `op` should be const-propagated into.
fn should_const_prop(&mut self, op: &OpTy<'tcx>) -> bool {
let mir_opt_level = self.tcx.sess.opts.debugging_opts.mir_opt_level;
let mir_opt_level = self.tcx.sess.mir_opt_level();
if mir_opt_level == 0 {
return false;
@ -1071,9 +1071,9 @@ impl<'mir, 'tcx> MutVisitor<'tcx> for ConstPropagator<'mir, 'tcx> {
fn visit_operand(&mut self, operand: &mut Operand<'tcx>, location: Location) {
self.super_operand(operand, location);
// Only const prop copies and moves on `mir_opt_level=2` as doing so
// Only const prop copies and moves on `mir_opt_level=3` as doing so
// currently slightly increases compile time in some cases.
if self.tcx.sess.opts.debugging_opts.mir_opt_level >= 2 {
if self.tcx.sess.mir_opt_level() >= 3 {
self.propagate_operand(operand)
}
}
@ -1253,7 +1253,7 @@ impl<'mir, 'tcx> MutVisitor<'tcx> for ConstPropagator<'mir, 'tcx> {
TerminatorKind::SwitchInt { ref mut discr, .. } => {
// FIXME: This is currently redundant with `visit_operand`, but sadly
// always visiting operands currently causes a perf regression in LLVM codegen, so
// `visit_operand` currently only runs for propagates places for `mir_opt_level=3`.
// `visit_operand` currently only runs for propagates places for `mir_opt_level=4`.
self.propagate_operand(discr)
}
// None of these have Operands to const-propagate.
@ -1272,7 +1272,7 @@ impl<'mir, 'tcx> MutVisitor<'tcx> for ConstPropagator<'mir, 'tcx> {
// Every argument in our function calls have already been propagated in `visit_operand`.
//
// NOTE: because LLVM codegen gives slight performance regressions with it, so this is
// gated on `mir_opt_level=2`.
// gated on `mir_opt_level=3`.
TerminatorKind::Call { .. } => {}
}

2
compiler/rustc_mir/src/transform/deduplicate_blocks.rs
View file

@ -16,7 +16,7 @@ pub struct DeduplicateBlocks;
impl<'tcx> MirPass<'tcx> for DeduplicateBlocks {
fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
if tcx.sess.opts.debugging_opts.mir_opt_level < 3 {
if tcx.sess.mir_opt_level() < 4 {
return;
}
debug!("Running DeduplicateBlocks on `{:?}`", body.source);

4
compiler/rustc_mir/src/transform/dest_prop.rs
View file

@ -127,9 +127,9 @@ pub struct DestinationPropagation;
impl<'tcx> MirPass<'tcx> for DestinationPropagation {
fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
// Only run at mir-opt-level=2 or higher for now (we don't fix up debuginfo and remove
// Only run at mir-opt-level=3 or higher for now (we don't fix up debuginfo and remove
// storage statements at the moment).
if tcx.sess.opts.debugging_opts.mir_opt_level <= 1 {
if tcx.sess.mir_opt_level() < 3 {
return;
}

2
compiler/rustc_mir/src/transform/early_otherwise_branch.rs
View file

@ -26,7 +26,7 @@ pub struct EarlyOtherwiseBranch;
impl<'tcx> MirPass<'tcx> for EarlyOtherwiseBranch {
fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
if tcx.sess.opts.debugging_opts.mir_opt_level < 2 {
if tcx.sess.mir_opt_level() < 3 {
return;
}
trace!("running EarlyOtherwiseBranch on {:?}", body.source);

2
compiler/rustc_mir/src/transform/inline.rs
View file

@ -52,7 +52,7 @@ crate fn is_enabled(tcx: TyCtxt<'_>) -> bool {
return enabled;
}
tcx.sess.opts.debugging_opts.mir_opt_level >= 2
tcx.sess.mir_opt_level() >= 3
}
impl<'tcx> MirPass<'tcx> for Inline {

2
compiler/rustc_mir/src/transform/match_branches.rs
View file

@ -40,7 +40,7 @@ pub struct MatchBranchSimplification;
impl<'tcx> MirPass<'tcx> for MatchBranchSimplification {
fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
if tcx.sess.opts.debugging_opts.mir_opt_level <= 1 {
if tcx.sess.mir_opt_level() < 3 {
return;
}

2
compiler/rustc_mir/src/transform/mod.rs
View file

@ -475,7 +475,7 @@ fn run_post_borrowck_cleanup_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tc
}
fn run_optimization_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
let mir_opt_level = tcx.sess.opts.debugging_opts.mir_opt_level;
let mir_opt_level = tcx.sess.mir_opt_level();
// Lowering generator control-flow and variables has to happen before we do anything else
// to them. We run some optimizations before that, because they may be harder to do on the state

2
compiler/rustc_mir/src/transform/multiple_return_terminators.rs
View file

@ -10,7 +10,7 @@ pub struct MultipleReturnTerminators;
impl<'tcx> MirPass<'tcx> for MultipleReturnTerminators {
fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
if tcx.sess.opts.debugging_opts.mir_opt_level < 3 {
if tcx.sess.mir_opt_level() < 4 {
return;
}

2
compiler/rustc_mir/src/transform/nrvo.rs
View file

@ -34,7 +34,7 @@ pub struct RenameReturnPlace;
impl<'tcx> MirPass<'tcx> for RenameReturnPlace {
fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut mir::Body<'tcx>) {
if tcx.sess.opts.debugging_opts.mir_opt_level == 0 {
if tcx.sess.mir_opt_level() == 0 {
return;
}

4
compiler/rustc_mir/src/transform/unreachable_prop.rs
View file

@ -12,8 +12,8 @@ pub struct UnreachablePropagation;
impl MirPass<'_> for UnreachablePropagation {
fn run_pass<'tcx>(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
if tcx.sess.opts.debugging_opts.mir_opt_level < 3 {
// Enable only under -Zmir-opt-level=3 as in some cases (check the deeply-nested-opt
if tcx.sess.mir_opt_level() < 4 {
// Enable only under -Zmir-opt-level=4 as in some cases (check the deeply-nested-opt
// perf benchmark) LLVM may spend quite a lot of time optimizing the generated code.
return;
}

30
compiler/rustc_session/src/config.rs
View file

@ -1938,21 +1938,23 @@ pub fn build_session_options(matches: &getopts::Matches) -> Options {
Some(SymbolManglingVersion::V0) => {}
}
if debugging_opts.mir_opt_level > 1 {
// Functions inlined during MIR transform can, at best, make it impossible to
// effectively cover inlined functions, and, at worst, break coverage map generation
// during LLVM codegen. For example, function counter IDs are only unique within a
// function. Inlining after these counters are injected can produce duplicate counters,
// resulting in an invalid coverage map (and ICE); so this option combination is not
// allowed.
early_warn(
error_format,
&format!(
"`-Z mir-opt-level={}` (or any level > 1) enables function inlining, which \
if let Some(mir_opt_level) = debugging_opts.mir_opt_level {
if mir_opt_level > 1 {
// Functions inlined during MIR transform can, at best, make it impossible to
// effectively cover inlined functions, and, at worst, break coverage map generation
// during LLVM codegen. For example, function counter IDs are only unique within a
// function. Inlining after these counters are injected can produce duplicate counters,
// resulting in an invalid coverage map (and ICE); so this option combination is not
// allowed.
early_warn(
error_format,
&format!(
"`-Z mir-opt-level={}` (or any level > 1) enables function inlining, which \
is incompatible with `-Z instrument-coverage`. Inlining will be disabled.",
debugging_opts.mir_opt_level,
),
);
mir_opt_level,
),
);
}
}
}

4
compiler/rustc_session/src/options.rs
View file

@ -999,8 +999,8 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
mir_emit_retag: bool = (false, parse_bool, [TRACKED],
"emit Retagging MIR statements, interpreted e.g., by miri; implies -Zmir-opt-level=0 \
(default: no)"),
mir_opt_level: usize = (1, parse_uint, [TRACKED],
"MIR optimization level (0-3; default: 1)"),
mir_opt_level: Option<usize> = (None, parse_opt_uint, [TRACKED],
"MIR optimization level (0-4; default: 1 in non optimized builds and 2 in optimized builds)"),
mutable_noalias: bool = (false, parse_bool, [TRACKED],
"emit noalias metadata for mutable references (default: no)"),
new_llvm_pass_manager: bool = (false, parse_bool, [TRACKED],

6
compiler/rustc_session/src/session.rs
View file

@ -640,6 +640,12 @@ impl Session {
pub fn binary_dep_depinfo(&self) -> bool {
self.opts.debugging_opts.binary_dep_depinfo
}
pub fn mir_opt_level(&self) -> usize {
self.opts
.debugging_opts
.mir_opt_level
.unwrap_or_else(|| if self.opts.optimize != config::OptLevel::No { 2 } else { 1 })
}
/// Gets the features enabled for the current compilation session.
/// DO NOT USE THIS METHOD if there is a TyCtxt available, as it circumvents