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Auto merge of #134051 - saethlin:partial-ssa-analysis, r=<try>
Do partial SsaLocals analysis in unoptimized builds I've been musing about the perf implications of all the queries that `is_freeze` results in. (it's not like this makes GVN lightweight or light on queries overall, because evaluating consts is still quite a lot of queries)
2 parents fc147b4 + a013042 commit ef3fe2f

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‎compiler/rustc_mir_transform/src/add_retag.rs‎

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -49,8 +49,8 @@ fn may_contain_reference<'tcx>(ty: Ty<'tcx>, depth: u32, tcx: TyCtxt<'tcx>) -> b
4949
}
5050

5151
impl<'tcx> crate::MirPass<'tcx> for AddRetag {
52-
fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
53-
sess.opts.unstable_opts.mir_emit_retag
52+
fn is_enabled(&self, tcx: TyCtxt<'tcx>) -> bool {
53+
tcx.sess.opts.unstable_opts.mir_emit_retag
5454
}
5555

5656
fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {

‎compiler/rustc_mir_transform/src/check_alignment.rs‎

Lines changed: 3 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -3,19 +3,18 @@ use rustc_middle::mir::interpret::Scalar;
33
use rustc_middle::mir::visit::PlaceContext;
44
use rustc_middle::mir::*;
55
use rustc_middle::ty::{Ty, TyCtxt};
6-
use rustc_session::Session;
76

87
use crate::check_pointers::{BorrowCheckMode, PointerCheck, check_pointers};
98

109
pub(super) struct CheckAlignment;
1110

1211
impl<'tcx> crate::MirPass<'tcx> for CheckAlignment {
13-
fn is_enabled(&self, sess: &Session) -> bool {
12+
fn is_enabled(&self, tcx: TyCtxt<'tcx>) -> bool {
1413
// FIXME(#112480) MSVC and rustc disagree on minimum stack alignment on x86 Windows
15-
if sess.target.llvm_target == "i686-pc-windows-msvc" {
14+
if tcx.sess.target.llvm_target == "i686-pc-windows-msvc" {
1615
return false;
1716
}
18-
sess.ub_checks()
17+
tcx.sess.ub_checks()
1918
}
2019

2120
fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {

‎compiler/rustc_mir_transform/src/check_null.rs‎

Lines changed: 2 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -2,15 +2,14 @@ use rustc_index::IndexVec;
22
use rustc_middle::mir::visit::{MutatingUseContext, NonMutatingUseContext, PlaceContext};
33
use rustc_middle::mir::*;
44
use rustc_middle::ty::{Ty, TyCtxt};
5-
use rustc_session::Session;
65

76
use crate::check_pointers::{BorrowCheckMode, PointerCheck, check_pointers};
87

98
pub(super) struct CheckNull;
109

1110
impl<'tcx> crate::MirPass<'tcx> for CheckNull {
12-
fn is_enabled(&self, sess: &Session) -> bool {
13-
sess.ub_checks()
11+
fn is_enabled(&self, tcx: TyCtxt<'tcx>) -> bool {
12+
tcx.sess.ub_checks()
1413
}
1514

1615
fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {

‎compiler/rustc_mir_transform/src/copy_prop.rs‎

Lines changed: 26 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -5,7 +5,8 @@ use rustc_middle::mir::*;
55
use rustc_middle::ty::TyCtxt;
66
use tracing::{debug, instrument};
77

8-
use crate::ssa::SsaLocals;
8+
use crate::pass_manager as pm;
9+
use crate::ssa::{SsaAnalysis, SsaLocals};
910

1011
/// Unify locals that copy each other.
1112
///
@@ -17,19 +18,39 @@ use crate::ssa::SsaLocals;
1718
/// where each of the locals is only assigned once.
1819
///
1920
/// We want to replace all those locals by `_a`, either copied or moved.
20-
pub(super) struct CopyProp;
21+
pub(super) enum CopyProp {
22+
Partial,
23+
Full,
24+
}
2125

2226
impl<'tcx> crate::MirPass<'tcx> for CopyProp {
23-
fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
24-
sess.mir_opt_level() >= 1
27+
fn name(&self) -> &'static str {
28+
match self {
29+
CopyProp::Partial => "CopyProp-partial",
30+
CopyProp::Full => "CopyProp",
31+
}
32+
}
33+
34+
fn is_enabled(&self, tcx: TyCtxt<'tcx>) -> bool {
35+
match self {
36+
CopyProp::Partial => {
37+
tcx.sess.mir_opt_level() == 1
38+
&& !pm::should_run_pass(tcx, &CopyProp::Full, pm::Optimizations::Allowed)
39+
}
40+
CopyProp::Full => tcx.sess.mir_opt_level() >= 2,
41+
}
2542
}
2643

2744
#[instrument(level = "trace", skip(self, tcx, body))]
2845
fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
2946
debug!(def_id = ?body.source.def_id());
3047

3148
let typing_env = body.typing_env(tcx);
32-
let ssa = SsaLocals::new(tcx, body, typing_env);
49+
let ssa_analysis = match self {
50+
CopyProp::Partial => SsaAnalysis::Partial,
51+
CopyProp::Full => SsaAnalysis::Full,
52+
};
53+
let ssa = SsaLocals::new(tcx, body, typing_env, ssa_analysis);
3354

3455
let fully_moved = fully_moved_locals(&ssa, body);
3556
debug!(?fully_moved);

‎compiler/rustc_mir_transform/src/coverage/mod.rs‎

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -31,8 +31,8 @@ use crate::coverage::mappings::ExtractedMappings;
3131
pub(super) struct InstrumentCoverage;
3232

3333
impl<'tcx> crate::MirPass<'tcx> for InstrumentCoverage {
34-
fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
35-
sess.instrument_coverage()
34+
fn is_enabled(&self, tcx: TyCtxt<'tcx>) -> bool {
35+
tcx.sess.instrument_coverage()
3636
}
3737

3838
fn run_pass(&self, tcx: TyCtxt<'tcx>, mir_body: &mut mir::Body<'tcx>) {

‎compiler/rustc_mir_transform/src/dataflow_const_prop.rs‎

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -35,8 +35,8 @@ const PLACE_LIMIT: usize = 100;
3535
pub(super) struct DataflowConstProp;
3636

3737
impl<'tcx> crate::MirPass<'tcx> for DataflowConstProp {
38-
fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
39-
sess.mir_opt_level() >= 3
38+
fn is_enabled(&self, tcx: TyCtxt<'tcx>) -> bool {
39+
tcx.sess.mir_opt_level() >= 3
4040
}
4141

4242
#[instrument(skip_all level = "debug")]

‎compiler/rustc_mir_transform/src/dead_store_elimination.rs‎

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -140,8 +140,8 @@ impl<'tcx> crate::MirPass<'tcx> for DeadStoreElimination {
140140
}
141141
}
142142

143-
fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
144-
sess.mir_opt_level() >= 2
143+
fn is_enabled(&self, tcx: TyCtxt<'tcx>) -> bool {
144+
tcx.sess.mir_opt_level() >= 2
145145
}
146146

147147
fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {

‎compiler/rustc_mir_transform/src/dest_prop.rs‎

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -149,7 +149,7 @@ use tracing::{debug, trace};
149149
pub(super) struct DestinationPropagation;
150150

151151
impl<'tcx> crate::MirPass<'tcx> for DestinationPropagation {
152-
fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
152+
fn is_enabled(&self, tcx: TyCtxt<'tcx>) -> bool {
153153
// For now, only run at MIR opt level 3. Two things need to be changed before this can be
154154
// turned on by default:
155155
// 1. Because of the overeager removal of storage statements, this can cause stack space
@@ -158,7 +158,7 @@ impl<'tcx> crate::MirPass<'tcx> for DestinationPropagation {
158158
// 2. Despite being an overall perf improvement, this still causes a 30% regression in
159159
// keccak. We can temporarily fix this by bounding function size, but in the long term
160160
// we should fix this by being smarter about invalidating analysis results.
161-
sess.mir_opt_level() >= 3
161+
tcx.sess.mir_opt_level() >= 3
162162
}
163163

164164
fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {

‎compiler/rustc_mir_transform/src/early_otherwise_branch.rs‎

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -93,8 +93,8 @@ use crate::patch::MirPatch;
9393
pub(super) struct EarlyOtherwiseBranch;
9494

9595
impl<'tcx> crate::MirPass<'tcx> for EarlyOtherwiseBranch {
96-
fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
97-
sess.mir_opt_level() >= 2
96+
fn is_enabled(&self, tcx: TyCtxt<'tcx>) -> bool {
97+
tcx.sess.mir_opt_level() >= 2
9898
}
9999

100100
fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {

‎compiler/rustc_mir_transform/src/gvn.rs‎

Lines changed: 26 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -107,21 +107,42 @@ use rustc_span::def_id::DefId;
107107
use smallvec::SmallVec;
108108
use tracing::{debug, instrument, trace};
109109

110-
use crate::ssa::{AssignedValue, SsaLocals};
110+
use crate::pass_manager as pm;
111+
use crate::ssa::{AssignedValue, SsaAnalysis, SsaLocals};
111112

112-
pub(super) struct GVN;
113+
pub(super) enum GVN {
114+
Partial,
115+
Full,
116+
}
113117

114118
impl<'tcx> crate::MirPass<'tcx> for GVN {
115-
fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
116-
sess.mir_opt_level() >= 2
119+
fn name(&self) -> &'static str {
120+
match self {
121+
GVN::Partial => "GVN-partial",
122+
GVN::Full => "GVN",
123+
}
124+
}
125+
126+
fn is_enabled(&self, tcx: TyCtxt<'tcx>) -> bool {
127+
match self {
128+
GVN::Partial => {
129+
tcx.sess.mir_opt_level() == 1
130+
&& !pm::should_run_pass(tcx, &GVN::Full, pm::Optimizations::Allowed)
131+
}
132+
GVN::Full => tcx.sess.mir_opt_level() >= 2,
133+
}
117134
}
118135

119136
#[instrument(level = "trace", skip(self, tcx, body))]
120137
fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
121138
debug!(def_id = ?body.source.def_id());
122139

123140
let typing_env = body.typing_env(tcx);
124-
let ssa = SsaLocals::new(tcx, body, typing_env);
141+
let ssa_analysis = match self {
142+
GVN::Partial => SsaAnalysis::Partial,
143+
GVN::Full => SsaAnalysis::Full,
144+
};
145+
let ssa = SsaLocals::new(tcx, body, typing_env, ssa_analysis);
125146
// Clone dominators because we need them while mutating the body.
126147
let dominators = body.basic_blocks.dominators().clone();
127148

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