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Auto merge of #78360 - tmiasko:storage-markers, r=wesleywiser,oli-obk
Remove storage markers if they won't be used during code generation The storage markers constitute a substantial portion of all MIR statements. At the same time, for builds without any optimizations, the storage markers have no further use during and after MIR optimization phase. If storage markers are not necessary for code generation, remove them.
2 parents d2731d8 + 57de468 commit 09db057

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7 files changed

+155
-3
lines changed

7 files changed

+155
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lines changed

‎compiler/rustc_mir/src/transform/mod.rs‎

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@@ -42,6 +42,7 @@ pub mod no_landing_pads;
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pub mod nrvo;
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pub mod promote_consts;
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pub mod remove_noop_landing_pads;
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pub mod remove_storage_markers;
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pub mod remove_unneeded_drops;
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pub mod required_consts;
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pub mod rustc_peek;
@@ -493,6 +494,7 @@ fn run_optimization_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
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// The main optimizations that we do on MIR.
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let optimizations: &[&dyn MirPass<'tcx>] = &[
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&remove_storage_markers::RemoveStorageMarkers,
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&const_goto::ConstGoto,
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&remove_unneeded_drops::RemoveUnneededDrops,
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&match_branches::MatchBranchSimplification,

‎compiler/rustc_mir/src/transform/remove_storage_markers.rs‎

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//! This pass removes storage markers if they won't be emitted during codegen.
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use crate::transform::MirPass;
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use rustc_middle::mir::*;
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use rustc_middle::ty::TyCtxt;
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pub struct RemoveStorageMarkers;
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impl<'tcx> MirPass<'tcx> for RemoveStorageMarkers {
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fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
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if tcx.sess.emit_lifetime_markers() {
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return;
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}
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trace!("Running RemoveStorageMarkers on {:?}", body.source);
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for data in body.basic_blocks_mut() {
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data.statements.retain(|statement| match statement.kind {
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StatementKind::StorageLive(..)
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| StatementKind::StorageDead(..)
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| StatementKind::Nop => false,
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_ => true,
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})
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}
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}
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}

‎src/test/codegen/try_identity.rs‎

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Original file line numberDiff line numberDiff line change
@@ -1,4 +1,4 @@
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// compile-flags: -C no-prepopulate-passes -Z mir-opt-level=2 -Zunsound-mir-opts
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// compile-flags: -C no-prepopulate-passes -O -Z mir-opt-level=2 -Zunsound-mir-opts
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// Ensure that `x?` has no overhead on `Result<T, E>` due to identity `match`es in lowering.
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// This requires inlining to trigger the MIR optimizations in `SimplifyArmIdentity`.

‎src/test/mir-opt/remove_storage_markers.main.RemoveStorageMarkers.diff‎

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- // MIR for `main` before RemoveStorageMarkers
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+ // MIR for `main` after RemoveStorageMarkers
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fn main() -> () {
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let mut _0: (); // return place in scope 0 at $DIR/remove_storage_markers.rs:6:11: 6:11
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let mut _1: i32; // in scope 0 at $DIR/remove_storage_markers.rs:7:9: 7:16
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let mut _2: std::ops::Range<i32>; // in scope 0 at $DIR/remove_storage_markers.rs:8:14: 8:19
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let mut _3: std::ops::Range<i32>; // in scope 0 at $DIR/remove_storage_markers.rs:8:14: 8:19
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let mut _5: (); // in scope 0 at $DIR/remove_storage_markers.rs:6:1: 11:2
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let _7: (); // in scope 0 at $DIR/remove_storage_markers.rs:8:14: 8:19
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let mut _8: std::option::Option<i32>; // in scope 0 at $DIR/remove_storage_markers.rs:8:14: 8:19
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let mut _9: &mut std::ops::Range<i32>; // in scope 0 at $DIR/remove_storage_markers.rs:8:14: 8:19
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let mut _10: &mut std::ops::Range<i32>; // in scope 0 at $DIR/remove_storage_markers.rs:8:14: 8:19
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let mut _11: isize; // in scope 0 at $DIR/remove_storage_markers.rs:8:9: 8:10
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let mut _13: i32; // in scope 0 at $DIR/remove_storage_markers.rs:8:9: 8:10
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let mut _14: !; // in scope 0 at $DIR/remove_storage_markers.rs:8:5: 10:6
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let _16: (); // in scope 0 at $DIR/remove_storage_markers.rs:8:20: 10:6
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let mut _17: i32; // in scope 0 at $DIR/remove_storage_markers.rs:9:16: 9:17
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scope 1 {
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debug sum => _1; // in scope 1 at $DIR/remove_storage_markers.rs:7:9: 7:16
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let mut _4: std::ops::Range<i32>; // in scope 1 at $DIR/remove_storage_markers.rs:8:14: 8:19
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scope 2 {
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debug iter => _4; // in scope 2 at $DIR/remove_storage_markers.rs:8:14: 8:19
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let mut _6: i32; // in scope 2 at $DIR/remove_storage_markers.rs:8:14: 8:19
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scope 3 {
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debug __next => _6; // in scope 3 at $DIR/remove_storage_markers.rs:8:14: 8:19
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let _12: i32; // in scope 3 at $DIR/remove_storage_markers.rs:8:9: 8:10
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let _15: i32; // in scope 3 at $DIR/remove_storage_markers.rs:8:9: 8:10
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scope 4 {
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debug val => _12; // in scope 4 at $DIR/remove_storage_markers.rs:8:9: 8:10
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}
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scope 5 {
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debug i => _15; // in scope 5 at $DIR/remove_storage_markers.rs:8:9: 8:10
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}
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}
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}
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scope 6 (inlined <std::ops::Range<i32> as IntoIterator>::into_iter) { // at $DIR/remove_storage_markers.rs:8:14: 8:19
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debug self => _3; // in scope 6 at $DIR/remove_storage_markers.rs:8:14: 8:19
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}
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}
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bb0: {
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- StorageLive(_1); // scope 0 at $DIR/remove_storage_markers.rs:7:9: 7:16
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_1 = const 0_i32; // scope 0 at $DIR/remove_storage_markers.rs:7:19: 7:20
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- StorageLive(_2); // scope 1 at $DIR/remove_storage_markers.rs:8:14: 8:19
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- StorageLive(_3); // scope 1 at $DIR/remove_storage_markers.rs:8:14: 8:19
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(_3.0: i32) = const 0_i32; // scope 1 at $DIR/remove_storage_markers.rs:8:14: 8:19
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(_3.1: i32) = const 10_i32; // scope 1 at $DIR/remove_storage_markers.rs:8:14: 8:19
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_2 = move _3; // scope 6 at $DIR/remove_storage_markers.rs:8:14: 8:19
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- StorageDead(_3); // scope 1 at $DIR/remove_storage_markers.rs:8:18: 8:19
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- StorageLive(_4); // scope 1 at $DIR/remove_storage_markers.rs:8:14: 8:19
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_4 = move _2; // scope 1 at $DIR/remove_storage_markers.rs:8:14: 8:19
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goto -> bb1; // scope 2 at $DIR/remove_storage_markers.rs:8:5: 10:6
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}
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bb1: {
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- StorageLive(_6); // scope 2 at $DIR/remove_storage_markers.rs:8:14: 8:19
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- StorageLive(_7); // scope 3 at $DIR/remove_storage_markers.rs:8:14: 8:19
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- StorageLive(_8); // scope 3 at $DIR/remove_storage_markers.rs:8:14: 8:19
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- StorageLive(_9); // scope 3 at $DIR/remove_storage_markers.rs:8:14: 8:19
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- StorageLive(_10); // scope 3 at $DIR/remove_storage_markers.rs:8:14: 8:19
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_10 = &mut _4; // scope 3 at $DIR/remove_storage_markers.rs:8:14: 8:19
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_9 = &mut (*_10); // scope 3 at $DIR/remove_storage_markers.rs:8:14: 8:19
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_8 = <std::ops::Range<i32> as Iterator>::next(move _9) -> bb2; // scope 3 at $DIR/remove_storage_markers.rs:8:14: 8:19
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// mir::Constant
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// + span: $DIR/remove_storage_markers.rs:8:14: 8:19
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// + literal: Const { ty: for<'r> fn(&'r mut std::ops::Range<i32>) -> std::option::Option<<std::ops::Range<i32> as std::iter::Iterator>::Item> {<std::ops::Range<i32> as std::iter::Iterator>::next}, val: Value(Scalar(<ZST>)) }
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}
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bb2: {
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- StorageDead(_9); // scope 3 at $DIR/remove_storage_markers.rs:8:18: 8:19
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_11 = discriminant(_8); // scope 3 at $DIR/remove_storage_markers.rs:8:9: 8:10
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switchInt(move _11) -> [0_isize: bb3, otherwise: bb4]; // scope 3 at $DIR/remove_storage_markers.rs:8:9: 8:10
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}
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bb3: {
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_0 = const (); // scope 3 at $DIR/remove_storage_markers.rs:8:5: 10:6
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- StorageDead(_10); // scope 3 at $DIR/remove_storage_markers.rs:8:18: 8:19
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- StorageDead(_8); // scope 3 at $DIR/remove_storage_markers.rs:8:18: 8:19
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- StorageDead(_7); // scope 3 at $DIR/remove_storage_markers.rs:8:18: 8:19
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- StorageDead(_6); // scope 2 at $DIR/remove_storage_markers.rs:10:5: 10:6
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- StorageDead(_4); // scope 1 at $DIR/remove_storage_markers.rs:10:5: 10:6
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- StorageDead(_2); // scope 1 at $DIR/remove_storage_markers.rs:8:18: 8:19
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- StorageDead(_1); // scope 0 at $DIR/remove_storage_markers.rs:11:1: 11:2
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return; // scope 0 at $DIR/remove_storage_markers.rs:11:2: 11:2
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}
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bb4: {
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- StorageLive(_12); // scope 3 at $DIR/remove_storage_markers.rs:8:9: 8:10
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_12 = ((_8 as Some).0: i32); // scope 3 at $DIR/remove_storage_markers.rs:8:9: 8:10
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- StorageLive(_13); // scope 4 at $DIR/remove_storage_markers.rs:8:9: 8:10
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_13 = _12; // scope 4 at $DIR/remove_storage_markers.rs:8:9: 8:10
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_6 = move _13; // scope 4 at $DIR/remove_storage_markers.rs:8:9: 8:10
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_7 = const (); // scope 4 at $DIR/remove_storage_markers.rs:8:9: 8:10
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- StorageDead(_13); // scope 4 at $DIR/remove_storage_markers.rs:8:9: 8:10
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- StorageDead(_12); // scope 3 at $DIR/remove_storage_markers.rs:8:9: 8:10
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- StorageDead(_10); // scope 3 at $DIR/remove_storage_markers.rs:8:18: 8:19
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- StorageDead(_8); // scope 3 at $DIR/remove_storage_markers.rs:8:18: 8:19
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- StorageDead(_7); // scope 3 at $DIR/remove_storage_markers.rs:8:18: 8:19
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- StorageLive(_15); // scope 3 at $DIR/remove_storage_markers.rs:8:9: 8:10
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_15 = _6; // scope 3 at $DIR/remove_storage_markers.rs:8:14: 8:19
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- StorageLive(_16); // scope 5 at $DIR/remove_storage_markers.rs:8:20: 10:6
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- StorageLive(_17); // scope 5 at $DIR/remove_storage_markers.rs:9:16: 9:17
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_17 = _15; // scope 5 at $DIR/remove_storage_markers.rs:9:16: 9:17
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_1 = Add(_1, move _17); // scope 5 at $DIR/remove_storage_markers.rs:9:9: 9:17
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- StorageDead(_17); // scope 5 at $DIR/remove_storage_markers.rs:9:16: 9:17
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_16 = const (); // scope 5 at $DIR/remove_storage_markers.rs:8:20: 10:6
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- StorageDead(_16); // scope 5 at $DIR/remove_storage_markers.rs:10:5: 10:6
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_5 = const (); // scope 2 at $DIR/remove_storage_markers.rs:8:5: 10:6
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- StorageDead(_15); // scope 3 at $DIR/remove_storage_markers.rs:10:5: 10:6
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- StorageDead(_6); // scope 2 at $DIR/remove_storage_markers.rs:10:5: 10:6
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goto -> bb1; // scope 2 at $DIR/remove_storage_markers.rs:8:5: 10:6
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}
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}
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‎src/test/mir-opt/remove_storage_markers.rs‎

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// Checks that storage markers are removed at opt-level=0.
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//
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// compile-flags: -C opt-level=0 -Coverflow-checks=off
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// EMIT_MIR remove_storage_markers.main.RemoveStorageMarkers.diff
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fn main() {
7+
let mut sum = 0;
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for i in 0..10 {
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sum += i;
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}
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}

‎src/test/run-make/const_fn_mir/dump.mir‎

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@@ -5,15 +5,13 @@ fn main() -> () {
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let _1: i32; // in scope 0 at main.rs:9:5: 9:10
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bb0: {
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StorageLive(_1); // scope 0 at main.rs:9:5: 9:10
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_1 = foo() -> bb1; // scope 0 at main.rs:9:5: 9:10
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// mir::Constant
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// + span: main.rs:9:5: 9:8
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// + literal: Const { ty: fn() -> i32 {foo}, val: Value(Scalar(<ZST>)) }
1312
}
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bb1: {
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StorageDead(_1); // scope 0 at main.rs:9:10: 9:11
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_0 = const (); // scope 0 at main.rs:8:11: 10:2
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return; // scope 0 at main.rs:10:2: 10:2
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}

‎src/tools/compiletest/src/runtest.rs‎

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@@ -1957,6 +1957,7 @@ impl<'test> TestCx<'test> {
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}
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MirOpt => {
19591959
rustc.args(&[
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"-Copt-level=1",
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"-Zdump-mir=all",
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"-Zmir-opt-level=3",
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"-Zvalidate-mir",

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