Auto merge of #112040 - cjgillot:separate-const-switch, r=oli-obk
Enable ConstGoto and SeparateConstSwitch passes by default These 2 passes implement a limited form of jump-threading. Filing this PR to see if enabling them would be lighter than https://github.com/rust-lang/rust/pull/107009.
This commit is contained in:
bors
commit
789dd0b2a2
@ -28,7 +28,7 @@ pub struct ConstGoto;
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impl<'tcx> MirPass<'tcx> for ConstGoto {
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fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
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sess.mir_opt_level() >= 4
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sess.mir_opt_level() >= 2
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}
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fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
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@ -103,7 +103,14 @@ impl<'tcx> MirPass<'tcx> for ConstProp {
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// That would require a uniform one-def no-mutation analysis
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// and RPO (or recursing when needing the value of a local).
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let mut optimization_finder = ConstPropagator::new(body, dummy_body, tcx);
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optimization_finder.visit_body(body);
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// Traverse the body in reverse post-order, to ensure that `FullConstProp` locals are
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// assigned before being read.
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let postorder = body.basic_blocks.postorder().to_vec();
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for bb in postorder.into_iter().rev() {
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let data = &mut body.basic_blocks.as_mut_preserves_cfg()[bb];
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optimization_finder.visit_basic_block_data(bb, data);
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}
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trace!("ConstProp done for {:?}", def_id);
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}
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@ -789,12 +796,6 @@ impl<'tcx> MutVisitor<'tcx> for ConstPropagator<'_, 'tcx> {
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self.tcx
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}
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fn visit_body(&mut self, body: &mut Body<'tcx>) {
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for (bb, data) in body.basic_blocks.as_mut_preserves_cfg().iter_enumerated_mut() {
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self.visit_basic_block_data(bb, data);
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}
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}
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fn visit_operand(&mut self, operand: &mut Operand<'tcx>, location: Location) {
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self.super_operand(operand, location);
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@ -885,14 +886,23 @@ impl<'tcx> MutVisitor<'tcx> for ConstPropagator<'_, 'tcx> {
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}
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}
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StatementKind::StorageLive(local) => {
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let frame = self.ecx.frame_mut();
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frame.locals[local].value =
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LocalValue::Live(interpret::Operand::Immediate(interpret::Immediate::Uninit));
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}
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StatementKind::StorageDead(local) => {
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let frame = self.ecx.frame_mut();
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frame.locals[local].value = LocalValue::Dead;
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Self::remove_const(&mut self.ecx, local);
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}
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// We do not need to mark dead locals as such. For `FullConstProp` locals,
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// this allows to propagate the single assigned value in this case:
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// ```
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// let x = SOME_CONST;
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// if a {
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// f(copy x);
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// StorageDead(x);
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// } else {
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// g(copy x);
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// StorageDead(x);
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// }
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// ```
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//
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// This may propagate a constant where the local would be uninit or dead.
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// In both cases, this does not matter, as those reads would be UB anyway.
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_ => {}
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}
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}
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@ -559,10 +559,13 @@ fn run_optimization_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
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// inst combine is after MatchBranchSimplification to clean up Ne(_1, false)
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&multiple_return_terminators::MultipleReturnTerminators,
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&instsimplify::InstSimplify,
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&separate_const_switch::SeparateConstSwitch,
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&simplify::SimplifyLocals::BeforeConstProp,
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©_prop::CopyProp,
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&ref_prop::ReferencePropagation,
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// Perform `SeparateConstSwitch` after SSA-based analyses, as cloning blocks may
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// destroy the SSA property. It should still happen before const-propagation, so the
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// latter pass will leverage the created opportunities.
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&separate_const_switch::SeparateConstSwitch,
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&const_prop::ConstProp,
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&dataflow_const_prop::DataflowConstProp,
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//
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@ -46,7 +46,7 @@ pub struct SeparateConstSwitch;
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impl<'tcx> MirPass<'tcx> for SeparateConstSwitch {
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fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
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sess.mir_opt_level() >= 4
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sess.mir_opt_level() >= 2
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}
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fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
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@ -9,70 +9,61 @@
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let mut _4: std::result::Result<i32, i32>; // in scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:9
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let mut _5: isize; // in scope 0 at $DIR/separate_const_switch.rs:+1:9: +1:10
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let _6: std::result::Result<std::convert::Infallible, i32>; // in scope 0 at $DIR/separate_const_switch.rs:+1:9: +1:10
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let mut _7: !; // in scope 0 at $DIR/separate_const_switch.rs:+1:9: +1:10
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let mut _8: std::result::Result<std::convert::Infallible, i32>; // in scope 0 at $DIR/separate_const_switch.rs:+1:9: +1:10
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let _9: i32; // in scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
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let mut _7: std::result::Result<std::convert::Infallible, i32>; // in scope 0 at $DIR/separate_const_switch.rs:+1:9: +1:10
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let _8: i32; // in scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
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scope 1 {
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debug residual => _6; // in scope 1 at $DIR/separate_const_switch.rs:+1:9: +1:10
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scope 2 {
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scope 8 (inlined #[track_caller] <Result<i32, i32> as FromResidual<Result<Infallible, i32>>>::from_residual) { // at $DIR/separate_const_switch.rs:25:8: 25:10
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debug residual => _8; // in scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
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let _14: i32; // in scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
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let mut _15: i32; // in scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
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debug residual => _6; // in scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
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let _13: i32; // in scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
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let mut _14: i32; // in scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
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scope 9 {
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debug e => _14; // in scope 9 at $SRC_DIR/core/src/result.rs:LL:COL
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debug e => _13; // in scope 9 at $SRC_DIR/core/src/result.rs:LL:COL
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scope 10 (inlined <i32 as From<i32>>::from) { // at $SRC_DIR/core/src/result.rs:LL:COL
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debug t => _14; // in scope 10 at $SRC_DIR/core/src/convert/mod.rs:LL:COL
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debug t => _13; // in scope 10 at $SRC_DIR/core/src/convert/mod.rs:LL:COL
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}
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}
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}
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}
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}
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scope 3 {
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debug val => _9; // in scope 3 at $DIR/separate_const_switch.rs:+1:8: +1:10
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debug val => _8; // in scope 3 at $DIR/separate_const_switch.rs:+1:8: +1:10
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scope 4 {
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}
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}
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scope 5 (inlined <Result<i32, i32> as Try>::branch) { // at $DIR/separate_const_switch.rs:25:8: 25:10
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debug self => _4; // in scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
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let mut _10: isize; // in scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
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debug self => _1; // in scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
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let mut _9: isize; // in scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
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let _10: i32; // in scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
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let _11: i32; // in scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
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let _12: i32; // in scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
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let mut _13: std::result::Result<std::convert::Infallible, i32>; // in scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
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let mut _12: std::result::Result<std::convert::Infallible, i32>; // in scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
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scope 6 {
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debug v => _11; // in scope 6 at $SRC_DIR/core/src/result.rs:LL:COL
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debug v => _10; // in scope 6 at $SRC_DIR/core/src/result.rs:LL:COL
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}
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scope 7 {
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debug e => _12; // in scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
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debug e => _11; // in scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
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}
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}
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bb0: {
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StorageLive(_2); // scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
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StorageLive(_3); // scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
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StorageLive(_4); // scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:9
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_4 = _1; // scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:9
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StorageLive(_10); // scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
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StorageLive(_11); // scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
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StorageLive(_12); // scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
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_10 = discriminant(_4); // scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
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switchInt(move _10) -> [0: bb7, 1: bb5, otherwise: bb6]; // scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
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_9 = discriminant(_1); // scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
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switchInt(move _9) -> [0: bb7, 1: bb5, otherwise: bb6]; // scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
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}
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bb1: {
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StorageDead(_12); // scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
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StorageDead(_11); // scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
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StorageDead(_4); // scope 0 at $DIR/separate_const_switch.rs:+1:9: +1:10
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StorageDead(_10); // scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
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_5 = discriminant(_3); // scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
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switchInt(move _5) -> [0: bb2, 1: bb4, otherwise: bb3]; // scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
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}
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bb2: {
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StorageLive(_9); // scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
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_9 = ((_3 as Continue).0: i32); // scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
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_2 = _9; // scope 4 at $DIR/separate_const_switch.rs:+1:8: +1:10
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StorageDead(_9); // scope 0 at $DIR/separate_const_switch.rs:+1:9: +1:10
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_0 = Result::<i32, i32>::Ok(move _2); // scope 0 at $DIR/separate_const_switch.rs:+1:5: +1:11
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StorageDead(_2); // scope 0 at $DIR/separate_const_switch.rs:+1:10: +1:11
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_8 = ((_3 as Continue).0: i32); // scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
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_0 = Result::<i32, i32>::Ok(_8); // scope 0 at $DIR/separate_const_switch.rs:+1:5: +1:11
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StorageDead(_3); // scope 0 at $DIR/separate_const_switch.rs:+2:1: +2:2
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return; // scope 0 at $DIR/separate_const_switch.rs:+2:2: +2:2
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}
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@ -82,30 +73,19 @@
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}
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bb4: {
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StorageLive(_6); // scope 0 at $DIR/separate_const_switch.rs:+1:9: +1:10
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_6 = ((_3 as Break).0: std::result::Result<std::convert::Infallible, i32>); // scope 0 at $DIR/separate_const_switch.rs:+1:9: +1:10
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StorageLive(_8); // scope 2 at $DIR/separate_const_switch.rs:+1:9: +1:10
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_8 = _6; // scope 2 at $DIR/separate_const_switch.rs:+1:9: +1:10
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StorageLive(_14); // scope 2 at $DIR/separate_const_switch.rs:+1:8: +1:10
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_14 = move ((_8 as Err).0: i32); // scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
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StorageLive(_15); // scope 9 at $SRC_DIR/core/src/result.rs:LL:COL
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_15 = move _14; // scope 10 at $SRC_DIR/core/src/convert/mod.rs:LL:COL
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_0 = Result::<i32, i32>::Err(move _15); // scope 9 at $SRC_DIR/core/src/result.rs:LL:COL
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StorageDead(_15); // scope 9 at $SRC_DIR/core/src/result.rs:LL:COL
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StorageDead(_14); // scope 2 at $DIR/separate_const_switch.rs:+1:8: +1:10
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StorageDead(_8); // scope 2 at $DIR/separate_const_switch.rs:+1:9: +1:10
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StorageDead(_6); // scope 0 at $DIR/separate_const_switch.rs:+1:9: +1:10
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StorageDead(_2); // scope 0 at $DIR/separate_const_switch.rs:+1:10: +1:11
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_13 = ((_6 as Err).0: i32); // scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
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_0 = Result::<i32, i32>::Err(move _13); // scope 9 at $SRC_DIR/core/src/result.rs:LL:COL
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StorageDead(_3); // scope 0 at $DIR/separate_const_switch.rs:+2:1: +2:2
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return; // scope 0 at $DIR/separate_const_switch.rs:+2:2: +2:2
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}
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bb5: {
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_12 = move ((_4 as Err).0: i32); // scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
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StorageLive(_13); // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
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_13 = Result::<Infallible, i32>::Err(move _12); // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
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_3 = ControlFlow::<Result<Infallible, i32>, i32>::Break(move _13); // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
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StorageDead(_13); // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
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_11 = ((_1 as Err).0: i32); // scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
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StorageLive(_12); // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
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_12 = Result::<Infallible, i32>::Err(move _11); // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
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_3 = ControlFlow::<Result<Infallible, i32>, i32>::Break(move _12); // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
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StorageDead(_12); // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
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goto -> bb1; // scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
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}
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@ -114,8 +94,8 @@
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}
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bb7: {
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_11 = move ((_4 as Ok).0: i32); // scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
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_3 = ControlFlow::<Result<Infallible, i32>, i32>::Continue(move _11); // scope 6 at $SRC_DIR/core/src/result.rs:LL:COL
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_10 = ((_1 as Ok).0: i32); // scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
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_3 = ControlFlow::<Result<Infallible, i32>, i32>::Continue(move _10); // scope 6 at $SRC_DIR/core/src/result.rs:LL:COL
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goto -> bb1; // scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
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}
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}
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@ -34,13 +34,8 @@
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}
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bb1: {
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StorageLive(_6); // scope 0 at $DIR/separate_const_switch.rs:+8:17: +8:18
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_6 = ((_1 as Err).0: usize); // scope 0 at $DIR/separate_const_switch.rs:+8:17: +8:18
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StorageLive(_7); // scope 2 at $DIR/separate_const_switch.rs:+8:42: +8:43
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_7 = _6; // scope 2 at $DIR/separate_const_switch.rs:+8:42: +8:43
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_2 = ControlFlow::<usize, i32>::Break(move _7); // scope 2 at $DIR/separate_const_switch.rs:+8:23: +8:44
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StorageDead(_7); // scope 2 at $DIR/separate_const_switch.rs:+8:43: +8:44
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StorageDead(_6); // scope 0 at $DIR/separate_const_switch.rs:+8:43: +8:44
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_2 = ControlFlow::<usize, i32>::Break(_6); // scope 2 at $DIR/separate_const_switch.rs:+8:23: +8:44
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goto -> bb4; // scope 0 at $DIR/separate_const_switch.rs:+8:43: +8:44
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}
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@ -49,13 +44,8 @@
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}
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bb3: {
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StorageLive(_4); // scope 0 at $DIR/separate_const_switch.rs:+7:16: +7:17
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_4 = ((_1 as Ok).0: i32); // scope 0 at $DIR/separate_const_switch.rs:+7:16: +7:17
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StorageLive(_5); // scope 1 at $DIR/separate_const_switch.rs:+7:44: +7:45
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_5 = _4; // scope 1 at $DIR/separate_const_switch.rs:+7:44: +7:45
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_2 = ControlFlow::<usize, i32>::Continue(move _5); // scope 1 at $DIR/separate_const_switch.rs:+7:22: +7:46
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StorageDead(_5); // scope 1 at $DIR/separate_const_switch.rs:+7:45: +7:46
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StorageDead(_4); // scope 0 at $DIR/separate_const_switch.rs:+7:45: +7:46
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_2 = ControlFlow::<usize, i32>::Continue(_4); // scope 1 at $DIR/separate_const_switch.rs:+7:22: +7:46
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goto -> bb4; // scope 0 at $DIR/separate_const_switch.rs:+7:45: +7:46
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}
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@ -73,13 +63,8 @@
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}
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bb6: {
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StorageLive(_9); // scope 0 at $DIR/separate_const_switch.rs:+11:31: +11:32
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_9 = ((_2 as Continue).0: i32); // scope 0 at $DIR/separate_const_switch.rs:+11:31: +11:32
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StorageLive(_10); // scope 3 at $DIR/separate_const_switch.rs:+11:42: +11:43
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_10 = _9; // scope 3 at $DIR/separate_const_switch.rs:+11:42: +11:43
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_0 = Option::<i32>::Some(move _10); // scope 3 at $DIR/separate_const_switch.rs:+11:37: +11:44
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StorageDead(_10); // scope 3 at $DIR/separate_const_switch.rs:+11:43: +11:44
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StorageDead(_9); // scope 0 at $DIR/separate_const_switch.rs:+11:43: +11:44
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_0 = Option::<i32>::Some(_9); // scope 3 at $DIR/separate_const_switch.rs:+11:37: +11:44
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goto -> bb7; // scope 0 at $DIR/separate_const_switch.rs:+11:43: +11:44
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}
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