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tmiaskotmiasko
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copy-prop: Add test case for missed optimization due const prop failure
Currently a failure to completely propagate a constant inhibits propagation of any subsequent locals. Add a test case demonstrating the problem before resolving it.
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‎src/test/mir-opt/copy_propagation_arg.maybe.CopyPropagation.diff

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- // MIR for `maybe` before CopyPropagation
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+ // MIR for `maybe` after CopyPropagation
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fn maybe(_1: &[bool], _2: String) -> () {
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debug m => _1; // in scope 0 at $DIR/copy_propagation_arg.rs:34:10: 34:11
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debug s1 => _2; // in scope 0 at $DIR/copy_propagation_arg.rs:34:22: 34:24
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let mut _0: (); // return place in scope 0 at $DIR/copy_propagation_arg.rs:34:34: 34:34
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let mut _3: bool; // in scope 0 at $DIR/copy_propagation_arg.rs:35:8: 35:12
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let _4: usize; // in scope 0 at $DIR/copy_propagation_arg.rs:35:10: 35:11
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let mut _5: usize; // in scope 0 at $DIR/copy_propagation_arg.rs:35:8: 35:12
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let mut _6: bool; // in scope 0 at $DIR/copy_propagation_arg.rs:35:8: 35:12
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let _7: std::string::String; // in scope 0 at $DIR/copy_propagation_arg.rs:36:13: 36:15
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let mut _8: bool; // in scope 0 at $DIR/copy_propagation_arg.rs:37:12: 37:16
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let _9: usize; // in scope 0 at $DIR/copy_propagation_arg.rs:37:14: 37:15
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let mut _10: usize; // in scope 0 at $DIR/copy_propagation_arg.rs:37:12: 37:16
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let mut _11: bool; // in scope 0 at $DIR/copy_propagation_arg.rs:37:12: 37:16
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let mut _13: bool; // in scope 0 at $DIR/copy_propagation_arg.rs:39:16: 39:20
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let _14: usize; // in scope 0 at $DIR/copy_propagation_arg.rs:39:18: 39:19
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let mut _15: usize; // in scope 0 at $DIR/copy_propagation_arg.rs:39:16: 39:20
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let mut _16: bool; // in scope 0 at $DIR/copy_propagation_arg.rs:39:16: 39:20
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let _18: &std::string::String; // in scope 0 at $DIR/copy_propagation_arg.rs:41:17: 41:20
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let mut _19: bool; // in scope 0 at $DIR/copy_propagation_arg.rs:45:1: 45:2
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let mut _20: bool; // in scope 0 at $DIR/copy_propagation_arg.rs:44:5: 44:6
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let mut _21: bool; // in scope 0 at $DIR/copy_propagation_arg.rs:43:9: 43:10
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scope 1 {
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debug s2 => _7; // in scope 1 at $DIR/copy_propagation_arg.rs:36:13: 36:15
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let _12: std::string::String; // in scope 1 at $DIR/copy_propagation_arg.rs:38:17: 38:19
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scope 2 {
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debug s3 => _12; // in scope 2 at $DIR/copy_propagation_arg.rs:38:17: 38:19
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let _17: std::string::String; // in scope 2 at $DIR/copy_propagation_arg.rs:40:21: 40:23
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scope 3 {
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debug s4 => _17; // in scope 3 at $DIR/copy_propagation_arg.rs:40:21: 40:23
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}
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}
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}
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bb0: {
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_21 = const false; // scope 0 at $DIR/copy_propagation_arg.rs:35:8: 35:12
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_19 = const false; // scope 0 at $DIR/copy_propagation_arg.rs:35:8: 35:12
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_20 = const false; // scope 0 at $DIR/copy_propagation_arg.rs:35:8: 35:12
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_19 = const true; // scope 0 at $DIR/copy_propagation_arg.rs:35:8: 35:12
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StorageLive(_3); // scope 0 at $DIR/copy_propagation_arg.rs:35:8: 35:12
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- StorageLive(_4); // scope 0 at $DIR/copy_propagation_arg.rs:35:10: 35:11
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+ nop; // scope 0 at $DIR/copy_propagation_arg.rs:35:10: 35:11
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_4 = const 0_usize; // scope 0 at $DIR/copy_propagation_arg.rs:35:10: 35:11
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_5 = Len((*_1)); // scope 0 at $DIR/copy_propagation_arg.rs:35:8: 35:12
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_6 = Lt(const 0_usize, _5); // scope 0 at $DIR/copy_propagation_arg.rs:35:8: 35:12
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assert(move _6, "index out of bounds: the len is {} but the index is {}", move _5, const 0_usize) -> [success: bb2, unwind: bb17]; // scope 0 at $DIR/copy_propagation_arg.rs:35:8: 35:12
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}
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bb1 (cleanup): {
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resume; // scope 0 at $DIR/copy_propagation_arg.rs:34:1: 45:2
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}
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bb2: {
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_3 = (*_1)[_4]; // scope 0 at $DIR/copy_propagation_arg.rs:35:8: 35:12
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- StorageDead(_4); // scope 0 at $DIR/copy_propagation_arg.rs:35:11: 35:12
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+ nop; // scope 0 at $DIR/copy_propagation_arg.rs:35:11: 35:12
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switchInt(_3) -> [false: bb3, otherwise: bb4]; // scope 0 at $DIR/copy_propagation_arg.rs:35:5: 44:6
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}
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bb3: {
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_0 = const (); // scope 0 at $DIR/copy_propagation_arg.rs:35:5: 44:6
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goto -> bb14; // scope 0 at $DIR/copy_propagation_arg.rs:35:5: 44:6
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}
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bb4: {
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StorageLive(_7); // scope 0 at $DIR/copy_propagation_arg.rs:36:13: 36:15
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_19 = const false; // scope 0 at $DIR/copy_propagation_arg.rs:36:18: 36:20
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_20 = const true; // scope 0 at $DIR/copy_propagation_arg.rs:36:18: 36:20
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_7 = move _2; // scope 0 at $DIR/copy_propagation_arg.rs:36:18: 36:20
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StorageLive(_8); // scope 1 at $DIR/copy_propagation_arg.rs:37:12: 37:16
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StorageLive(_9); // scope 1 at $DIR/copy_propagation_arg.rs:37:14: 37:15
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_9 = const 1_usize; // scope 1 at $DIR/copy_propagation_arg.rs:37:14: 37:15
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_10 = Len((*_1)); // scope 1 at $DIR/copy_propagation_arg.rs:37:12: 37:16
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_11 = Lt(const 1_usize, _10); // scope 1 at $DIR/copy_propagation_arg.rs:37:12: 37:16
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assert(move _11, "index out of bounds: the len is {} but the index is {}", move _10, const 1_usize) -> [success: bb5, unwind: bb19]; // scope 1 at $DIR/copy_propagation_arg.rs:37:12: 37:16
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}
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bb5: {
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_8 = (*_1)[_9]; // scope 1 at $DIR/copy_propagation_arg.rs:37:12: 37:16
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StorageDead(_9); // scope 1 at $DIR/copy_propagation_arg.rs:37:15: 37:16
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switchInt(_8) -> [false: bb6, otherwise: bb7]; // scope 1 at $DIR/copy_propagation_arg.rs:37:9: 43:10
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}
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bb6: {
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_0 = const (); // scope 1 at $DIR/copy_propagation_arg.rs:37:9: 43:10
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goto -> bb25; // scope 1 at $DIR/copy_propagation_arg.rs:37:9: 43:10
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}
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bb7: {
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StorageLive(_12); // scope 1 at $DIR/copy_propagation_arg.rs:38:17: 38:19
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_20 = const false; // scope 1 at $DIR/copy_propagation_arg.rs:38:22: 38:24
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_21 = const true; // scope 1 at $DIR/copy_propagation_arg.rs:38:22: 38:24
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_12 = move _7; // scope 1 at $DIR/copy_propagation_arg.rs:38:22: 38:24
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StorageLive(_13); // scope 2 at $DIR/copy_propagation_arg.rs:39:16: 39:20
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StorageLive(_14); // scope 2 at $DIR/copy_propagation_arg.rs:39:18: 39:19
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_14 = const 2_usize; // scope 2 at $DIR/copy_propagation_arg.rs:39:18: 39:19
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_15 = Len((*_1)); // scope 2 at $DIR/copy_propagation_arg.rs:39:16: 39:20
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_16 = Lt(const 2_usize, _15); // scope 2 at $DIR/copy_propagation_arg.rs:39:16: 39:20
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assert(move _16, "index out of bounds: the len is {} but the index is {}", move _15, const 2_usize) -> [success: bb8, unwind: bb21]; // scope 2 at $DIR/copy_propagation_arg.rs:39:16: 39:20
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}
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bb8: {
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_13 = (*_1)[_14]; // scope 2 at $DIR/copy_propagation_arg.rs:39:16: 39:20
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StorageDead(_14); // scope 2 at $DIR/copy_propagation_arg.rs:39:19: 39:20
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switchInt(_13) -> [false: bb9, otherwise: bb10]; // scope 2 at $DIR/copy_propagation_arg.rs:39:13: 42:14
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}
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bb9: {
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_0 = const (); // scope 2 at $DIR/copy_propagation_arg.rs:39:13: 42:14
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goto -> bb23; // scope 2 at $DIR/copy_propagation_arg.rs:39:13: 42:14
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}
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bb10: {
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StorageLive(_17); // scope 2 at $DIR/copy_propagation_arg.rs:40:21: 40:23
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_21 = const false; // scope 2 at $DIR/copy_propagation_arg.rs:40:26: 40:28
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_17 = move _12; // scope 2 at $DIR/copy_propagation_arg.rs:40:26: 40:28
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StorageLive(_18); // scope 3 at $DIR/copy_propagation_arg.rs:41:17: 41:20
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_18 = &_17; // scope 3 at $DIR/copy_propagation_arg.rs:41:17: 41:20
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StorageDead(_18); // scope 3 at $DIR/copy_propagation_arg.rs:41:20: 41:21
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_0 = const (); // scope 2 at $DIR/copy_propagation_arg.rs:39:21: 42:14
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drop(_17) -> [return: bb11, unwind: bb21]; // scope 2 at $DIR/copy_propagation_arg.rs:42:13: 42:14
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}
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bb11: {
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StorageDead(_17); // scope 2 at $DIR/copy_propagation_arg.rs:42:13: 42:14
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goto -> bb23; // scope 2 at $DIR/copy_propagation_arg.rs:39:13: 42:14
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}
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bb12: {
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_21 = const false; // scope 1 at $DIR/copy_propagation_arg.rs:43:9: 43:10
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StorageDead(_12); // scope 1 at $DIR/copy_propagation_arg.rs:43:9: 43:10
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StorageDead(_13); // scope 1 at $DIR/copy_propagation_arg.rs:43:9: 43:10
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goto -> bb25; // scope 1 at $DIR/copy_propagation_arg.rs:37:9: 43:10
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}
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bb13: {
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_20 = const false; // scope 0 at $DIR/copy_propagation_arg.rs:44:5: 44:6
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StorageDead(_7); // scope 0 at $DIR/copy_propagation_arg.rs:44:5: 44:6
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StorageDead(_8); // scope 0 at $DIR/copy_propagation_arg.rs:44:5: 44:6
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goto -> bb14; // scope 0 at $DIR/copy_propagation_arg.rs:35:5: 44:6
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}
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bb14: {
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StorageDead(_3); // scope 0 at $DIR/copy_propagation_arg.rs:45:1: 45:2
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switchInt(_19) -> [false: bb15, otherwise: bb26]; // scope 0 at $DIR/copy_propagation_arg.rs:45:1: 45:2
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}
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bb15: {
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return; // scope 0 at $DIR/copy_propagation_arg.rs:45:2: 45:2
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}
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bb16 (cleanup): {
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_19 = const false; // scope 0 at $DIR/copy_propagation_arg.rs:45:1: 45:2
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drop(_2) -> bb1; // scope 0 at $DIR/copy_propagation_arg.rs:45:1: 45:2
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}
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bb17 (cleanup): {
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switchInt(_19) -> [false: bb1, otherwise: bb16]; // scope 0 at $DIR/copy_propagation_arg.rs:45:1: 45:2
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}
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bb18 (cleanup): {
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_20 = const false; // scope 0 at $DIR/copy_propagation_arg.rs:44:5: 44:6
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drop(_7) -> bb17; // scope 0 at $DIR/copy_propagation_arg.rs:44:5: 44:6
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}
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bb19 (cleanup): {
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switchInt(_20) -> [false: bb17, otherwise: bb18]; // scope 0 at $DIR/copy_propagation_arg.rs:44:5: 44:6
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}
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bb20 (cleanup): {
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_21 = const false; // scope 1 at $DIR/copy_propagation_arg.rs:43:9: 43:10
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drop(_12) -> bb19; // scope 1 at $DIR/copy_propagation_arg.rs:43:9: 43:10
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}
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bb21 (cleanup): {
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switchInt(_21) -> [false: bb19, otherwise: bb20]; // scope 1 at $DIR/copy_propagation_arg.rs:43:9: 43:10
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}
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bb22: {
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_21 = const false; // scope 1 at $DIR/copy_propagation_arg.rs:43:9: 43:10
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drop(_12) -> [return: bb12, unwind: bb19]; // scope 1 at $DIR/copy_propagation_arg.rs:43:9: 43:10
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}
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bb23: {
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switchInt(_21) -> [false: bb12, otherwise: bb22]; // scope 1 at $DIR/copy_propagation_arg.rs:43:9: 43:10
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}
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bb24: {
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_20 = const false; // scope 0 at $DIR/copy_propagation_arg.rs:44:5: 44:6
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drop(_7) -> [return: bb13, unwind: bb17]; // scope 0 at $DIR/copy_propagation_arg.rs:44:5: 44:6
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}
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bb25: {
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switchInt(_20) -> [false: bb13, otherwise: bb24]; // scope 0 at $DIR/copy_propagation_arg.rs:44:5: 44:6
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}
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bb26: {
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_19 = const false; // scope 0 at $DIR/copy_propagation_arg.rs:45:1: 45:2
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drop(_2) -> [return: bb15, unwind: bb1]; // scope 0 at $DIR/copy_propagation_arg.rs:45:1: 45:2
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}
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}
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‎src/test/mir-opt/copy_propagation_arg.rs

Lines changed: 15 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -30,10 +30,25 @@ fn arg_src(mut x: i32) -> i32 {
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y
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}
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// EMIT_MIR copy_propagation_arg.maybe.CopyPropagation.diff
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fn maybe(m: &[bool], s1: String) {
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if m[0] {
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let s2 = s1;
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if m[1] {
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let s3 = s2;
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if m[2] {
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let s4 = s3;
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&s4;
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}
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}
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}
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}
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fn main() {
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// Make sure the function actually gets instantiated.
3549
foo(0);
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bar(0);
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baz(0);
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arg_src(0);
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maybe(&[true, false, true], "Hello!".to_owned());
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}

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