f305e18804
Jump threading stores values as `u128` (`ScalarInt`) and does its comparisons for equality as integer comparisons. This works great for integers. Sadly, not everything is an integer. Floats famously have wonky equality semantcs, with `NaN!=NaN` and `0.0 == -0.0`. This does not match our beautiful integer bitpattern equality and therefore causes things to go horribly wrong. While jump threading could be extended to support floats by remembering that they're floats in the value state and handling them properly, it's signficantly easier to just disable it for now.
60 lines
1.1 KiB
Diff
60 lines
1.1 KiB
Diff
- // MIR for `floats` before JumpThreading
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+ // MIR for `floats` after JumpThreading
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fn floats() -> u32 {
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let mut _0: u32;
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let _1: f64;
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let mut _2: bool;
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let mut _3: bool;
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let mut _4: f64;
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scope 1 {
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debug x => _1;
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}
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bb0: {
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StorageLive(_1);
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StorageLive(_2);
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_2 = const true;
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- switchInt(move _2) -> [0: bb2, otherwise: bb1];
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+ goto -> bb1;
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}
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bb1: {
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_1 = const -0f64;
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goto -> bb3;
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}
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bb2: {
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_1 = const 1f64;
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goto -> bb3;
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}
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bb3: {
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StorageDead(_2);
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StorageLive(_3);
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StorageLive(_4);
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_4 = _1;
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_3 = Eq(move _4, const 0f64);
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switchInt(move _3) -> [0: bb5, otherwise: bb4];
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}
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bb4: {
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StorageDead(_4);
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_0 = const 0_u32;
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goto -> bb6;
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}
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bb5: {
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StorageDead(_4);
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_0 = const 1_u32;
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goto -> bb6;
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}
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bb6: {
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StorageDead(_3);
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StorageDead(_1);
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return;
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}
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}
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