diff options
4 files changed, 137 insertions, 0 deletions
diff --git a/compiler/rustc_mir_transform/src/jump_threading.rs b/compiler/rustc_mir_transform/src/jump_threading.rs index 2100f4b4a1a..96c52845a4a 100644 --- a/compiler/rustc_mir_transform/src/jump_threading.rs +++ b/compiler/rustc_mir_transform/src/jump_threading.rs @@ -509,6 +509,13 @@ impl<'tcx, 'a> TOFinder<'tcx, 'a> { BinOp::Ne => ScalarInt::FALSE, _ => return None, }; + if value.const_.ty().is_floating_point() { + // Floating point equality does not follow bit-patterns. + // -0.0 and NaN both have special rules for equality, + // and therefore we cannot use integer comparisons for them. + // Avoid handling them, though this could be extended in the future. + return None; + } let value = value.const_.normalize(self.tcx, self.param_env).try_to_scalar_int()?; let conds = conditions.map(self.arena, |c| Condition { value, diff --git a/tests/mir-opt/jump_threading.floats.JumpThreading.panic-abort.diff b/tests/mir-opt/jump_threading.floats.JumpThreading.panic-abort.diff new file mode 100644 index 00000000000..6ca37e96d29 --- /dev/null +++ b/tests/mir-opt/jump_threading.floats.JumpThreading.panic-abort.diff @@ -0,0 +1,59 @@ +- // MIR for `floats` before JumpThreading ++ // MIR for `floats` after JumpThreading + + fn floats() -> u32 { + let mut _0: u32; + let _1: f64; + let mut _2: bool; + let mut _3: bool; + let mut _4: f64; + scope 1 { + debug x => _1; + } + + bb0: { + StorageLive(_1); + StorageLive(_2); + _2 = const true; +- switchInt(move _2) -> [0: bb2, otherwise: bb1]; ++ goto -> bb1; + } + + bb1: { + _1 = const -0f64; + goto -> bb3; + } + + bb2: { + _1 = const 1f64; + goto -> bb3; + } + + bb3: { + StorageDead(_2); + StorageLive(_3); + StorageLive(_4); + _4 = _1; + _3 = Eq(move _4, const 0f64); + switchInt(move _3) -> [0: bb5, otherwise: bb4]; + } + + bb4: { + StorageDead(_4); + _0 = const 0_u32; + goto -> bb6; + } + + bb5: { + StorageDead(_4); + _0 = const 1_u32; + goto -> bb6; + } + + bb6: { + StorageDead(_3); + StorageDead(_1); + return; + } + } + diff --git a/tests/mir-opt/jump_threading.floats.JumpThreading.panic-unwind.diff b/tests/mir-opt/jump_threading.floats.JumpThreading.panic-unwind.diff new file mode 100644 index 00000000000..6ca37e96d29 --- /dev/null +++ b/tests/mir-opt/jump_threading.floats.JumpThreading.panic-unwind.diff @@ -0,0 +1,59 @@ +- // MIR for `floats` before JumpThreading ++ // MIR for `floats` after JumpThreading + + fn floats() -> u32 { + let mut _0: u32; + let _1: f64; + let mut _2: bool; + let mut _3: bool; + let mut _4: f64; + scope 1 { + debug x => _1; + } + + bb0: { + StorageLive(_1); + StorageLive(_2); + _2 = const true; +- switchInt(move _2) -> [0: bb2, otherwise: bb1]; ++ goto -> bb1; + } + + bb1: { + _1 = const -0f64; + goto -> bb3; + } + + bb2: { + _1 = const 1f64; + goto -> bb3; + } + + bb3: { + StorageDead(_2); + StorageLive(_3); + StorageLive(_4); + _4 = _1; + _3 = Eq(move _4, const 0f64); + switchInt(move _3) -> [0: bb5, otherwise: bb4]; + } + + bb4: { + StorageDead(_4); + _0 = const 0_u32; + goto -> bb6; + } + + bb5: { + StorageDead(_4); + _0 = const 1_u32; + goto -> bb6; + } + + bb6: { + StorageDead(_3); + StorageDead(_1); + return; + } + } + diff --git a/tests/mir-opt/jump_threading.rs b/tests/mir-opt/jump_threading.rs index de290c1ef44..e5d8525dcac 100644 --- a/tests/mir-opt/jump_threading.rs +++ b/tests/mir-opt/jump_threading.rs @@ -521,6 +521,16 @@ fn aggregate_copy() -> u32 { if c == 2 { b.0 } else { 13 } } +fn floats() -> u32 { + // CHECK-LABEL: fn floats( + // CHECK: switchInt( + + // Test for issue #128243, where float equality was assumed to be bitwise. + // When adding float support, it must be ensured that this continues working properly. + let x = if true { -0.0 } else { 1.0 }; + if x == 0.0 { 0 } else { 1 } +} + fn main() { // CHECK-LABEL: fn main( too_complex(Ok(0)); @@ -535,6 +545,7 @@ fn main() { disappearing_bb(7); aggregate(7); assume(7, false); + floats(); } // EMIT_MIR jump_threading.too_complex.JumpThreading.diff @@ -550,3 +561,4 @@ fn main() { // EMIT_MIR jump_threading.aggregate.JumpThreading.diff // EMIT_MIR jump_threading.assume.JumpThreading.diff // EMIT_MIR jump_threading.aggregate_copy.JumpThreading.diff +// EMIT_MIR jump_threading.floats.JumpThreading.diff |