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-rw-r--r--tests/mir-opt/jump_threading.rs480
1 files changed, 480 insertions, 0 deletions
diff --git a/tests/mir-opt/jump_threading.rs b/tests/mir-opt/jump_threading.rs
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+++ b/tests/mir-opt/jump_threading.rs
@@ -0,0 +1,480 @@
+// unit-test: JumpThreading
+// compile-flags: -Zmir-enable-passes=+Inline
+// EMIT_MIR_FOR_EACH_PANIC_STRATEGY
+
+#![feature(control_flow_enum)]
+#![feature(try_trait_v2)]
+#![feature(custom_mir, core_intrinsics, rustc_attrs)]
+
+use std::intrinsics::mir::*;
+use std::ops::ControlFlow;
+
+fn too_complex(x: Result<i32, usize>) -> Option<i32> {
+ // CHECK-LABEL: fn too_complex(
+ // CHECK: bb0: {
+ // CHECK: switchInt(move {{_.*}}) -> [0: bb3, 1: bb1, otherwise: bb2];
+ // CHECK: bb1: {
+ // CHECK: [[controlflow:_.*]] = ControlFlow::<usize, i32>::Break(
+ // CHECK: goto -> bb8;
+ // CHECK: bb2: {
+ // CHECK: unreachable;
+ // CHECK: bb3: {
+ // CHECK: [[controlflow]] = ControlFlow::<usize, i32>::Continue(
+ // CHECK: goto -> bb4;
+ // CHECK: bb4: {
+ // CHECK: goto -> bb6;
+ // CHECK: bb5: {
+ // CHECK: {{_.*}} = (([[controlflow]] as Break).0: usize);
+ // CHECK: _0 = Option::<i32>::None;
+ // CHECK: goto -> bb7;
+ // CHECK: bb6: {
+ // CHECK: {{_.*}} = (([[controlflow]] as Continue).0: i32);
+ // CHECK: _0 = Option::<i32>::Some(
+ // CHECK: goto -> bb7;
+ // CHECK: bb7: {
+ // CHECK: return;
+ // CHECK: bb8: {
+ // CHECK: goto -> bb5;
+ match {
+ match x {
+ Ok(v) => ControlFlow::Continue(v),
+ Err(r) => ControlFlow::Break(r),
+ }
+ } {
+ ControlFlow::Continue(v) => Some(v),
+ ControlFlow::Break(r) => None,
+ }
+}
+
+fn identity(x: Result<i32, i32>) -> Result<i32, i32> {
+ // CHECK-LABEL: fn identity(
+ // CHECK: bb0: {
+ // CHECK: [[x:_.*]] = _1;
+ // CHECK: switchInt(move {{_.*}}) -> [0: bb8, 1: bb6, otherwise: bb7];
+ // CHECK: bb1: {
+ // CHECK: goto -> bb2;
+ // CHECK: bb2: {
+ // CHECK: {{_.*}} = (([[controlflow:_.*]] as Continue).0: i32);
+ // CHECK: _0 = Result::<i32, i32>::Ok(
+ // CHECK: goto -> bb5;
+ // CHECK: bb3: {
+ // CHECK: unreachable;
+ // CHECK: bb4: {
+ // CHECK: {{_.*}} = (([[controlflow]] as Break).0: std::result::Result<std::convert::Infallible, i32>);
+ // CHECK: _0 = Result::<i32, i32>::Err(
+ // CHECK: goto -> bb5;
+ // CHECK: bb5: {
+ // CHECK: return;
+ // CHECK: bb6: {
+ // CHECK: {{_.*}} = move (([[x]] as Err).0: i32);
+ // CHECK: [[controlflow]] = ControlFlow::<Result<Infallible, i32>, i32>::Break(
+ // CHECK: goto -> bb9;
+ // CHECK: bb7: {
+ // CHECK: unreachable;
+ // CHECK: bb8: {
+ // CHECK: {{_.*}} = move (([[x]] as Ok).0: i32);
+ // CHECK: [[controlflow]] = ControlFlow::<Result<Infallible, i32>, i32>::Continue(
+ // CHECK: goto -> bb1;
+ // CHECK: bb9: {
+ // CHECK: goto -> bb4;
+ Ok(x?)
+}
+
+enum DFA {
+ A,
+ B,
+ C,
+ D,
+}
+
+/// Check that we do not thread through a loop header,
+/// to avoid creating an irreducible CFG.
+fn dfa() {
+ // CHECK-LABEL: fn dfa(
+ // CHECK: bb0: {
+ // CHECK: {{_.*}} = DFA::A;
+ // CHECK: goto -> bb1;
+ // CHECK: bb1: {
+ // CHECK: switchInt({{.*}}) -> [0: bb4, 1: bb5, 2: bb6, 3: bb2, otherwise: bb3];
+ // CHECK: bb2: {
+ // CHECK: return;
+ // CHECK: bb3: {
+ // CHECK: unreachable;
+ // CHECK: bb4: {
+ // CHECK: {{_.*}} = DFA::B;
+ // CHECK: goto -> bb1;
+ // CHECK: bb5: {
+ // CHECK: {{_.*}} = DFA::C;
+ // CHECK: goto -> bb1;
+ // CHECK: bb6: {
+ // CHECK: {{_.*}} = DFA::D;
+ // CHECK: goto -> bb1;
+ let mut state = DFA::A;
+ loop {
+ match state {
+ DFA::A => state = DFA::B,
+ DFA::B => state = DFA::C,
+ DFA::C => state = DFA::D,
+ DFA::D => return,
+ }
+ }
+}
+
+#[repr(u8)]
+enum CustomDiscr {
+ A = 35,
+ B = 73,
+ C = 99,
+}
+
+/// Verify that we correctly match the discriminant value, and not its index.
+fn custom_discr(x: bool) -> u8 {
+ // CHECK-LABEL: fn custom_discr(
+ // CHECK: bb0: {
+ // CHECK: switchInt({{.*}}) -> [0: bb2, otherwise: bb1];
+ // CHECK: bb1: {
+ // CHECK: {{_.*}} = CustomDiscr::A;
+ // CHECK: goto -> bb7;
+ // CHECK: bb2: {
+ // CHECK: {{_.*}} = CustomDiscr::B;
+ // CHECK: goto -> bb3;
+ // CHECK: bb3: {
+ // CHECK: goto -> bb4;
+ // CHECK: bb4: {
+ // CHECK: _0 = const 13_u8;
+ // CHECK: goto -> bb6;
+ // CHECK: bb5: {
+ // CHECK: _0 = const 5_u8;
+ // CHECK: goto -> bb6;
+ // CHECK: bb6: {
+ // CHECK: return;
+ // CHECK: bb7: {
+ // CHECK: goto -> bb5;
+ match if x { CustomDiscr::A } else { CustomDiscr::B } {
+ CustomDiscr::A => 5,
+ _ => 13,
+ }
+}
+
+#[custom_mir(dialect = "runtime", phase = "post-cleanup")]
+fn multiple_match(x: u8) -> u8 {
+ // CHECK-LABEL: fn multiple_match(
+ mir!(
+ {
+ // CHECK: bb0: {
+ // CHECK: switchInt([[x:_.*]]) -> [3: bb1, otherwise: bb2];
+ match x { 3 => bb1, _ => bb2 }
+ }
+ bb1 = {
+ // We know `x == 3`, so we can take `bb3`.
+ // CHECK: bb1: {
+ // CHECK: {{_.*}} = [[x]];
+ // CHECK: goto -> bb3;
+ let y = x;
+ match y { 3 => bb3, _ => bb4 }
+ }
+ bb2 = {
+ // We know `x != 3`, so we can take `bb6`.
+ // CHECK: bb2: {
+ // CHECK: [[z:_.*]] = [[x]];
+ // CHECK: goto -> bb6;
+ let z = x;
+ match z { 3 => bb5, _ => bb6 }
+ }
+ bb3 = {
+ // CHECK: bb3: {
+ // CHECK: _0 = const 5_u8;
+ // CHECK: return;
+ RET = 5;
+ Return()
+ }
+ bb4 = {
+ // CHECK: bb4: {
+ // CHECK: _0 = const 7_u8;
+ // CHECK: return;
+ RET = 7;
+ Return()
+ }
+ bb5 = {
+ // CHECK: bb5: {
+ // CHECK: _0 = const 9_u8;
+ // CHECK: return;
+ RET = 9;
+ Return()
+ }
+ bb6 = {
+ // We know `z != 3`, so we CANNOT take `bb7`.
+ // CHECK: bb6: {
+ // CHECK: switchInt([[z]]) -> [1: bb7, otherwise: bb8];
+ match z { 1 => bb7, _ => bb8 }
+ }
+ bb7 = {
+ // CHECK: bb7: {
+ // CHECK: _0 = const 9_u8;
+ // CHECK: return;
+ RET = 9;
+ Return()
+ }
+ bb8 = {
+ // CHECK: bb8: {
+ // CHECK: _0 = const 11_u8;
+ // CHECK: return;
+ RET = 11;
+ Return()
+ }
+ )
+}
+
+/// Both 1-3-4 and 2-3-4 are threadable. As 1 and 2 are the only predecessors of 3,
+/// verify that we only thread the 3-4 part.
+#[custom_mir(dialect = "runtime", phase = "post-cleanup")]
+fn duplicate_chain(x: bool) -> u8 {
+ // CHECK-LABEL: fn duplicate_chain(
+ mir!(
+ let a: u8;
+ {
+ // CHECK: bb0: {
+ // CHECK: switchInt({{.*}}) -> [1: bb1, otherwise: bb2];
+ match x { true => bb1, _ => bb2 }
+ }
+ bb1 = {
+ // CHECK: bb1: {
+ // CHECK: [[a:_.*]] = const 5_u8;
+ // CHECK: goto -> bb3;
+ a = 5;
+ Goto(bb3)
+ }
+ bb2 = {
+ // CHECK: bb2: {
+ // CHECK: [[a]] = const 5_u8;
+ // CHECK: goto -> bb3;
+ a = 5;
+ Goto(bb3)
+ }
+ bb3 = {
+ // CHECK: bb3: {
+ // CHECK: {{_.*}} = const 13_i32;
+ // CHECK: goto -> bb4;
+ let b = 13;
+ Goto(bb4)
+ }
+ bb4 = {
+ // CHECK: bb4: {
+ // CHECK: {{_.*}} = const 15_i32;
+ // CHECK-NOT: switchInt(
+ // CHECK: goto -> bb5;
+ let c = 15;
+ match a { 5 => bb5, _ => bb6 }
+ }
+ bb5 = {
+ // CHECK: bb5: {
+ // CHECK: _0 = const 7_u8;
+ // CHECK: return;
+ RET = 7;
+ Return()
+ }
+ bb6 = {
+ // CHECK: bb6: {
+ // CHECK: _0 = const 9_u8;
+ // CHECK: return;
+ RET = 9;
+ Return()
+ }
+ )
+}
+
+#[rustc_layout_scalar_valid_range_start(1)]
+#[rustc_nonnull_optimization_guaranteed]
+struct NonZeroUsize(usize);
+
+/// Verify that we correctly discard threads that may mutate a discriminant by aliasing.
+#[custom_mir(dialect = "runtime", phase = "post-cleanup")]
+fn mutate_discriminant() -> u8 {
+ // CHECK-LABEL: fn mutate_discriminant(
+ // CHECK-NOT: goto -> {{bb.*}};
+ // CHECK: switchInt(
+ // CHECK-NOT: goto -> {{bb.*}};
+ mir!(
+ let x: Option<NonZeroUsize>;
+ {
+ SetDiscriminant(x, 1);
+ // This assignment overwrites the niche in which the discriminant is stored.
+ place!(Field(Field(Variant(x, 1), 0), 0)) = 0_usize;
+ // So we cannot know the value of this discriminant.
+ let a = Discriminant(x);
+ match a {
+ 0 => bb1,
+ _ => bad,
+ }
+ }
+ bb1 = {
+ RET = 1;
+ Return()
+ }
+ bad = {
+ RET = 2;
+ Unreachable()
+ }
+ )
+}
+
+/// Verify that we do not try to reason when there are mutable pointers involved.
+fn mutable_ref() -> bool {
+ // CHECK-LABEL: fn mutable_ref(
+ // CHECK-NOT: goto -> {{bb.*}};
+ // CHECK: switchInt(
+ // CHECK: goto -> [[bbret:bb.*]];
+ // CHECK: goto -> [[bbret]];
+ // CHECK: [[bbret]]: {
+ // CHECK-NOT: {{bb.*}}: {
+ // CHECK: return;
+ let mut x = 5;
+ let a = std::ptr::addr_of_mut!(x);
+ x = 7;
+ unsafe { *a = 8 };
+ if x == 7 {
+ true
+ } else {
+ false
+ }
+}
+
+/// This function has 2 TOs: 1-3-4 and 0-1-3-4-6.
+/// We verify that the second TO does not modify 3 once the first has been applied.
+#[custom_mir(dialect = "runtime", phase = "post-cleanup")]
+fn renumbered_bb(x: bool) -> u8 {
+ // CHECK-LABEL: fn renumbered_bb(
+ mir!(
+ let a: bool;
+ let b: bool;
+ {
+ // CHECK: bb0: {
+ // CHECK: switchInt({{.*}}) -> [1: bb1, otherwise: bb2];
+ b = false;
+ match x { true => bb1, _ => bb2 }
+ }
+ bb1 = {
+ // CHECK: bb1: {
+ // CHECK: goto -> bb8;
+ a = false;
+ Goto(bb3)
+ }
+ bb2 = {
+ // CHECK: bb2: {
+ // CHECK: goto -> bb3;
+ a = x;
+ b = x;
+ Goto(bb3)
+ }
+ bb3 = {
+ // CHECK: bb3: {
+ // CHECK: switchInt({{.*}}) -> [0: bb4, otherwise: bb5];
+ match a { false => bb4, _ => bb5 }
+ }
+ bb4 = {
+ // CHECK: bb4: {
+ // CHECK: switchInt({{.*}}) -> [0: bb6, otherwise: bb7];
+ match b { false => bb6, _ => bb7 }
+ }
+ bb5 = {
+ // CHECK: bb5: {
+ // CHECK: _0 = const 7_u8;
+ RET = 7;
+ Return()
+ }
+ bb6 = {
+ // CHECK: bb6: {
+ // CHECK: _0 = const 9_u8;
+ RET = 9;
+ Return()
+ }
+ bb7 = {
+ // CHECK: bb7: {
+ // CHECK: _0 = const 11_u8;
+ RET = 11;
+ Return()
+ }
+ // Duplicate of bb3.
+ // CHECK: bb8: {
+ // CHECK-NEXT: goto -> bb9;
+ // Duplicate of bb4.
+ // CHECK: bb9: {
+ // CHECK-NEXT: goto -> bb6;
+ )
+}
+
+/// This function has 3 TOs: 1-4-5, 0-1-4-7-5-8 and 3-4-7-5-6
+/// After applying the first TO, we create bb9 to replace 4, and rename 1-4 edge by 1-9. The
+/// second TO may try to thread non-existing edge 9-4.
+/// This test verifies that we preserve semantics by bailing out of this second TO.
+#[custom_mir(dialect = "runtime", phase = "post-cleanup")]
+fn disappearing_bb(x: u8) -> u8 {
+ // CHECK-LABEL: fn disappearing_bb(
+ mir!(
+ let a: bool;
+ let b: bool;
+ {
+ a = true;
+ b = true;
+ match x { 0 => bb3, 1 => bb3, 2 => bb1, _ => bb2 }
+ }
+ bb1 = {
+ // CHECK: bb1: {
+ // CHECK: goto -> bb9;
+ b = false;
+ Goto(bb4)
+ }
+ bb2 = {
+ Unreachable()
+ }
+ bb3 = {
+ // CHECK: bb3: {
+ // CHECK: goto -> bb10;
+ a = false;
+ Goto(bb4)
+ }
+ bb4 = {
+ match b { false => bb5, _ => bb7 }
+ }
+ bb5 = {
+ match a { false => bb6, _ => bb8 }
+ }
+ bb6 = {
+ Return()
+ }
+ bb7 = {
+ Goto(bb5)
+ }
+ bb8 = {
+ Goto(bb6)
+ }
+ // CHECK: bb9: {
+ // CHECK: goto -> bb5;
+ // CHECK: bb10: {
+ // CHECK: goto -> bb6;
+ )
+}
+
+fn main() {
+ too_complex(Ok(0));
+ identity(Ok(0));
+ custom_discr(false);
+ dfa();
+ multiple_match(5);
+ duplicate_chain(false);
+ mutate_discriminant();
+ mutable_ref();
+ renumbered_bb(true);
+ disappearing_bb(7);
+}
+
+// EMIT_MIR jump_threading.too_complex.JumpThreading.diff
+// EMIT_MIR jump_threading.identity.JumpThreading.diff
+// EMIT_MIR jump_threading.custom_discr.JumpThreading.diff
+// EMIT_MIR jump_threading.dfa.JumpThreading.diff
+// EMIT_MIR jump_threading.multiple_match.JumpThreading.diff
+// EMIT_MIR jump_threading.duplicate_chain.JumpThreading.diff
+// EMIT_MIR jump_threading.mutate_discriminant.JumpThreading.diff
+// EMIT_MIR jump_threading.mutable_ref.JumpThreading.diff
+// EMIT_MIR jump_threading.renumbered_bb.JumpThreading.diff
+// EMIT_MIR jump_threading.disappearing_bb.JumpThreading.diff
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