Replace ConstProp by DataflowConstProp.

Author: cjgillot

compiler/rustc_mir_transform/src/const_prop.rs

@@ -24,11 +24,11 @@ use crate::MirPass;
 const BLOCK_LIMIT: usize = 100;
 const PLACE_LIMIT: usize = 100;
 
-pub struct DataflowConstProp;
+pub struct ConstProp;
 
-impl<'tcx> MirPass<'tcx> for DataflowConstProp {
+impl<'tcx> MirPass<'tcx> for ConstProp {
     fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
-        sess.mir_opt_level() >= 3
+        sess.mir_opt_level() >= 2
     }
 
     #[instrument(skip_all level = "debug")]

compiler/rustc_mir_transform/src/dataflow_const_prop.rs

@@ -549,8 +549,7 @@ fn run_optimization_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
             // destroy the SSA property. It should still happen before const-propagation, so the
             // latter pass will leverage the created opportunities.
             &separate_const_switch::SeparateConstSwitch,
-            &const_prop::ConstProp,
-            &dataflow_const_prop::DataflowConstProp,
+            &dataflow_const_prop::ConstProp,
             //
             // Const-prop runs unconditionally, but doesn't mutate the MIR at mir-opt-level=0.
             &const_debuginfo::ConstDebugInfo,

compiler/rustc_mir_transform/src/lib.rs

@@ -28,7 +28,7 @@
 
       bb1: {
 -         _1 = _2[_3];
-+         _1 = const 2_u32;
++         _1 = _2[2 of 3];
           StorageDead(_3);
           StorageDead(_2);
           _0 = const ();

tests/mir-opt/const_prop/array_index.main.ConstProp.32bit.panic-abort.diff

@@ -28,7 +28,7 @@
 
       bb1: {
 -         _1 = _2[_3];
-+         _1 = const 2_u32;
++         _1 = _2[2 of 3];
           StorageDead(_3);
           StorageDead(_2);
           _0 = const ();

tests/mir-opt/const_prop/array_index.main.ConstProp.32bit.panic-unwind.diff

@@ -28,7 +28,7 @@
 
       bb1: {
 -         _1 = _2[_3];
-+         _1 = const 2_u32;
++         _1 = _2[2 of 3];
           StorageDead(_3);
           StorageDead(_2);
           _0 = const ();

tests/mir-opt/const_prop/array_index.main.ConstProp.64bit.panic-abort.diff

@@ -28,7 +28,7 @@
 
       bb1: {
 -         _1 = _2[_3];
-+         _1 = const 2_u32;
++         _1 = _2[2 of 3];
           StorageDead(_3);
           StorageDead(_2);
           _0 = const ();

tests/mir-opt/const_prop/array_index.main.ConstProp.64bit.panic-unwind.diff

@@ -34,11 +34,12 @@
           StorageLive(_5);
           StorageLive(_6);
           _6 = const 3_usize;
-          _7 = Len((*_1));
+-         _7 = Len((*_1));
 -         _8 = Lt(_6, _7);
 -         assert(move _8, "index out of bounds: the length is {} but the index is {}", move _7, _6) -> [success: bb1, unwind unreachable];
-+         _8 = Lt(const 3_usize, _7);
-+         assert(move _8, "index out of bounds: the length is {} but the index is {}", move _7, const 3_usize) -> [success: bb1, unwind unreachable];
++         _7 = const 3_usize;
++         _8 = const false;
++         assert(const false, "index out of bounds: the length is {} but the index is {}", const 3_usize, const 3_usize) -> [success: bb1, unwind unreachable];
       }
 
       bb1: {

tests/mir-opt/const_prop/bad_op_unsafe_oob_for_slices.main.ConstProp.32bit.panic-abort.diff

@@ -34,11 +34,12 @@
           StorageLive(_5);
           StorageLive(_6);
           _6 = const 3_usize;
-          _7 = Len((*_1));
+-         _7 = Len((*_1));
 -         _8 = Lt(_6, _7);
 -         assert(move _8, "index out of bounds: the length is {} but the index is {}", move _7, _6) -> [success: bb1, unwind continue];
-+         _8 = Lt(const 3_usize, _7);
-+         assert(move _8, "index out of bounds: the length is {} but the index is {}", move _7, const 3_usize) -> [success: bb1, unwind continue];
++         _7 = const 3_usize;
++         _8 = const false;
++         assert(const false, "index out of bounds: the length is {} but the index is {}", const 3_usize, const 3_usize) -> [success: bb1, unwind continue];
       }
 
       bb1: {

tests/mir-opt/const_prop/bad_op_unsafe_oob_for_slices.main.ConstProp.32bit.panic-unwind.diff

@@ -34,11 +34,12 @@
           StorageLive(_5);
           StorageLive(_6);
           _6 = const 3_usize;
-          _7 = Len((*_1));
+-         _7 = Len((*_1));
 -         _8 = Lt(_6, _7);
 -         assert(move _8, "index out of bounds: the length is {} but the index is {}", move _7, _6) -> [success: bb1, unwind unreachable];
-+         _8 = Lt(const 3_usize, _7);
-+         assert(move _8, "index out of bounds: the length is {} but the index is {}", move _7, const 3_usize) -> [success: bb1, unwind unreachable];
++         _7 = const 3_usize;
++         _8 = const false;
++         assert(const false, "index out of bounds: the length is {} but the index is {}", const 3_usize, const 3_usize) -> [success: bb1, unwind unreachable];
       }
 
       bb1: {

tests/mir-opt/const_prop/bad_op_unsafe_oob_for_slices.main.ConstProp.64bit.panic-abort.diff

@@ -34,11 +34,12 @@
           StorageLive(_5);
           StorageLive(_6);
           _6 = const 3_usize;
-          _7 = Len((*_1));
+-         _7 = Len((*_1));
 -         _8 = Lt(_6, _7);
 -         assert(move _8, "index out of bounds: the length is {} but the index is {}", move _7, _6) -> [success: bb1, unwind continue];
-+         _8 = Lt(const 3_usize, _7);
-+         assert(move _8, "index out of bounds: the length is {} but the index is {}", move _7, const 3_usize) -> [success: bb1, unwind continue];
++         _7 = const 3_usize;
++         _8 = const false;
++         assert(const false, "index out of bounds: the length is {} but the index is {}", const 3_usize, const 3_usize) -> [success: bb1, unwind continue];
       }
 
       bb1: {

tests/mir-opt/const_prop/bad_op_unsafe_oob_for_slices.main.ConstProp.64bit.panic-unwind.diff

@@ -4,11 +4,21 @@
   fn main() -> () {
       let mut _0: ();
       let _1: u32;
+      let mut _5: u8;
+      let mut _6: i32;
       scope 1 {
           debug x => _1;
           let _2: u8;
           scope 2 {
               debug y => _2;
+              let _3: i32;
+              scope 3 {
+                  debug a => _3;
+                  let _4: u8;
+                  scope 4 {
+                      debug b => _4;
+                  }
+              }
           }
       }
 
@@ -19,7 +29,22 @@
           StorageLive(_2);
 -         _2 = const 42_u32 as u8 (IntToInt);
 +         _2 = const 42_u8;
+          StorageLive(_3);
+          _3 = const 257_i32;
+          StorageLive(_4);
+          StorageLive(_5);
+          StorageLive(_6);
+-         _6 = _3;
+-         _5 = move _6 as u8 (IntToInt);
++         _6 = const 257_i32;
++         _5 = const 1_u8;
+          StorageDead(_6);
+-         _4 = Add(move _5, const 1_u8);
++         _4 = const 2_u8;
+          StorageDead(_5);
           _0 = const ();
+          StorageDead(_4);
+          StorageDead(_3);
           StorageDead(_2);
           StorageDead(_1);
           return;

tests/mir-opt/const_prop/cast.main.ConstProp.diff

@@ -3,6 +3,8 @@
 
 fn main() {
     let x = 42u8 as u32;
-
     let y = 42u32 as u8;
+
+    let a = 257;
+    let b = a as u8 + 1;
 }

tests/mir-opt/const_prop/cast.rs

@@ -1,5 +1,5 @@
-- // MIR for `main` before DataflowConstProp
-+ // MIR for `main` after DataflowConstProp
+- // MIR for `main` before ConstProp
++ // MIR for `main` after ConstProp
 
   fn main() -> () {
       let mut _0: ();

tests/mir-opt/dataflow-const-prop/checked.main.DataflowConstProp.panic-abort.diff renamed to tests/mir-opt/const_prop/checked.main.ConstProp.panic-abort.diff

@@ -1,5 +1,5 @@
-- // MIR for `main` before DataflowConstProp
-+ // MIR for `main` after DataflowConstProp
+- // MIR for `main` before ConstProp
++ // MIR for `main` after ConstProp
 
   fn main() -> () {
       let mut _0: ();

tests/mir-opt/dataflow-const-prop/checked.main.DataflowConstProp.panic-unwind.diff renamed to tests/mir-opt/const_prop/checked.main.ConstProp.panic-unwind.diff

@@ -1,8 +1,8 @@
 // EMIT_MIR_FOR_EACH_PANIC_STRATEGY
-// unit-test: DataflowConstProp
+// unit-test: ConstProp
 // compile-flags: -Coverflow-checks=on
 
-// EMIT_MIR checked.main.DataflowConstProp.diff
+// EMIT_MIR checked.main.ConstProp.diff
 #[allow(arithmetic_overflow)]
 fn main() {
     let a = 1;

tests/mir-opt/dataflow-const-prop/checked.rs renamed to tests/mir-opt/const_prop/checked.rs

@@ -11,9 +11,8 @@
 
       bb0: {
           StorageLive(_1);
--         _2 = CheckedAdd(const 1_u32, const 1_u32);
+          _2 = CheckedAdd(const 1_u32, const 1_u32);
 -         assert(!move (_2.1: bool), "attempt to compute `{} + {}`, which would overflow", const 1_u32, const 1_u32) -> [success: bb1, unwind unreachable];
-+         _2 = const (2_u32, false);
 +         assert(!const false, "attempt to compute `{} + {}`, which would overflow", const 1_u32, const 1_u32) -> [success: bb1, unwind unreachable];
       }
 

tests/mir-opt/const_prop/checked_add.main.ConstProp.panic-abort.diff

@@ -11,9 +11,8 @@
 
       bb0: {
           StorageLive(_1);
--         _2 = CheckedAdd(const 1_u32, const 1_u32);
+          _2 = CheckedAdd(const 1_u32, const 1_u32);
 -         assert(!move (_2.1: bool), "attempt to compute `{} + {}`, which would overflow", const 1_u32, const 1_u32) -> [success: bb1, unwind continue];
-+         _2 = const (2_u32, false);
 +         assert(!const false, "attempt to compute `{} + {}`, which would overflow", const 1_u32, const 1_u32) -> [success: bb1, unwind continue];
       }
 

tests/mir-opt/const_prop/checked_add.main.ConstProp.panic-unwind.diff

@@ -8,9 +8,8 @@
 
       bb0: {
           StorageLive(_1);
--         _1 = const _;
+          _1 = const _;
 -         switchInt(move _1) -> [0: bb2, otherwise: bb1];
-+         _1 = const false;
 +         switchInt(const false) -> [0: bb2, otherwise: bb1];
       }
 

tests/mir-opt/const_allocation.main.ConstProp.after.32bit.mir renamed to tests/mir-opt/const_prop/const_allocation.main.ConstProp.after.32bit.mir

@@ -8,9 +8,8 @@
 
       bb0: {
           StorageLive(_1);
--         _1 = const _;
+          _1 = const _;
 -         switchInt(move _1) -> [0: bb2, otherwise: bb1];
-+         _1 = const false;
 +         switchInt(const false) -> [0: bb2, otherwise: bb1];
       }
 

tests/mir-opt/const_allocation.main.ConstProp.after.64bit.mir renamed to tests/mir-opt/const_prop/const_allocation.main.ConstProp.after.64bit.mir

@@ -17,10 +17,9 @@
           StorageLive(_1);
           StorageLive(_2);
           StorageLive(_3);
--         _3 = Option::<bool>::Some(const true);
+          _3 = Option::<bool>::Some(const true);
 -         _4 = discriminant(_3);
 -         switchInt(move _4) -> [1: bb1, otherwise: bb3];
-+         _3 = const Option::<bool>::Some(true);
 +         _4 = const 1_isize;
 +         switchInt(const 1_isize) -> [1: bb1, otherwise: bb3];
       }
@@ -41,7 +40,8 @@
       }
 
       bb4: {
-          _1 = Add(move _2, const 0_i32);
+-         _1 = Add(move _2, const 0_i32);
++         _1 = const 42_i32;
           StorageDead(_2);
           StorageDead(_3);
           _0 = const ();

tests/mir-opt/const_allocation.rs renamed to tests/mir-opt/const_prop/const_allocation.rs

@@ -17,10 +17,9 @@
           StorageLive(_1);
           StorageLive(_2);
           StorageLive(_3);
--         _3 = Option::<bool>::Some(const true);
+          _3 = Option::<bool>::Some(const true);
 -         _4 = discriminant(_3);
 -         switchInt(move _4) -> [1: bb1, otherwise: bb3];
-+         _3 = const Option::<bool>::Some(true);
 +         _4 = const 1_isize;
 +         switchInt(const 1_isize) -> [1: bb1, otherwise: bb3];
       }
@@ -41,7 +40,8 @@
       }
 
       bb4: {
-          _1 = Add(move _2, const 0_i32);
+-         _1 = Add(move _2, const 0_i32);
++         _1 = const 42_i32;
           StorageDead(_2);
           StorageDead(_3);
           _0 = const ();

tests/mir-opt/const_allocation2.main.ConstProp.after.32bit.mir renamed to tests/mir-opt/const_prop/const_allocation2.main.ConstProp.after.32bit.mir

@@ -1,5 +1,5 @@
-- // MIR for `multiple` before DataflowConstProp
-+ // MIR for `multiple` after DataflowConstProp
+- // MIR for `multiple` before ConstProp
++ // MIR for `multiple` after ConstProp
 
   fn multiple(_1: bool, _2: u8) -> () {
       debug x => _1;

tests/mir-opt/const_allocation2.main.ConstProp.after.64bit.mir renamed to tests/mir-opt/const_prop/const_allocation2.main.ConstProp.after.64bit.mir

@@ -1,5 +1,5 @@
-- // MIR for `mutate_discriminant` before DataflowConstProp
-+ // MIR for `mutate_discriminant` after DataflowConstProp
+- // MIR for `mutate_discriminant` before ConstProp
++ // MIR for `mutate_discriminant` after ConstProp
 
   fn mutate_discriminant() -> u8 {
       let mut _0: u8;

tests/mir-opt/const_allocation2.rs renamed to tests/mir-opt/const_prop/const_allocation2.rs

@@ -1,4 +1,4 @@
-// unit-test: DataflowConstProp
+// unit-test: ConstProp
 
 #![feature(custom_mir, core_intrinsics, rustc_attrs)]
 
@@ -9,7 +9,7 @@ enum E {
     V2(i32)
 }
 
-// EMIT_MIR enum.simple.DataflowConstProp.diff
+// EMIT_MIR enum.simple.ConstProp.diff
 fn simple() {
     let e = E::V1(0);
     let x = match e { E::V1(x) => x, E::V2(x) => x };
@@ -19,7 +19,7 @@ fn simple() {
 #[rustc_nonnull_optimization_guaranteed]
 struct NonZeroUsize(usize);
 
-// EMIT_MIR enum.mutate_discriminant.DataflowConstProp.diff
+// EMIT_MIR enum.mutate_discriminant.ConstProp.diff
 #[custom_mir(dialect = "runtime", phase = "post-cleanup")]
 fn mutate_discriminant() -> u8 {
     mir!(
@@ -46,7 +46,7 @@ fn mutate_discriminant() -> u8 {
     )
 }
 
-// EMIT_MIR enum.multiple.DataflowConstProp.diff
+// EMIT_MIR enum.multiple.ConstProp.diff
 fn multiple(x: bool, i: u8) {
     let e = if x {
         Some(i)

tests/mir-opt/const_allocation3.main.ConstProp.after.32bit.mir renamed to tests/mir-opt/const_prop/const_allocation3.main.ConstProp.after.32bit.mir

@@ -1,5 +1,5 @@
-- // MIR for `simple` before DataflowConstProp
-+ // MIR for `simple` after DataflowConstProp
+- // MIR for `simple` before ConstProp
++ // MIR for `simple` after ConstProp
 
   fn simple() -> () {
       let mut _0: ();

tests/mir-opt/const_allocation3.main.ConstProp.after.64bit.mir renamed to tests/mir-opt/const_prop/const_allocation3.main.ConstProp.after.64bit.mir

@@ -1,5 +1,5 @@
-- // MIR for `main` before DataflowConstProp
-+ // MIR for `main` after DataflowConstProp
+- // MIR for `main` before ConstProp
++ // MIR for `main` after ConstProp
 
   fn main() -> () {
       let mut _0: ();

tests/mir-opt/const_allocation3.rs renamed to tests/mir-opt/const_prop/const_allocation3.rs

@@ -1,6 +1,6 @@
-// unit-test: DataflowConstProp
+// unit-test: ConstProp
 
-// EMIT_MIR if.main.DataflowConstProp.diff
+// EMIT_MIR if.main.ConstProp.diff
 fn main() {
     let a = 1;
     let b = if a == 1 { 2 } else { 3 };

tests/mir-opt/const_prop_miscompile.bar.ConstProp.diff renamed to tests/mir-opt/const_prop/const_prop_miscompile.bar.ConstProp.diff

@@ -17,7 +17,7 @@
 -         _3 = CheckedAdd(_2, const 1_u8);
 -         assert(!move (_3.1: bool), "attempt to compute `{} + {}`, which would overflow", move _2, const 1_u8) -> [success: bb1, unwind unreachable];
 +         _2 = const 2_u8;
-+         _3 = const (3_u8, false);
++         _3 = CheckedAdd(const 2_u8, const 1_u8);
 +         assert(!const false, "attempt to compute `{} + {}`, which would overflow", const 2_u8, const 1_u8) -> [success: bb1, unwind unreachable];
       }
 

tests/mir-opt/const_prop_miscompile.foo.ConstProp.diff renamed to tests/mir-opt/const_prop/const_prop_miscompile.foo.ConstProp.diff

@@ -17,7 +17,7 @@
 -         _3 = CheckedAdd(_2, const 1_u8);
 -         assert(!move (_3.1: bool), "attempt to compute `{} + {}`, which would overflow", move _2, const 1_u8) -> [success: bb1, unwind continue];
 +         _2 = const 2_u8;
-+         _3 = const (3_u8, false);
++         _3 = CheckedAdd(const 2_u8, const 1_u8);
 +         assert(!const false, "attempt to compute `{} + {}`, which would overflow", const 2_u8, const 1_u8) -> [success: bb1, unwind continue];
       }
 

tests/mir-opt/const_prop_miscompile.rs renamed to tests/mir-opt/const_prop/const_prop_miscompile.rs

@@ -22,7 +22,7 @@
           _3 = const 1_u8;
 -         _4 = CheckedAdd(_2, _3);
 -         assert(!move (_4.1: bool), "attempt to compute `{} + {}`, which would overflow", _2, _3) -> [success: bb1, unwind unreachable];
-+         _4 = const (0_u8, true);
++         _4 = CheckedAdd(const u8::MAX, const 1_u8);
 +         assert(!const true, "attempt to compute `{} + {}`, which would overflow", const u8::MAX, const 1_u8) -> [success: bb1, unwind unreachable];
       }