Auto merge of #36752 - jonas-schievink:vartmparg, r=eddyb

Move MIR towards a single kind of local

This PR modifies MIR to handle function arguments (`Arg`), user-defined variable bindings (`Var`), compiler-generated temporaries (`Tmp`), as well as the return value pointer equally. All of them are replaced with a single `Local` type, a few functions for iterating over different kinds of locals, and a way to get the kind of local we're dealing with (mainly used in the constant qualification/propagation passes).

~~I haven't managed to fix one remaining issue: A `StorageDead` not getting emitted for a variable (see the `TODO` in the test). If that's fixed, this is basically good to go.~~ Found the issue (an off-by-one error), fix incoming.

r? @eddyb for changes to constant qualification and propagation I'm not quite sure about

5 files changed, 47 insertions, 47 deletions

diff --git a/src/test/codegen/lifetime_start_end.rs b/src/test/codegen/lifetime_start_end.rs
index cf91e7a8bcb..81f6cf309da 100644
--- a/src/test/codegen/lifetime_start_end.rs
+++ b/src/test/codegen/lifetime_start_end.rs
@@ -30,11 +30,11 @@ pub fn test() {
 // CHECK: [[S_b:%[0-9]+]] = bitcast %"2.std::option::Option<i32>"** %b to i8*
 // CHECK: call void @llvm.lifetime.start(i{{[0-9 ]+}}, i8* [[S_b]])
 
-// CHECK: [[S_tmp2:%[0-9]+]] = bitcast %"2.std::option::Option<i32>"* %tmp2 to i8*
-// CHECK: call void @llvm.lifetime.start(i{{[0-9 ]+}}, i8* [[S_tmp2]])
+// CHECK: [[S__5:%[0-9]+]] = bitcast %"2.std::option::Option<i32>"* %_5 to i8*
+// CHECK: call void @llvm.lifetime.start(i{{[0-9 ]+}}, i8* [[S__5]])
 
-// CHECK: [[E_tmp2:%[0-9]+]] = bitcast %"2.std::option::Option<i32>"* %tmp2 to i8*
-// CHECK: call void @llvm.lifetime.end(i{{[0-9 ]+}}, i8* [[E_tmp2]])
+// CHECK: [[E__5:%[0-9]+]] = bitcast %"2.std::option::Option<i32>"* %_5 to i8*
+// CHECK: call void @llvm.lifetime.end(i{{[0-9 ]+}}, i8* [[E__5]])
 
 // CHECK: [[E_b:%[0-9]+]] = bitcast %"2.std::option::Option<i32>"** %b to i8*
 // CHECK: call void @llvm.lifetime.end(i{{[0-9 ]+}}, i8* [[E_b]])
diff --git a/src/test/mir-opt/deaggregator_test.rs b/src/test/mir-opt/deaggregator_test.rs
index e57a9674cf6..3304a66773a 100644
--- a/src/test/mir-opt/deaggregator_test.rs
+++ b/src/test/mir-opt/deaggregator_test.rs
@@ -23,19 +23,19 @@ fn main() {}
 // END RUST SOURCE
 // START rustc.node13.Deaggregator.before.mir
 // bb0: {
-//     var0 = arg0;                     // scope 0 at main.rs:8:8: 8:9
-//     tmp0 = var0;                     // scope 1 at main.rs:9:14: 9:15
-//     return = Baz { x: tmp0, y: const F32(0), z: const false }; // scope ...
-//     goto -> bb1;                     // scope 1 at main.rs:8:1: 10:2
+//     _2 = _1;
+//     _3 = _2;
+//     _0 = Baz { x: _3, y: const F32(0), z: const false };
+//     goto -> bb1;
 // }
 // END rustc.node13.Deaggregator.before.mir
 // START rustc.node13.Deaggregator.after.mir
 // bb0: {
-//     var0 = arg0;                     // scope 0 at main.rs:8:8: 8:9
-//     tmp0 = var0;                     // scope 1 at main.rs:9:14: 9:15
-//     (return.0: usize) = tmp0;        // scope 1 at main.rs:9:5: 9:34
-//     (return.1: f32) = const F32(0);  // scope 1 at main.rs:9:5: 9:34
-//     (return.2: bool) = const false;  // scope 1 at main.rs:9:5: 9:34
-//     goto -> bb1;                     // scope 1 at main.rs:8:1: 10:2
+//     _2 = _1;
+//     _3 = _2;
+//     (_0.0: usize) = _3;
+//     (_0.1: f32) = const F32(0);
+//     (_0.2: bool) = const false;
+//     goto -> bb1;
 // }
-// END rustc.node13.Deaggregator.after.mir
\ No newline at end of file
+// END rustc.node13.Deaggregator.after.mir
diff --git a/src/test/mir-opt/deaggregator_test_enum.rs b/src/test/mir-opt/deaggregator_test_enum.rs
index ccfa760a28c..a6f12886f55 100644
--- a/src/test/mir-opt/deaggregator_test_enum.rs
+++ b/src/test/mir-opt/deaggregator_test_enum.rs
@@ -28,18 +28,18 @@ fn main() {
 // END RUST SOURCE
 // START rustc.node10.Deaggregator.before.mir
 // bb0: {
-//     var0 = arg0;                     // scope 0 at main.rs:7:8: 7:9
-//     tmp0 = var0;                     // scope 1 at main.rs:8:19: 8:20
-//     return = Baz::Foo { x: tmp0 };   // scope 1 at main.rs:8:5: 8:21
-//     goto -> bb1;                     // scope 1 at main.rs:7:1: 9:2
+//     _2 = _1;
+//     _3 = _2;
+//     _0 = Baz::Foo { x: _3 };
+//     goto -> bb1;
 // }
 // END rustc.node10.Deaggregator.before.mir
 // START rustc.node10.Deaggregator.after.mir
 // bb0: {
-//     var0 = arg0;                     // scope 0 at main.rs:7:8: 7:9
-//     tmp0 = var0;                     // scope 1 at main.rs:8:19: 8:20
-//     ((return as Foo).0: usize) = tmp0; // scope 1 at main.rs:8:5: 8:21
-//     discriminant(return) = 1;         // scope 1 at main.rs:8:5: 8:21
-//     goto -> bb1;                     // scope 1 at main.rs:7:1: 9:2
+//     _2 = _1;
+//     _3 = _2;
+//     ((_0 as Foo).0: usize) = _3;
+//     discriminant(_0) = 1;
+//     goto -> bb1;
 // }
-// END rustc.node10.Deaggregator.after.mir
\ No newline at end of file
+// END rustc.node10.Deaggregator.after.mir
diff --git a/src/test/mir-opt/simplify_if.rs b/src/test/mir-opt/simplify_if.rs
index dd6a8579604..7239e32357b 100644
--- a/src/test/mir-opt/simplify_if.rs
+++ b/src/test/mir-opt/simplify_if.rs
@@ -17,11 +17,11 @@ fn main() {
 // END RUST SOURCE
 // START rustc.node4.SimplifyBranches.initial-before.mir
 // bb0: {
-//     if(const false) -> [true: bb1, false: bb2]; // scope 0 at simplify_if.rs:12:5: 14:6
+//     if(const false) -> [true: bb1, false: bb2];
 // }
 // END rustc.node4.SimplifyBranches.initial-before.mir
 // START rustc.node4.SimplifyBranches.initial-after.mir
 // bb0: {
-//     goto -> bb2;                     // scope 0 at simplify_if.rs:12:5: 14:6
+//     goto -> bb2;
 // }
-// END rustc.node4.SimplifyBranches.initial-after.mir
\ No newline at end of file
+// END rustc.node4.SimplifyBranches.initial-after.mir
diff --git a/src/test/mir-opt/storage_ranges.rs b/src/test/mir-opt/storage_ranges.rs
index 4ed0c8bc9ff..3885b233fd2 100644
--- a/src/test/mir-opt/storage_ranges.rs
+++ b/src/test/mir-opt/storage_ranges.rs
@@ -21,27 +21,27 @@ fn main() {
 // END RUST SOURCE
 // START rustc.node4.TypeckMir.before.mir
 //     bb0: {
-//         StorageLive(var0);               // scope 0 at storage_ranges.rs:14:9: 14:10
-//         var0 = const 0i32;               // scope 0 at storage_ranges.rs:14:13: 14:14
-//         StorageLive(var1);               // scope 1 at storage_ranges.rs:16:13: 16:14
-//         StorageLive(tmp1);               // scope 1 at storage_ranges.rs:16:18: 16:25
-//         StorageLive(tmp2);               // scope 1 at storage_ranges.rs:16:23: 16:24
-//         tmp2 = var0;                     // scope 1 at storage_ranges.rs:16:23: 16:24
-//         tmp1 = std::option::Option<i32>::Some(tmp2,); // scope 1 at storage_ranges.rs:16:18: 16:25
-//         var1 = &tmp1;                    // scope 1 at storage_ranges.rs:16:17: 16:25
-//         StorageDead(tmp2);               // scope 1 at storage_ranges.rs:16:23: 16:24
-//         tmp0 = ();                       // scope 2 at storage_ranges.rs:15:5: 17:6
-//         StorageDead(tmp1);               // scope 1 at storage_ranges.rs:16:18: 16:25
-//         StorageDead(var1);               // scope 1 at storage_ranges.rs:16:13: 16:14
-//         StorageLive(var2);               // scope 1 at storage_ranges.rs:18:9: 18:10
-//         var2 = const 1i32;               // scope 1 at storage_ranges.rs:18:13: 18:14
-//         return = ();                     // scope 3 at storage_ranges.rs:13:11: 19:2
-//         StorageDead(var2);               // scope 1 at storage_ranges.rs:18:9: 18:10
-//         StorageDead(var0);               // scope 0 at storage_ranges.rs:14:9: 14:10
-//         goto -> bb1;                     // scope 0 at storage_ranges.rs:13:1: 19:2
+//         StorageLive(_1);
+//         _1 = const 0i32;
+//         StorageLive(_3);
+//         StorageLive(_4);
+//         StorageLive(_5);
+//         _5 = _1;
+//         _4 = std::option::Option<i32>::Some(_5,);
+//         _3 = &_4;
+//         StorageDead(_5);
+//         _2 = ();
+//         StorageDead(_4);
+//         StorageDead(_3);
+//         StorageLive(_6);
+//         _6 = const 1i32;
+//         _0 = ();
+//         StorageDead(_6);
+//         StorageDead(_1);
+//         goto -> bb1;
 //     }
 //
 //     bb1: {
-//         return;                          // scope 0 at storage_ranges.rs:13:1: 19:2
+//         return;
 //     }
 // END rustc.node4.TypeckMir.before.mir