Add mir-opt tests to track MIR quality.

tests/mir-opt/pre-codegen/README.md

@@ -0,0 +1,3 @@
+The goal of this directory is to track the quality of MIR that is given to codegen in a standard `-O` condiguration.
+
+As such, feel free to `--bless` whatever changes you get here, so long as doing so doesn't add substantially more MIR.

tests/mir-opt/instcombine_duplicate_switch_targets_e2e.rs → tests/mir-opt/pre-codegen/duplicate_switch_targets.rs

@@ -1,13 +1,14 @@
-// compile-flags: -Zmir-opt-level=2 -Zinline-mir
+// compile-flags: -O -Zmir-opt-level=2 -Cdebuginfo=0
 // ignore-debug: standard library debug assertions add a panic that breaks this optimization
+
 #![crate_type = "lib"]
 
 pub enum Thing {
     A,
     B,
 }
 
-// EMIT_MIR instcombine_duplicate_switch_targets_e2e.ub_if_b.PreCodegen.after.mir
+// EMIT_MIR duplicate_switch_targets.ub_if_b.PreCodegen.after.mir
 pub unsafe fn ub_if_b(t: Thing) -> Thing {
     match t {
         Thing::A => t,

tests/mir-opt/pre-codegen/duplicate_switch_targets.ub_if_b.PreCodegen.after.mir

@@ -0,0 +1,27 @@
+// MIR for `ub_if_b` after PreCodegen
+
+fn ub_if_b(_1: Thing) -> Thing {
+    debug t => _1;                       // in scope 0 at $DIR/duplicate_switch_targets.rs:+0:23: +0:24
+    let mut _0: Thing;                   // return place in scope 0 at $DIR/duplicate_switch_targets.rs:+0:36: +0:41
+    let mut _2: isize;                   // in scope 0 at $DIR/duplicate_switch_targets.rs:+2:9: +2:17
+    scope 1 (inlined unreachable_unchecked) { // at $DIR/duplicate_switch_targets.rs:15:21: 15:55
+        scope 2 {
+            scope 3 (inlined unreachable_unchecked::runtime) { // at $SRC_DIR/core/src/intrinsics.rs:LL:COL
+            }
+        }
+    }
+
+    bb0: {
+        _2 = discriminant(_1);           // scope 0 at $DIR/duplicate_switch_targets.rs:+1:11: +1:12
+        switchInt(move _2) -> [0: bb2, otherwise: bb1]; // scope 0 at $DIR/duplicate_switch_targets.rs:+1:5: +1:12
+    }
+
+    bb1: {
+        unreachable;                     // scope 2 at $SRC_DIR/core/src/intrinsics.rs:LL:COL
+    }
+
+    bb2: {
+        _0 = move _1;                    // scope 0 at $DIR/duplicate_switch_targets.rs:+2:21: +2:22
+        return;                          // scope 0 at $DIR/duplicate_switch_targets.rs:+5:2: +5:2
+    }
+}

tests/mir-opt/pre-codegen/intrinsics.f_u64.PreCodegen.after.mir

@@ -0,0 +1,26 @@
+// MIR for `f_u64` after PreCodegen
+
+fn f_u64() -> () {
+    let mut _0: ();                      // return place in scope 0 at $DIR/intrinsics.rs:+0:16: +0:16
+    let mut _1: u64;                     // in scope 0 at $DIR/intrinsics.rs:+1:5: +1:21
+    scope 1 (inlined f_dispatch::<u64>) { // at $DIR/intrinsics.rs:19:5: 19:21
+        debug t => const 0_u64;          // in scope 1 at $DIR/intrinsics.rs:23:22: 23:23
+        let _2: ();                      // in scope 1 at $DIR/intrinsics.rs:27:9: 27:21
+        scope 2 (inlined std::mem::size_of::<u64>) { // at $DIR/intrinsics.rs:24:8: 24:32
+        }
+    }
+
+    bb0: {
+        StorageLive(_1);                 // scope 0 at $DIR/intrinsics.rs:+1:5: +1:21
+        _1 = const 0_u64;                // scope 0 at $DIR/intrinsics.rs:+1:5: +1:21
+        _2 = f_non_zst::<u64>(move _1) -> [return: bb1, unwind unreachable]; // scope 1 at $DIR/intrinsics.rs:27:9: 27:21
+                                         // mir::Constant
+                                         // + span: $DIR/intrinsics.rs:27:9: 27:18
+                                         // + literal: Const { ty: fn(u64) {f_non_zst::<u64>}, val: Value(<ZST>) }
+    }
+
+    bb1: {
+        StorageDead(_1);                 // scope 0 at $DIR/intrinsics.rs:+1:5: +1:21
+        return;                          // scope 0 at $DIR/intrinsics.rs:+2:2: +2:2
+    }
+}

tests/mir-opt/pre-codegen/intrinsics.f_unit.PreCodegen.after.mir

@@ -0,0 +1,22 @@
+// MIR for `f_unit` after PreCodegen
+
+fn f_unit() -> () {
+    let mut _0: ();                      // return place in scope 0 at $DIR/intrinsics.rs:+0:17: +0:17
+    scope 1 (inlined f_dispatch::<()>) { // at $DIR/intrinsics.rs:13:5: 13:19
+        debug t => const ();             // in scope 1 at $DIR/intrinsics.rs:23:22: 23:23
+        let _1: ();                      // in scope 1 at $DIR/intrinsics.rs:25:9: 25:17
+        scope 2 (inlined std::mem::size_of::<()>) { // at $DIR/intrinsics.rs:24:8: 24:32
+        }
+    }
+
+    bb0: {
+        _1 = f_zst::<()>(const ()) -> [return: bb1, unwind unreachable]; // scope 1 at $DIR/intrinsics.rs:25:9: 25:17
+                                         // mir::Constant
+                                         // + span: $DIR/intrinsics.rs:25:9: 25:14
+                                         // + literal: Const { ty: fn(()) {f_zst::<()>}, val: Value(<ZST>) }
+    }
+
+    bb1: {
+        return;                          // scope 0 at $DIR/intrinsics.rs:+2:2: +2:2
+    }
+}

tests/mir-opt/lower_intrinsics_e2e.rs → tests/mir-opt/pre-codegen/intrinsics.rs

@@ -1,16 +1,20 @@
+// compile-flags: -O -C debuginfo=0 -Zmir-opt-level=2
+// only-64bit
+// ignore-debug
+
 // Checks that we do not have any branches in the MIR for the two tested functions.
 
 // compile-flags: -Cpanic=abort
 #![feature(core_intrinsics)]
 #![crate_type = "lib"]
 
-// EMIT_MIR lower_intrinsics_e2e.f_unit.PreCodegen.after.mir
+// EMIT_MIR intrinsics.f_unit.PreCodegen.after.mir
 pub fn f_unit() {
     f_dispatch(());
 }
 
 
-// EMIT_MIR lower_intrinsics_e2e.f_u64.PreCodegen.after.mir
+// EMIT_MIR intrinsics.f_u64.PreCodegen.after.mir
 pub fn f_u64() {
     f_dispatch(0u64);
 }

tests/mir-opt/const_prop/optimizes_into_variable.rs → tests/mir-opt/pre-codegen/optimizes_into_variable.rs

@@ -1,5 +1,4 @@
 // ignore-wasm32 compiled with panic=abort by default
-// unit-test
 // compile-flags: -C overflow-checks=on
 
 struct Point {

tests/mir-opt/pre-codegen/range_iter.forward_loop.PreCodegen.after.mir

@@ -0,0 +1,91 @@
+// MIR for `forward_loop` after PreCodegen
+
+fn forward_loop(_1: u32, _2: u32, _3: impl Fn(u32)) -> () {
+    debug start => _1;                   // in scope 0 at $DIR/range_iter.rs:+0:21: +0:26
+    debug end => _2;                     // in scope 0 at $DIR/range_iter.rs:+0:33: +0:36
+    debug f => _3;                       // in scope 0 at $DIR/range_iter.rs:+0:43: +0:44
+    let mut _0: ();                      // return place in scope 0 at $DIR/range_iter.rs:+0:60: +0:60
+    let mut _4: std::ops::Range<u32>;    // in scope 0 at $DIR/range_iter.rs:+1:14: +1:24
+    let mut _5: std::ops::Range<u32>;    // in scope 0 at $DIR/range_iter.rs:+1:14: +1:24
+    let _6: ();                          // in scope 0 at $DIR/range_iter.rs:+1:14: +1:24
+    let mut _7: std::option::Option<u32>; // in scope 0 at $DIR/range_iter.rs:+1:14: +1:24
+    let mut _8: &mut std::ops::Range<u32>; // in scope 0 at $DIR/range_iter.rs:+1:14: +1:24
+    let mut _9: isize;                   // in scope 0 at $DIR/range_iter.rs:+1:5: +3:6
+    let mut _11: &impl Fn(u32);          // in scope 0 at $DIR/range_iter.rs:+2:9: +2:10
+    let mut _12: (u32,);                 // in scope 0 at $DIR/range_iter.rs:+2:9: +2:13
+    scope 1 {
+        debug iter => _5;                // in scope 1 at $DIR/range_iter.rs:+1:14: +1:24
+        let _10: u32;                    // in scope 1 at $DIR/range_iter.rs:+1:9: +1:10
+        scope 2 {
+            debug x => _10;              // in scope 2 at $DIR/range_iter.rs:+1:9: +1:10
+        }
+        scope 4 (inlined iter::range::<impl Iterator for std::ops::Range<u32>>::next) { // at $DIR/range_iter.rs:21:14: 21:24
+            debug self => _8;            // in scope 4 at $SRC_DIR/core/src/iter/range.rs:LL:COL
+        }
+    }
+    scope 3 (inlined <std::ops::Range<u32> as IntoIterator>::into_iter) { // at $DIR/range_iter.rs:21:14: 21:24
+        debug self => _4;                // in scope 3 at $SRC_DIR/core/src/iter/traits/collect.rs:LL:COL
+    }
+
+    bb0: {
+        _4 = std::ops::Range::<u32> { start: _1, end: _2 }; // scope 0 at $DIR/range_iter.rs:+1:14: +1:24
+        StorageLive(_5);                 // scope 0 at $DIR/range_iter.rs:+1:14: +1:24
+        _5 = move _4;                    // scope 0 at $DIR/range_iter.rs:+1:14: +1:24
+        goto -> bb1;                     // scope 1 at $DIR/range_iter.rs:+1:5: +3:6
+    }
+
+    bb1: {
+        StorageLive(_7);                 // scope 1 at $DIR/range_iter.rs:+1:14: +1:24
+        _8 = &mut _5;                    // scope 1 at $DIR/range_iter.rs:+1:14: +1:24
+        _7 = <std::ops::Range<u32> as iter::range::RangeIteratorImpl>::spec_next(_8) -> [return: bb9, unwind: bb7]; // scope 4 at $SRC_DIR/core/src/iter/range.rs:LL:COL
+                                         // mir::Constant
+                                         // + span: $SRC_DIR/core/src/iter/range.rs:LL:COL
+                                         // + literal: Const { ty: for<'a> fn(&'a mut std::ops::Range<u32>) -> Option<<std::ops::Range<u32> as iter::range::RangeIteratorImpl>::Item> {<std::ops::Range<u32> as iter::range::RangeIteratorImpl>::spec_next}, val: Value(<ZST>) }
+    }
+
+    bb2: {
+        _10 = ((_7 as Some).0: u32);     // scope 1 at $DIR/range_iter.rs:+1:9: +1:10
+        StorageLive(_11);                // scope 2 at $DIR/range_iter.rs:+2:9: +2:10
+        _11 = &_3;                       // scope 2 at $DIR/range_iter.rs:+2:9: +2:10
+        StorageLive(_12);                // scope 2 at $DIR/range_iter.rs:+2:9: +2:13
+        _12 = (_10,);                    // scope 2 at $DIR/range_iter.rs:+2:9: +2:13
+        _6 = <impl Fn(u32) as Fn<(u32,)>>::call(move _11, move _12) -> [return: bb5, unwind: bb7]; // scope 2 at $DIR/range_iter.rs:+2:9: +2:13
+                                         // mir::Constant
+                                         // + span: $DIR/range_iter.rs:22:9: 22:10
+                                         // + literal: Const { ty: for<'a> extern "rust-call" fn(&'a impl Fn(u32), (u32,)) -> <impl Fn(u32) as FnOnce<(u32,)>>::Output {<impl Fn(u32) as Fn<(u32,)>>::call}, val: Value(<ZST>) }
+    }
+
+    bb3: {
+        unreachable;                     // scope 1 at $DIR/range_iter.rs:+1:14: +1:24
+    }
+
+    bb4: {
+        StorageDead(_7);                 // scope 1 at $DIR/range_iter.rs:+3:5: +3:6
+        StorageDead(_5);                 // scope 0 at $DIR/range_iter.rs:+3:5: +3:6
+        drop(_3) -> bb6;                 // scope 0 at $DIR/range_iter.rs:+4:1: +4:2
+    }
+
+    bb5: {
+        StorageDead(_12);                // scope 2 at $DIR/range_iter.rs:+2:12: +2:13
+        StorageDead(_11);                // scope 2 at $DIR/range_iter.rs:+2:12: +2:13
+        StorageDead(_7);                 // scope 1 at $DIR/range_iter.rs:+3:5: +3:6
+        goto -> bb1;                     // scope 1 at $DIR/range_iter.rs:+1:5: +3:6
+    }
+
+    bb6: {
+        return;                          // scope 0 at $DIR/range_iter.rs:+4:2: +4:2
+    }
+
+    bb7 (cleanup): {
+        drop(_3) -> [return: bb8, unwind terminate]; // scope 0 at $DIR/range_iter.rs:+4:1: +4:2
+    }
+
+    bb8 (cleanup): {
+        resume;                          // scope 0 at $DIR/range_iter.rs:+0:1: +4:2
+    }
+
+    bb9: {
+        _9 = discriminant(_7);           // scope 1 at $DIR/range_iter.rs:+1:14: +1:24
+        switchInt(move _9) -> [0: bb4, 1: bb2, otherwise: bb3]; // scope 1 at $DIR/range_iter.rs:+1:14: +1:24
+    }
+}

tests/mir-opt/pre-codegen/range_iter.inclusive_loop.PreCodegen.after.mir

@@ -0,0 +1,95 @@
+// MIR for `inclusive_loop` after PreCodegen
+
+fn inclusive_loop(_1: u32, _2: u32, _3: impl Fn(u32)) -> () {
+    debug start => _1;                   // in scope 0 at $DIR/range_iter.rs:+0:23: +0:28
+    debug end => _2;                     // in scope 0 at $DIR/range_iter.rs:+0:35: +0:38
+    debug f => _3;                       // in scope 0 at $DIR/range_iter.rs:+0:45: +0:46
+    let mut _0: ();                      // return place in scope 0 at $DIR/range_iter.rs:+0:62: +0:62
+    let mut _4: std::ops::RangeInclusive<u32>; // in scope 0 at $DIR/range_iter.rs:+1:14: +1:25
+    let mut _5: std::ops::RangeInclusive<u32>; // in scope 0 at $DIR/range_iter.rs:+1:14: +1:25
+    let _6: ();                          // in scope 0 at $DIR/range_iter.rs:+1:14: +1:25
+    let mut _7: std::option::Option<u32>; // in scope 0 at $DIR/range_iter.rs:+1:14: +1:25
+    let mut _8: &mut std::ops::RangeInclusive<u32>; // in scope 0 at $DIR/range_iter.rs:+1:14: +1:25
+    let mut _9: isize;                   // in scope 0 at $DIR/range_iter.rs:+1:5: +3:6
+    let mut _11: &impl Fn(u32);          // in scope 0 at $DIR/range_iter.rs:+2:9: +2:10
+    let mut _12: (u32,);                 // in scope 0 at $DIR/range_iter.rs:+2:9: +2:13
+    scope 1 {
+        debug iter => _5;                // in scope 1 at $DIR/range_iter.rs:+1:14: +1:25
+        let _10: u32;                    // in scope 1 at $DIR/range_iter.rs:+1:9: +1:10
+        scope 2 {
+            debug x => _10;              // in scope 2 at $DIR/range_iter.rs:+1:9: +1:10
+        }
+        scope 5 (inlined iter::range::<impl Iterator for RangeInclusive<u32>>::next) { // at $DIR/range_iter.rs:28:14: 28:25
+            debug self => _8;            // in scope 5 at $SRC_DIR/core/src/iter/range.rs:LL:COL
+        }
+    }
+    scope 3 (inlined RangeInclusive::<u32>::new) { // at $DIR/range_iter.rs:28:14: 28:25
+        debug start => _1;               // in scope 3 at $SRC_DIR/core/src/ops/range.rs:LL:COL
+        debug end => _2;                 // in scope 3 at $SRC_DIR/core/src/ops/range.rs:LL:COL
+    }
+    scope 4 (inlined <RangeInclusive<u32> as IntoIterator>::into_iter) { // at $DIR/range_iter.rs:28:14: 28:25
+        debug self => _4;                // in scope 4 at $SRC_DIR/core/src/iter/traits/collect.rs:LL:COL
+    }
+
+    bb0: {
+        _4 = RangeInclusive::<u32> { start: _1, end: _2, exhausted: const false }; // scope 3 at $SRC_DIR/core/src/ops/range.rs:LL:COL
+        StorageLive(_5);                 // scope 0 at $DIR/range_iter.rs:+1:14: +1:25
+        _5 = move _4;                    // scope 0 at $DIR/range_iter.rs:+1:14: +1:25
+        goto -> bb1;                     // scope 1 at $DIR/range_iter.rs:+1:5: +3:6
+    }
+
+    bb1: {
+        StorageLive(_7);                 // scope 1 at $DIR/range_iter.rs:+1:14: +1:25
+        _8 = &mut _5;                    // scope 1 at $DIR/range_iter.rs:+1:14: +1:25
+        _7 = <RangeInclusive<u32> as iter::range::RangeInclusiveIteratorImpl>::spec_next(_8) -> [return: bb9, unwind: bb7]; // scope 5 at $SRC_DIR/core/src/iter/range.rs:LL:COL
+                                         // mir::Constant
+                                         // + span: $SRC_DIR/core/src/iter/range.rs:LL:COL
+                                         // + literal: Const { ty: for<'a> fn(&'a mut RangeInclusive<u32>) -> Option<<RangeInclusive<u32> as iter::range::RangeInclusiveIteratorImpl>::Item> {<RangeInclusive<u32> as iter::range::RangeInclusiveIteratorImpl>::spec_next}, val: Value(<ZST>) }
+    }
+
+    bb2: {
+        _10 = ((_7 as Some).0: u32);     // scope 1 at $DIR/range_iter.rs:+1:9: +1:10
+        StorageLive(_11);                // scope 2 at $DIR/range_iter.rs:+2:9: +2:10
+        _11 = &_3;                       // scope 2 at $DIR/range_iter.rs:+2:9: +2:10
+        StorageLive(_12);                // scope 2 at $DIR/range_iter.rs:+2:9: +2:13
+        _12 = (_10,);                    // scope 2 at $DIR/range_iter.rs:+2:9: +2:13
+        _6 = <impl Fn(u32) as Fn<(u32,)>>::call(move _11, move _12) -> [return: bb5, unwind: bb7]; // scope 2 at $DIR/range_iter.rs:+2:9: +2:13
+                                         // mir::Constant
+                                         // + span: $DIR/range_iter.rs:29:9: 29:10
+                                         // + literal: Const { ty: for<'a> extern "rust-call" fn(&'a impl Fn(u32), (u32,)) -> <impl Fn(u32) as FnOnce<(u32,)>>::Output {<impl Fn(u32) as Fn<(u32,)>>::call}, val: Value(<ZST>) }
+    }
+
+    bb3: {
+        unreachable;                     // scope 1 at $DIR/range_iter.rs:+1:14: +1:25
+    }
+
+    bb4: {
+        StorageDead(_7);                 // scope 1 at $DIR/range_iter.rs:+3:5: +3:6
+        StorageDead(_5);                 // scope 0 at $DIR/range_iter.rs:+3:5: +3:6
+        drop(_3) -> bb6;                 // scope 0 at $DIR/range_iter.rs:+4:1: +4:2
+    }
+
+    bb5: {
+        StorageDead(_12);                // scope 2 at $DIR/range_iter.rs:+2:12: +2:13
+        StorageDead(_11);                // scope 2 at $DIR/range_iter.rs:+2:12: +2:13
+        StorageDead(_7);                 // scope 1 at $DIR/range_iter.rs:+3:5: +3:6
+        goto -> bb1;                     // scope 1 at $DIR/range_iter.rs:+1:5: +3:6
+    }
+
+    bb6: {
+        return;                          // scope 0 at $DIR/range_iter.rs:+4:2: +4:2
+    }
+
+    bb7 (cleanup): {
+        drop(_3) -> [return: bb8, unwind terminate]; // scope 0 at $DIR/range_iter.rs:+4:1: +4:2
+    }
+
+    bb8 (cleanup): {
+        resume;                          // scope 0 at $DIR/range_iter.rs:+0:1: +4:2
+    }
+
+    bb9: {
+        _9 = discriminant(_7);           // scope 1 at $DIR/range_iter.rs:+1:14: +1:25
+        switchInt(move _9) -> [0: bb4, 1: bb2, otherwise: bb3]; // scope 1 at $DIR/range_iter.rs:+1:14: +1:25
+    }
+}