simplify_cfg: rename some passes so that they make more sense

compiler/rustc_mir_transform/src/lib.rs

@@ -507,7 +507,7 @@ fn run_analysis_cleanup_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
     let passes: &[&dyn MirPass<'tcx>] = &[
         &cleanup_post_borrowck::CleanupPostBorrowck,
         &remove_noop_landing_pads::RemoveNoopLandingPads,
-        &simplify::SimplifyCfg::EarlyOpt,
+        &simplify::SimplifyCfg::PostAnalysis,
         &deref_separator::Derefer,
     ];
 
@@ -544,7 +544,7 @@ fn run_runtime_cleanup_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
     let passes: &[&dyn MirPass<'tcx>] = &[
         &lower_intrinsics::LowerIntrinsics,
         &remove_place_mention::RemovePlaceMention,
-        &simplify::SimplifyCfg::ElaborateDrops,
+        &simplify::SimplifyCfg::PreOptimizations,
     ];
 
     pm::run_passes(tcx, body, passes, Some(MirPhase::Runtime(RuntimePhase::PostCleanup)));

compiler/rustc_mir_transform/src/simplify.rs

@@ -37,8 +37,11 @@ pub enum SimplifyCfg {
     Initial,
     PromoteConsts,
     RemoveFalseEdges,
-    EarlyOpt,
+    /// Runs at the beginning of "analysis to runtime" lowering, *before* drop elaboration.
-    ElaborateDrops,
+    PostAnalysis,
+    /// Runs at the end of "analysis to runtime" lowering, *after* drop elaboration.
+    /// This is before the main optimization passes on runtime MIR kick in.
+    PreOptimizations,
     Final,
     MakeShim,
     AfterUninhabitedEnumBranching,
@@ -50,8 +53,8 @@ pub fn name(&self) -> &'static str {
             SimplifyCfg::Initial => "SimplifyCfg-initial",
             SimplifyCfg::PromoteConsts => "SimplifyCfg-promote-consts",
             SimplifyCfg::RemoveFalseEdges => "SimplifyCfg-remove-false-edges",
-            SimplifyCfg::EarlyOpt => "SimplifyCfg-early-opt",
+            SimplifyCfg::PostAnalysis => "SimplifyCfg-post-analysis",
-            SimplifyCfg::ElaborateDrops => "SimplifyCfg-elaborate-drops",
+            SimplifyCfg::PreOptimizations => "SimplifyCfg-pre-optimizations",
             SimplifyCfg::Final => "SimplifyCfg-final",
             SimplifyCfg::MakeShim => "SimplifyCfg-make_shim",
             SimplifyCfg::AfterUninhabitedEnumBranching => {

tests/mir-opt/array_index_is_temporary.main.SimplifyCfg-pre-optimizations.after.panic-abort.mir

@@ -1,4 +1,4 @@
-// MIR for `main` after SimplifyCfg-elaborate-drops
+// MIR for `main` after SimplifyCfg-pre-optimizations
 
 fn main() -> () {
     let mut _0: ();

tests/mir-opt/array_index_is_temporary.main.SimplifyCfg-pre-optimizations.after.panic-unwind.mir

@@ -1,4 +1,4 @@
-// MIR for `main` after SimplifyCfg-elaborate-drops
+// MIR for `main` after SimplifyCfg-pre-optimizations
 
 fn main() -> () {
     let mut _0: ();

tests/mir-opt/array_index_is_temporary.rs

@@ -1,4 +1,4 @@
-//@ unit-test: SimplifyCfg-elaborate-drops
+//@ unit-test: SimplifyCfg-pre-optimizations
 // EMIT_MIR_FOR_EACH_PANIC_STRATEGY
 // Retagging (from Stacked Borrows) relies on the array index being a fresh
 // temporary, so that side-effects cannot change it.
@@ -10,7 +10,7 @@ unsafe fn foo(z: *mut usize) -> u32 {
 }
 
 
-// EMIT_MIR array_index_is_temporary.main.SimplifyCfg-elaborate-drops.after.mir
+// EMIT_MIR array_index_is_temporary.main.SimplifyCfg-pre-optimizations.after.mir
 fn main() {
     // CHECK-LABEL: fn main(
     // CHECK: debug x => [[x:_.*]];

tests/mir-opt/byte_slice.main.SimplifyCfg-pre-optimizations.after.mir

@@ -1,4 +1,4 @@
-// MIR for `main` after SimplifyCfg-elaborate-drops
+// MIR for `main` after SimplifyCfg-pre-optimizations
 
 fn main() -> () {
     let mut _0: ();

tests/mir-opt/byte_slice.rs

@@ -1,7 +1,7 @@
 // skip-filecheck
 //@ compile-flags: -Z mir-opt-level=0
 
-// EMIT_MIR byte_slice.main.SimplifyCfg-elaborate-drops.after.mir
+// EMIT_MIR byte_slice.main.SimplifyCfg-pre-optimizations.after.mir
 fn main() {
     let x = b"foo";
     let y = [5u8, b'x'];

tests/mir-opt/const_promotion_extern_static.BAR-promoted[0].SimplifyCfg-pre-optimizations.after.mir

@@ -1,4 +1,4 @@
-// MIR for `BAR::promoted[0]` after SimplifyCfg-elaborate-drops
+// MIR for `BAR::promoted[0]` after SimplifyCfg-pre-optimizations
 
 const BAR::promoted[0]: &[&i32; 1] = {
     let mut _0: &[&i32; 1];

tests/mir-opt/const_promotion_extern_static.FOO-promoted[0].SimplifyCfg-pre-optimizations.after.mir

@@ -1,4 +1,4 @@
-// MIR for `FOO::promoted[0]` after SimplifyCfg-elaborate-drops
+// MIR for `FOO::promoted[0]` after SimplifyCfg-pre-optimizations
 
 const FOO::promoted[0]: &[&i32; 1] = {
     let mut _0: &[&i32; 1];

tests/mir-opt/const_promotion_extern_static.rs

@@ -6,11 +6,11 @@
 static Y: i32 = 42;
 
 // EMIT_MIR const_promotion_extern_static.BAR.PromoteTemps.diff
-// EMIT_MIR const_promotion_extern_static.BAR-promoted[0].SimplifyCfg-elaborate-drops.after.mir
+// EMIT_MIR const_promotion_extern_static.BAR-promoted[0].SimplifyCfg-pre-optimizations.after.mir
 static mut BAR: *const &i32 = [&Y].as_ptr();
 
 // EMIT_MIR const_promotion_extern_static.FOO.PromoteTemps.diff
-// EMIT_MIR const_promotion_extern_static.FOO-promoted[0].SimplifyCfg-elaborate-drops.after.mir
+// EMIT_MIR const_promotion_extern_static.FOO-promoted[0].SimplifyCfg-pre-optimizations.after.mir
 static mut FOO: *const &i32 = [unsafe { &X }].as_ptr();
 
 // EMIT_MIR const_promotion_extern_static.BOP.built.after.mir

tests/mir-opt/no_drop_for_inactive_variant.rs

@@ -4,7 +4,7 @@
 // Ensure that there are no drop terminators in `unwrap<T>` (except the one along the cleanup
 // path).
 
-// EMIT_MIR no_drop_for_inactive_variant.unwrap.SimplifyCfg-elaborate-drops.after.mir
+// EMIT_MIR no_drop_for_inactive_variant.unwrap.SimplifyCfg-pre-optimizations.after.mir
 fn unwrap<T>(opt: Option<T>) -> T {
     match opt {
         Some(x) => x,

tests/mir-opt/no_drop_for_inactive_variant.unwrap.SimplifyCfg-pre-optimizations.after.panic-abort.mir

@@ -1,4 +1,4 @@
-// MIR for `unwrap` after SimplifyCfg-elaborate-drops
+// MIR for `unwrap` after SimplifyCfg-pre-optimizations
 
 fn unwrap(_1: Option<T>) -> T {
     debug opt => _1;

tests/mir-opt/no_drop_for_inactive_variant.unwrap.SimplifyCfg-pre-optimizations.after.panic-unwind.mir

@@ -1,4 +1,4 @@
-// MIR for `unwrap` after SimplifyCfg-elaborate-drops
+// MIR for `unwrap` after SimplifyCfg-pre-optimizations
 
 fn unwrap(_1: Option<T>) -> T {
     debug opt => _1;

tests/mir-opt/packed_struct_drop_aligned.main.SimplifyCfg-pre-optimizations.after.panic-abort.mir

@@ -1,4 +1,4 @@
-// MIR for `main` after SimplifyCfg-elaborate-drops
+// MIR for `main` after SimplifyCfg-pre-optimizations
 
 fn main() -> () {
     let mut _0: ();

tests/mir-opt/packed_struct_drop_aligned.main.SimplifyCfg-pre-optimizations.after.panic-unwind.mir

@@ -1,4 +1,4 @@
-// MIR for `main` after SimplifyCfg-elaborate-drops
+// MIR for `main` after SimplifyCfg-pre-optimizations
 
 fn main() -> () {
     let mut _0: ();

tests/mir-opt/packed_struct_drop_aligned.rs

@@ -2,7 +2,7 @@
 // EMIT_MIR_FOR_EACH_PANIC_STRATEGY
 
 
-// EMIT_MIR packed_struct_drop_aligned.main.SimplifyCfg-elaborate-drops.after.mir
+// EMIT_MIR packed_struct_drop_aligned.main.SimplifyCfg-pre-optimizations.after.mir
 fn main() {
     let mut x = Packed(Aligned(Droppy(0)));
     x.0 = Aligned(Droppy(0));

tests/mir-opt/retag.array_casts.SimplifyCfg-pre-optimizations.after.panic-abort.mir

@@ -1,4 +1,4 @@
-// MIR for `array_casts` after SimplifyCfg-elaborate-drops
+// MIR for `array_casts` after SimplifyCfg-pre-optimizations
 
 fn array_casts() -> () {
     let mut _0: ();

tests/mir-opt/retag.array_casts.SimplifyCfg-pre-optimizations.after.panic-unwind.mir

@@ -1,4 +1,4 @@
-// MIR for `array_casts` after SimplifyCfg-elaborate-drops
+// MIR for `array_casts` after SimplifyCfg-pre-optimizations
 
 fn array_casts() -> () {
     let mut _0: ();

tests/mir-opt/retag.main-{closure#0}.SimplifyCfg-pre-optimizations.after.panic-abort.mir

@@ -1,4 +1,4 @@
-// MIR for `main::{closure#0}` after SimplifyCfg-elaborate-drops
+// MIR for `main::{closure#0}` after SimplifyCfg-pre-optimizations
 
 fn main::{closure#0}(_1: &{closure@main::{closure#0}}, _2: &i32) -> &i32 {
     debug x => _2;

tests/mir-opt/retag.main-{closure#0}.SimplifyCfg-pre-optimizations.after.panic-unwind.mir

@@ -1,4 +1,4 @@
-// MIR for `main::{closure#0}` after SimplifyCfg-elaborate-drops
+// MIR for `main::{closure#0}` after SimplifyCfg-pre-optimizations
 
 fn main::{closure#0}(_1: &{closure@main::{closure#0}}, _2: &i32) -> &i32 {
     debug x => _2;

tests/mir-opt/retag.main.SimplifyCfg-pre-optimizations.after.panic-abort.mir

@@ -1,4 +1,4 @@
-// MIR for `main` after SimplifyCfg-elaborate-drops
+// MIR for `main` after SimplifyCfg-pre-optimizations
 
 fn main() -> () {
     let mut _0: ();

tests/mir-opt/retag.main.SimplifyCfg-pre-optimizations.after.panic-unwind.mir

@@ -1,4 +1,4 @@
-// MIR for `main` after SimplifyCfg-elaborate-drops
+// MIR for `main` after SimplifyCfg-pre-optimizations
 
 fn main() -> () {
     let mut _0: ();

tests/mir-opt/retag.rs

@@ -8,8 +8,8 @@
 
 struct Test(i32);
 
-// EMIT_MIR retag.{impl#0}-foo.SimplifyCfg-elaborate-drops.after.mir
+// EMIT_MIR retag.{impl#0}-foo.SimplifyCfg-pre-optimizations.after.mir
-// EMIT_MIR retag.{impl#0}-foo_shr.SimplifyCfg-elaborate-drops.after.mir
+// EMIT_MIR retag.{impl#0}-foo_shr.SimplifyCfg-pre-optimizations.after.mir
 impl Test {
     // Make sure we run the pass on a method, not just on bare functions.
     fn foo<'x>(&self, x: &'x mut i32) -> &'x mut i32 {
@@ -26,8 +26,8 @@ impl Drop for Test {
     fn drop(&mut self) {}
 }
 
-// EMIT_MIR retag.main.SimplifyCfg-elaborate-drops.after.mir
+// EMIT_MIR retag.main.SimplifyCfg-pre-optimizations.after.mir
-// EMIT_MIR retag.main-{closure#0}.SimplifyCfg-elaborate-drops.after.mir
+// EMIT_MIR retag.main-{closure#0}.SimplifyCfg-pre-optimizations.after.mir
 pub fn main() {
     let mut x = 0;
     {
@@ -55,7 +55,7 @@ pub fn main() {
 }
 
 /// Casting directly to an array should also go through `&raw` and thus add appropriate retags.
-// EMIT_MIR retag.array_casts.SimplifyCfg-elaborate-drops.after.mir
+// EMIT_MIR retag.array_casts.SimplifyCfg-pre-optimizations.after.mir
 fn array_casts() {
     let mut x: [usize; 2] = [0, 0];
     let p = &mut x as *mut usize;

tests/mir-opt/retag.{impl#0}-foo.SimplifyCfg-pre-optimizations.after.panic-abort.mir

@@ -1,4 +1,4 @@
-// MIR for `<impl at $DIR/retag.rs:13:1: 13:10>::foo` after SimplifyCfg-elaborate-drops
+// MIR for `<impl at $DIR/retag.rs:13:1: 13:10>::foo` after SimplifyCfg-pre-optimizations
 
 fn <impl at $DIR/retag.rs:13:1: 13:10>::foo(_1: &Test, _2: &mut i32) -> &mut i32 {
     debug self => _1;

tests/mir-opt/retag.{impl#0}-foo.SimplifyCfg-pre-optimizations.after.panic-unwind.mir

@@ -1,4 +1,4 @@
-// MIR for `<impl at $DIR/retag.rs:13:1: 13:10>::foo` after SimplifyCfg-elaborate-drops
+// MIR for `<impl at $DIR/retag.rs:13:1: 13:10>::foo` after SimplifyCfg-pre-optimizations
 
 fn <impl at $DIR/retag.rs:13:1: 13:10>::foo(_1: &Test, _2: &mut i32) -> &mut i32 {
     debug self => _1;

tests/mir-opt/retag.{impl#0}-foo_shr.SimplifyCfg-pre-optimizations.after.panic-abort.mir

@@ -1,4 +1,4 @@
-// MIR for `<impl at $DIR/retag.rs:13:1: 13:10>::foo_shr` after SimplifyCfg-elaborate-drops
+// MIR for `<impl at $DIR/retag.rs:13:1: 13:10>::foo_shr` after SimplifyCfg-pre-optimizations
 
 fn <impl at $DIR/retag.rs:13:1: 13:10>::foo_shr(_1: &Test, _2: &i32) -> &i32 {
     debug self => _1;

tests/mir-opt/retag.{impl#0}-foo_shr.SimplifyCfg-pre-optimizations.after.panic-unwind.mir

@@ -1,4 +1,4 @@
-// MIR for `<impl at $DIR/retag.rs:13:1: 13:10>::foo_shr` after SimplifyCfg-elaborate-drops
+// MIR for `<impl at $DIR/retag.rs:13:1: 13:10>::foo_shr` after SimplifyCfg-pre-optimizations
 
 fn <impl at $DIR/retag.rs:13:1: 13:10>::foo_shr(_1: &Test, _2: &i32) -> &i32 {
     debug self => _1;

tests/mir-opt/simplify_cfg.main.SimplifyCfg-post-analysis.diff

@@ -1,5 +1,5 @@
-- // MIR for `main` before SimplifyCfg-early-opt
+- // MIR for `main` before SimplifyCfg-post-analysis
-+ // MIR for `main` after SimplifyCfg-early-opt
++ // MIR for `main` after SimplifyCfg-post-analysis
   
   fn main() -> () {
       let mut _0: ();

tests/mir-opt/simplify_cfg.rs

@@ -4,7 +4,7 @@
 //@ no-prefer-dynamic
 
 // EMIT_MIR simplify_cfg.main.SimplifyCfg-initial.diff
-// EMIT_MIR simplify_cfg.main.SimplifyCfg-early-opt.diff
+// EMIT_MIR simplify_cfg.main.SimplifyCfg-post-analysis.diff
 fn main() {
     loop {
         if bar() {