Enable DestinationPropagation by default.

rust-lang · Apr 7, 2024 · aca6562 · aca6562
1 parent fc1a4c5
commit aca6562
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Showing 17 changed files with 292 additions and 551 deletions.
diff --git a/compiler/rustc_mir_transform/src/dest_prop.rs b/compiler/rustc_mir_transform/src/dest_prop.rs
@@ -159,7 +159,7 @@ impl<'tcx> MirPass<'tcx> for DestinationPropagation {
  // 2. Despite being an overall perf improvement, this still causes a 30% regression in
  // keccak. We can temporarily fix this by bounding function size, but in the long term
  // we should fix this by being smarter about invalidating analysis results.
- sess.mir_opt_level() >= 3
+ sess.mir_opt_level() >= 2
  }
 
  fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {

diff --git a/compiler/rustc_mir_transform/src/lib.rs b/compiler/rustc_mir_transform/src/lib.rs
@@ -90,7 +90,6 @@ mod match_branches;
 mod mentioned_items;
 mod multiple_return_terminators;
 mod normalize_array_len;
-mod nrvo;
 mod prettify;
 mod promote_consts;
 mod ref_prop;
@@ -598,13 +597,12 @@ fn run_optimization_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
  &jump_threading::JumpThreading,
  &early_otherwise_branch::EarlyOtherwiseBranch,
  &simplify_comparison_integral::SimplifyComparisonIntegral,
- &dest_prop::DestinationPropagation,
  &o1(simplify_branches::SimplifyConstCondition::Final),
  &o1(remove_noop_landing_pads::RemoveNoopLandingPads),
  &o1(simplify::SimplifyCfg::Final),
  &copy_prop::CopyProp,
  &dead_store_elimination::DeadStoreElimination::Final,
- &nrvo::RenameReturnPlace,
+ &dest_prop::DestinationPropagation,
  &simplify::SimplifyLocals::Final,
  &multiple_return_terminators::MultipleReturnTerminators,
  &deduplicate_blocks::DeduplicateBlocks,

diff --git a/compiler/rustc_mir_transform/src/nrvo.rs b/compiler/rustc_mir_transform/src/nrvo.rs
diff --git a/...e.nrvo.RenameReturnPlace.panic-abort.diff → ...o.DestinationPropagation.panic-abort.diff b/...e.nrvo.RenameReturnPlace.panic-abort.diff → ...o.DestinationPropagation.panic-abort.diff
@@ -1,5 +1,5 @@
-- // MIR for `nrvo` before RenameReturnPlace
-+ // MIR for `nrvo` after RenameReturnPlace
+- // MIR for `nrvo` before DestinationPropagation
++ // MIR for `nrvo` after DestinationPropagation
 
  fn nrvo(_1: for<'a> fn(&'a mut [u8; 1024])) -> [u8; 1024] {
  debug init => _1;
@@ -10,32 +10,33 @@
  let mut _5: &mut [u8; 1024];
  let mut _6: &mut [u8; 1024];
  scope 1 {
-- debug buf => _2;
-+ debug buf => _0;
+ debug buf => _2;
  }
 
  bb0: {
-- StorageLive(_2);
-- _2 = [const 0_u8; 1024];
-+ _0 = [const 0_u8; 1024];
+ StorageLive(_2);
+ _2 = [const 0_u8; 1024];
  StorageLive(_3);
- StorageLive(_4);
- _4 = _1;
+- StorageLive(_4);
+- _4 = _1;
++ nop;
++ nop;
  StorageLive(_5);
  StorageLive(_6);
-- _6 = &mut _2;
-+ _6 = &mut _0;
+ _6 = &mut _2;
  _5 = &mut (*_6);
- _3 = move _4(move _5) -> [return: bb1, unwind unreachable];
+- _3 = move _4(move _5) -> [return: bb1, unwind unreachable];
++ _3 = move _1(move _5) -> [return: bb1, unwind unreachable];
  }
 
  bb1: {
  StorageDead(_5);
- StorageDead(_4);
+- StorageDead(_4);
++ nop;
  StorageDead(_6);
  StorageDead(_3);
-- _0 = _2;
-- StorageDead(_2);
+  _0 = _2;
+  StorageDead(_2);
  return;
  }
  }

diff --git a/....nrvo.RenameReturnPlace.panic-unwind.diff → ....DestinationPropagation.panic-unwind.diff b/....nrvo.RenameReturnPlace.panic-unwind.diff → ....DestinationPropagation.panic-unwind.diff
@@ -1,5 +1,5 @@
-- // MIR for `nrvo` before RenameReturnPlace
-+ // MIR for `nrvo` after RenameReturnPlace
+- // MIR for `nrvo` before DestinationPropagation
++ // MIR for `nrvo` after DestinationPropagation
 
  fn nrvo(_1: for<'a> fn(&'a mut [u8; 1024])) -> [u8; 1024] {
  debug init => _1;
@@ -10,32 +10,33 @@
  let mut _5: &mut [u8; 1024];
  let mut _6: &mut [u8; 1024];
  scope 1 {
-- debug buf => _2;
-+ debug buf => _0;
+ debug buf => _2;
  }
 
  bb0: {
-- StorageLive(_2);
-- _2 = [const 0_u8; 1024];
-+ _0 = [const 0_u8; 1024];
+ StorageLive(_2);
+ _2 = [const 0_u8; 1024];
  StorageLive(_3);
- StorageLive(_4);
- _4 = _1;
+- StorageLive(_4);
+- _4 = _1;
++ nop;
++ nop;
  StorageLive(_5);
  StorageLive(_6);
-- _6 = &mut _2;
-+ _6 = &mut _0;
+ _6 = &mut _2;
  _5 = &mut (*_6);
- _3 = move _4(move _5) -> [return: bb1, unwind continue];
+- _3 = move _4(move _5) -> [return: bb1, unwind continue];
++ _3 = move _1(move _5) -> [return: bb1, unwind continue];
  }
 
  bb1: {
  StorageDead(_5);
- StorageDead(_4);
+- StorageDead(_4);
++ nop;
  StorageDead(_6);
  StorageDead(_3);
-- _0 = _2;
-- StorageDead(_2);
+  _0 = _2;
+  StorageDead(_2);
  return;
  }
  }

diff --git a/tests/mir-opt/nrvo_simple.rs → tests/mir-opt/dest-prop/nrvo_borrowed.rs b/tests/mir-opt/nrvo_simple.rs → tests/mir-opt/dest-prop/nrvo_borrowed.rs
@@ -1,8 +1,8 @@
 // skip-filecheck
 // EMIT_MIR_FOR_EACH_PANIC_STRATEGY
-//@ unit-test: RenameReturnPlace
+//@ unit-test: DestinationPropagation
 
-// EMIT_MIR nrvo_simple.nrvo.RenameReturnPlace.diff
+// EMIT_MIR nrvo_borrowed.nrvo.DestinationPropagation.diff
 fn nrvo(init: fn(&mut [u8; 1024])) -> [u8; 1024] {
  let mut buf = [0; 1024];
  init(&mut buf);

diff --git a/tests/mir-opt/dest-prop/union.main.DestinationPropagation.panic-abort.diff b/tests/mir-opt/dest-prop/union.main.DestinationPropagation.panic-abort.diff
@@ -18,7 +18,7 @@
  bb0: {
  StorageLive(_1);
  StorageLive(_2);
- _2 = const 1_u32;
+ nop;
  _1 = Un { us: const 1_u32 };
  StorageDead(_2);
  StorageLive(_3);