From dd018df8a00e841fe38fabe38520b7d297a885c1 Mon Sep 17 00:00:00 2001 From: Igor Murashkin Date: Wed, 9 Aug 2017 10:38:31 -0700 Subject: optimizing: add block-scoped constructor fence merging pass Introduce a new "Constructor Fence Redundancy Elimination" pass. The pass currently performs local optimization only, i.e. within instructions in the same basic block. All constructor fences preceding a publish (e.g. store, invoke) get merged into one instruction. ============== OptStat#ConstructorFenceGeneratedNew: 43825 OptStat#ConstructorFenceGeneratedFinal: 17631 <+++ OptStat#ConstructorFenceRemovedLSE: 164 OptStat#ConstructorFenceRemovedPFRA: 9391 OptStat#ConstructorFenceRemovedCFRE: 16133 <--- Removes ~91.5% of the 'final' constructor fences in RitzBenchmark: (We do not distinguish the exact reason that a fence was created, so it's possible some "new" fences were also removed.) ============== Test: art/test/run-test --host --optimizing 476-checker-ctor-fence-redun-elim Bug: 36656456 Change-Id: I8020217b448ad96ce9b7640aa312ae784690ad99 --- compiler/optimizing/code_sinking.cc | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'compiler/optimizing/code_sinking.cc') diff --git a/compiler/optimizing/code_sinking.cc b/compiler/optimizing/code_sinking.cc index 6c3a9fd6b5..b558eb17a7 100644 --- a/compiler/optimizing/code_sinking.cc +++ b/compiler/optimizing/code_sinking.cc @@ -64,6 +64,11 @@ static bool IsInterestingInstruction(HInstruction* instruction) { // A fence with "0" inputs is dead and should've been removed in a prior pass. DCHECK_NE(0u, ctor_fence->InputCount()); + // TODO: this should be simplified to 'return true' since it's + // potentially pessimizing any code sinking for inlined constructors with final fields. + // TODO: double check that if the final field assignments are not moved, + // then the fence is not moved either. + return ctor_fence->GetAssociatedAllocation() != nullptr; } -- cgit v1.2.3-59-g8ed1b