ART: SBC: Support single exit loops with live_outs.
Support copying subgraphs with a single exit and live-outs -
values which are defined inside the subgraph and have uses outside.
Test: test-art-target, test-art-host.
Test: 530-checker-peel-unroll.
Change-Id: Id06a6f08d14c6e86f6437d662e24489f955e9edf
diff --git a/compiler/optimizing/superblock_cloner.h b/compiler/optimizing/superblock_cloner.h
index e093167..f211721 100644
--- a/compiler/optimizing/superblock_cloner.h
+++ b/compiler/optimizing/superblock_cloner.h
@@ -218,7 +218,7 @@
private:
// Fills the 'exits' vector with the subgraph exits.
- void SearchForSubgraphExits(ArenaVector<HBasicBlock*>* exits);
+ void SearchForSubgraphExits(ArenaVector<HBasicBlock*>* exits) const;
// Finds and records information about the area in the graph for which control flow (back edges,
// loops, dominators) needs to be adjusted.
@@ -240,6 +240,33 @@
void ResolveDataFlow();
//
+ // Helpers for live-outs processing and Subgraph-closed SSA.
+ //
+ // - live-outs - values which are defined inside the subgraph and have uses outside.
+ // - Subgraph-closed SSA - SSA form for which all the values defined inside the subgraph
+ // have no outside uses except for the phi-nodes in the subgraph exits.
+ //
+ // Note: now if the subgraph has live-outs it is only clonable if it has a single exit; this
+ // makes the subgraph-closed SSA form construction much easier.
+ //
+ // TODO: Support subgraphs with live-outs and multiple exits.
+ //
+
+ // For each live-out value 'val' in the region puts a record <val, val> into the map.
+ // Returns whether all of the instructions in the subgraph are clonable.
+ bool CollectLiveOutsAndCheckClonable(HInstructionMap* live_outs_) const;
+
+ // Constructs Subgraph-closed SSA; precondition - a subgraph has a single exit.
+ //
+ // For each live-out 'val' in 'live_outs_' map inserts a HPhi 'phi' into the exit node, updates
+ // the record in the map to <val, phi> and replaces all outside uses with this phi.
+ void ConstructSubgraphClosedSSA();
+
+ // Fixes the data flow for the live-out 'val' by adding a 'copy_val' input to the corresponding
+ // (<val, phi>) phi after the cloning is done.
+ void FixSubgraphClosedSSAAfterCloning();
+
+ //
// Helpers for CloneBasicBlock.
//
@@ -316,6 +343,8 @@
HLoopInformation* outer_loop_;
HBasicBlockSet outer_loop_bb_set_;
+ HInstructionMap live_outs_;
+
ART_FRIEND_TEST(SuperblockClonerTest, AdjustControlFlowInfo);
ART_FRIEND_TEST(SuperblockClonerTest, IsGraphConnected);