From 15bd22849ee6a1ffb3fb3630f686c2870bdf1bbc Mon Sep 17 00:00:00 2001 From: Nicolas Geoffray Date: Tue, 5 Jan 2016 15:55:41 +0000 Subject: Implement irreducible loop support in optimizing. So we don't fallback to the interpreter in the presence of irreducible loops. Implications: - A loop pre-header does not necessarily dominate a loop header. - Non-constant redundant phis will be kept in loop headers, to satisfy our linear scan register allocation algorithm. - while-graph optimizations, such as gvn, licm, lse, and dce need to know when they are dealing with irreducible loops. Change-Id: I2cea8934ce0b40162d215353497c7f77d6c9137e --- compiler/optimizing/induction_var_analysis.cc | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'compiler/optimizing/induction_var_analysis.cc') diff --git a/compiler/optimizing/induction_var_analysis.cc b/compiler/optimizing/induction_var_analysis.cc index eef6cef5f0..37f2d79536 100644 --- a/compiler/optimizing/induction_var_analysis.cc +++ b/compiler/optimizing/induction_var_analysis.cc @@ -76,7 +76,9 @@ void HInductionVarAnalysis::Run() { // range analysis on outer loop while visiting inner loops. for (HReversePostOrderIterator it_graph(*graph_); !it_graph.Done(); it_graph.Advance()) { HBasicBlock* graph_block = it_graph.Current(); - if (graph_block->IsLoopHeader()) { + // Don't analyze irreducible loops. + // TODO(ajcbik): could/should we remove this restriction? + if (graph_block->IsLoopHeader() && !graph_block->GetLoopInformation()->IsIrreducible()) { VisitLoop(graph_block->GetLoopInformation()); } } -- cgit v1.2.3-59-g8ed1b