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
diff --git a/compiler/optimizing/pc_relative_fixups_x86.cc b/compiler/optimizing/pc_relative_fixups_x86.cc
index a385448..1394dfa 100644
--- a/compiler/optimizing/pc_relative_fixups_x86.cc
+++ b/compiler/optimizing/pc_relative_fixups_x86.cc
@@ -145,6 +145,11 @@
};
void PcRelativeFixups::Run() {
+ if (graph_->HasIrreducibleLoops()) {
+ // Do not run this optimization, as irreducible loops do not work with an instruction
+ // that can be live-in at the irreducible loop header.
+ return;
+ }
PCRelativeHandlerVisitor visitor(graph_);
visitor.VisitInsertionOrder();
visitor.MoveBaseIfNeeded();