ART: Rediscover loops after deleting blocks in DCE
The way DCE currently updates loop information does not cover all
cases. This patch removes the logic, resets loop information of live
blocks to pre-SSA state and reanalyzes the affected loops.
Change-Id: I0b996a70235b95a8db0de9a23a03f71db57a21b8
diff --git a/compiler/optimizing/nodes.h b/compiler/optimizing/nodes.h
index 031761e..77b587e 100644
--- a/compiler/optimizing/nodes.h
+++ b/compiler/optimizing/nodes.h
@@ -436,6 +436,12 @@
// that is the header dominates the back edge.
bool Populate();
+ // Reanalyzes the loop by removing loop info from its blocks and re-running
+ // Populate(). If there are no back edges left, the loop info is completely
+ // removed as well as its SuspendCheck instruction. It must be run on nested
+ // inner loops first.
+ void Update();
+
// Returns whether this loop information contains `block`.
// Note that this loop information *must* be populated before entering this function.
bool Contains(const HBasicBlock& block) const;
@@ -705,14 +711,9 @@
loop_information_ = info;
}
- // Checks if the loop information points to a valid loop. If the loop has been
- // dismantled (does not have a back edge any more), loop information is
- // removed or replaced with the information of the first valid outer loop.
- void UpdateLoopInformation();
-
bool IsInLoop() const { return loop_information_ != nullptr; }
- // Returns wheter this block dominates the blocked passed as parameter.
+ // Returns whether this block dominates the blocked passed as parameter.
bool Dominates(HBasicBlock* block) const;
size_t GetLifetimeStart() const { return lifetime_start_; }