Implement code sinking.
Small example of what the optimization does:
Object o = new Object();
if (test) {
throw new Error(o.toString());
}
will be turned into (note that the first user of 'o'
is the 'new Error' allocation which has 'o' in its
environment):
if (test) {
Object o = new Obect();
throw new Error(o.toString());
}
There are other examples in 639-checker-code-sinking.
Ritz individual benchmarks improve on art-jit-cc from
5% (EvaluateComplexFormulas) to 23% (MoveFunctionColumn)
on all platforms.
Test: 639-checker-code-sinking
Test: test-art-host
Test: borg job run
Test: libcore + jdwp
bug:35634932
bug:30933338
Change-Id: Ib99c00c93fe76ffffb17afffb5a0e30a14310652
diff --git a/compiler/optimizing/common_dominator.h b/compiler/optimizing/common_dominator.h
index b459d24..9f012cf 100644
--- a/compiler/optimizing/common_dominator.h
+++ b/compiler/optimizing/common_dominator.h
@@ -36,12 +36,16 @@
// Create a finder starting with a given block.
explicit CommonDominator(HBasicBlock* block)
: dominator_(block), chain_length_(ChainLength(block)) {
- DCHECK(block != nullptr);
}
// Update the common dominator with another block.
void Update(HBasicBlock* block) {
DCHECK(block != nullptr);
+ if (dominator_ == nullptr) {
+ dominator_ = block;
+ chain_length_ = ChainLength(block);
+ return;
+ }
HBasicBlock* block2 = dominator_;
DCHECK(block2 != nullptr);
if (block == block2) {