Reviewers: Benedikt Meurer,
Message:
Could you take a look, please?
Description:
Do not reduce effect phis for loops.
This prevents eliminating effectful statements before the loop.
BUG=
Please review this at https://codereview.chromium.org/830923002/
Base URL: https://chromium.googlesource.com/v8/v8.git@master
Affected files (+16, -6 lines):
M src/compiler/control-reducer.cc
A + test/mjsunit/compiler/regress-ntl-effect.js
Index: src/compiler/control-reducer.cc
diff --git a/src/compiler/control-reducer.cc
b/src/compiler/control-reducer.cc
index
e738ccf24e82f874447cb4584a78b8c488e71a57..acb2f06b04ea116e9c1ccbbf08978e72ae49d532
100644
--- a/src/compiler/control-reducer.cc
+++ b/src/compiler/control-reducer.cc
@@ -403,6 +403,14 @@ class ControlReducerImpl {
if (n <= 1) return dead(); // No non-control inputs.
if (n == 2) return node->InputAt(0); // Only one non-control input.
+ // Never remove an effect phi from a (potentially non-terminating)
loop.
+ // Otherwise, we might end up eliminating effect nodes, such as calls,
+ // before the loop.
+ if (node->opcode() == IrOpcode::kEffectPhi &&
+ NodeProperties::GetControlInput(node)->opcode() ==
IrOpcode::kLoop) {
+ return node;
+ }
+
Node* replacement = NULL;
Node::Inputs inputs = node->inputs();
for (InputIter it = inputs.begin(); n > 1; --n, ++it) {
Index: test/mjsunit/compiler/regress-ntl-effect.js
diff --git a/test/mjsunit/regress/regress-crbug-387636.js
b/test/mjsunit/compiler/regress-ntl-effect.js
similarity index 51%
copy from test/mjsunit/regress/regress-crbug-387636.js
copy to test/mjsunit/compiler/regress-ntl-effect.js
index
1e50ace45a293c8561042f1a09c8fcd505b43dc2..708fe32828c9197dfa3d8c371ab01cbc1ad3317a
100644
--- a/test/mjsunit/regress/regress-crbug-387636.js
+++ b/test/mjsunit/compiler/regress-ntl-effect.js
@@ -1,14 +1,16 @@
-// Copyright 2014 the V8 project authors. All rights reserved.
+// Copyright 2015 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Flags: --allow-natives-syntax
+function g() {
+ throw 0;
+}
+
function f() {
- [].indexOf(0x40000000);
+ g();
+ while (1) {}
}
-f();
-f();
-%OptimizeFunctionOnNextCall(f);
-f();
+assertThrows(function () { f(); });
--
--
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