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fix: [turbofan] Restrict redundancy elimination from widening types (#…
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patches/common/v8/turbofan_restrict_redundancy_elimination_from_widening_types.patch
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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 | ||
From: Sigurd Schneider <sigurds@chromium.org> | ||
Date: Mon, 7 Jan 2019 15:11:31 +0100 | ||
Subject: [turbofan] Restrict redundancy elimination from widening types | ||
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||
This CL prevents redundancy elimination from widening types, which | ||
can cause problems if the input of a DeadValue (which has type None) | ||
is replaced by an equivalent node that does not have type None. This | ||
can happen because load elimination does not re-type nodes, for | ||
example. | ||
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||
Bug: chromium:919340 | ||
Change-Id: I89e872412edbcdc610e70ae160cde56cd045006c | ||
Reviewed-on: https://chromium-review.googlesource.com/c/1397709 | ||
Reviewed-by: Tobias Tebbi <tebbi@chromium.org> | ||
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org> | ||
Commit-Queue: Sigurd Schneider <sigurds@chromium.org> | ||
Cr-Commit-Position: refs/heads/master@{#58617} | ||
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diff --git a/src/compiler/redundancy-elimination.cc b/src/compiler/redundancy-elimination.cc | ||
index 5ecef0408be4c849cccd695ccb8329ec7f27055e..8cc0501a22132e3c226294c53b047a473a8f9005 100644 | ||
--- a/src/compiler/redundancy-elimination.cc | ||
+++ b/src/compiler/redundancy-elimination.cc | ||
@@ -179,11 +179,22 @@ bool CheckSubsumes(Node const* a, Node const* b) { | ||
return true; | ||
} | ||
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+bool TypeSubsumes(Node* node, Node* replacement) { | ||
+ if (!NodeProperties::IsTyped(node) || !NodeProperties::IsTyped(replacement)) { | ||
+ // If either node is untyped, we are running during an untyped optimization | ||
+ // phase, and replacement is OK. | ||
+ return true; | ||
+ } | ||
+ Type node_type = NodeProperties::GetType(node); | ||
+ Type replacement_type = NodeProperties::GetType(replacement); | ||
+ return replacement_type.Is(node_type); | ||
+} | ||
+ | ||
} // namespace | ||
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||
Node* RedundancyElimination::EffectPathChecks::LookupCheck(Node* node) const { | ||
for (Check const* check = head_; check != nullptr; check = check->next) { | ||
- if (CheckSubsumes(check->node, node)) { | ||
+ if (CheckSubsumes(check->node, node) && TypeSubsumes(node, check->node)) { | ||
DCHECK(!check->node->IsDead()); | ||
return check->node; | ||
} | ||
diff --git a/test/mjsunit/regress/regress-919340.js b/test/mjsunit/regress/regress-919340.js | ||
new file mode 100644 | ||
index 0000000000000000000000000000000000000000..900bf6fde2f56bc328a17995c18a2fabd3f1023b | ||
--- /dev/null | ||
+++ b/test/mjsunit/regress/regress-919340.js | ||
@@ -0,0 +1,17 @@ | ||
+// Copyright 2019 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 --opt | ||
+ | ||
+var E = 'Σ'; | ||
+var PI = 123; | ||
+function f() { | ||
+ print(E = 2, /b/.test(E) || /b/.test(E = 2)); | ||
+ ((E = 3) * PI); | ||
+} | ||
+ | ||
+f(); | ||
+f(); | ||
+%OptimizeFunctionOnNextCall(f); | ||
+f(); |