Issue 12211128: Don't try to unlink instructions twice during GVN

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Issue 12211128: Don't try to unlink instructions twice during GVN (Closed)

Created:
7 years, 10 months ago by Sven Panne

Modified:
7 years, 10 months ago

Reviewers:
Michael Starzinger

CC:
v8-dev

Base URL:
https://v8.googlecode.com/svn/branches/bleeding_edge

Visibility:
Public.

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Description

Don't try to unlink instructions twice during GVN BUG=chrome:175141 Committed: http://code.google.com/p/v8/source/detail?r=13648

Patch Set 1 #

Total comments: 1

Created: 7 years, 10 months ago

Download [raw] [tar.bz2]

		Unified diffs	Side-by-side diffs	Delta from patch set	Stats (+2 lines, -1 line)			Patch
	M	src/hydrogen.cc	View		1 chunk	+2 lines, -1 line	1 comment	Download

Messages

Total messages: 2 (0 generated)

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Michael Starzinger

7 years, 10 months ago (2013-02-12 13:58:23 UTC) #2

LGTM.

https://codereview.chromium.org/12211128/diff/1/src/hydrogen.cc
File src/hydrogen.cc (right):

https://codereview.chromium.org/12211128/diff/1/src/hydrogen.cc#newcode2737
src/hydrogen.cc:2737: instr->SetSideEffectDominator(changes_flag, other);
There is another corner-case that is not yet covered. If
SetSideEffectDominator() removes the instruction from the graph, it might still
be present in the GVN map. This might lead to a subsequent call to
DeleteAndReplaceWith() where "other" is no longer in the graph.

I don't think this happens with the graphs we build ATM, but it is a general
problem when we allow SetSideEffectDominator() so delete instructions from the
graph. I am find with landing this change to fix the immediate problem though.

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