Issue 23496017: Shr should save its Use truncating flag before Canonicalize

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Issue 23496017: Shr should save its Use truncating flag before Canonicalize (Closed)

Created:
7 years, 3 months ago by weiliang.lin2

Modified:
7 years, 3 months ago

Reviewers:
Jakob Kummerow

CC:
v8-dev

Base URL:
https://github.com/v8/v8.git@master

Visibility:
Public.

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Description

Shr should save its Use truncating flag before Canonicalize BUG= TEST=test/mjsunit/shr-truncating-nouint32.js

Patch Set 1 #

Created: 7 years, 3 months ago

Download [raw] [tar.bz2]

	Unified diffs	Side-by-side diffs	Stats (+13 lines, -17 lines)			Patch
M	src/arm/lithium-arm.cc	View	1 chunk	+1 line, -1 line	0 comments	Download
M	src/hydrogen-canonicalize.cc	View	1 chunk	+1 line, -1 line	0 comments	Download
M	src/ia32/lithium-ia32.cc	View	1 chunk	+1 line, -1 line	0 comments	Download
M	src/x64/lithium-x64.cc	View	1 chunk	+1 line, -1 line	0 comments	Download
A +	test/mjsunit/shr-truncating-nouint32.js	View	1 chunk	+9 lines, -13 lines	0 comments	Download

Messages

Total messages: 3 (0 generated)

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Jakob Kummerow

Well... the changes are generally fine, but I don't see the point of this CL. ...

7 years, 3 months ago (2013-08-29 10:42:44 UTC) #2

weiliang.lin2

7 years, 3 months ago (2013-08-30 06:43:06 UTC) #3

On 2013/08/29 10:42:44, Jakob wrote:
> Well... the changes are generally fine, but I don't see the point of this CL.
> The FLAG_opt_safe_uint32_operations flag has been turned on for a while, and I
> see no reason why we would turn it off again; so why should we spend time
(both
> engineering time, and a tiny bit of run time in HCanonicalizePhase::Run) on
the
> fallback code path?

Yes, it seems pointless to fix something on the fallback code path, especially
it will never be called. I found this issue when I tried to enable smi support
for Shr. For smi case, FLAG_opt_safe_uint32_operations is not useful and it
needs the fallback path to decide whether it will deopt.

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