Commit Graph

14689 Commits

Author SHA1 Message Date
machenbach
b861a84009 Revert of ValueSerializer: Distinguish between 'undefined' and an absent property. (patchset #2 id:20001 of https://codereview.chromium.org/2660093002/ )
Reason for revert:
Seems to break layout tests:
https://build.chromium.org/p/client.v8.fyi/builders/V8-Blink%20Linux%2064/builds/13146

https://github.com/v8/v8/wiki/Blink-layout-tests

Original issue's description:
> ValueSerializer: Distinguish between 'undefined' and an absent property.
>
> Dealing with this case requires a wire format change. It is possible that an
> element can be absent even in an array where the dense format was chosen
> (because the array initially had no holes), if the elements are modified while
> they are being serialized. In this case, a new tag for the "hole" is emitted.
>
> The logic to treat undefined in dense arrays as an absent property is restricted
> to versions of the wire format that this tag did not exist.
>
> BUG=chromium:686159,chromium:665820
>
> Review-Url: https://codereview.chromium.org/2660093002
> Cr-Commit-Position: refs/heads/master@{#42784}
> Committed: dc85f4c833

TBR=jkummerow@chromium.org,jbroman@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:686159,chromium:665820

Review-Url: https://codereview.chromium.org/2667553003
Cr-Commit-Position: refs/heads/master@{#42788}
2017-01-30 19:35:28 +00:00
jochen
d651ce314c Add a test for OptimizingCompileDispatcher::Flush's non-blocking behavior
R=mtrofin@chromium.org,verwaest@chromium.org
BUG=

Review-Url: https://codereview.chromium.org/2662883003
Cr-Commit-Position: refs/heads/master@{#42787}
2017-01-30 19:27:00 +00:00
jbroman
dc85f4c833 ValueSerializer: Distinguish between 'undefined' and an absent property.
Dealing with this case requires a wire format change. It is possible that an
element can be absent even in an array where the dense format was chosen
(because the array initially had no holes), if the elements are modified while
they are being serialized. In this case, a new tag for the "hole" is emitted.

The logic to treat undefined in dense arrays as an absent property is restricted
to versions of the wire format that this tag did not exist.

BUG=chromium:686159,chromium:665820

Review-Url: https://codereview.chromium.org/2660093002
Cr-Commit-Position: refs/heads/master@{#42784}
2017-01-30 18:43:38 +00:00
jkummerow
7438304229 ThinStrings: fix Factory::NewProperSubString
BUG=chromium:685504

Review-Url: https://codereview.chromium.org/2660823002
Cr-Commit-Position: refs/heads/master@{#42783}
2017-01-30 18:24:16 +00:00
jkummerow
9ea3e56bd9 ThinStrings: fix CodeStubAssembler::SubString
BUG=chromium:685965

Review-Url: https://codereview.chromium.org/2660123002
Cr-Commit-Position: refs/heads/master@{#42782}
2017-01-30 18:17:52 +00:00
gdeepti
930142e877 [wasm] Update table bounds when module is instantiated with a table import
When WebAssembly.Table initial size is greater than the declared initial size, table size references should be updated on instantiate for functions to be called at indices greater than the declared initial size.

R=bradnelson@chromium.org, titzer@chromium.org

Review-Url: https://codereview.chromium.org/2661773002
Cr-Commit-Position: refs/heads/master@{#42781}
2017-01-30 18:10:32 +00:00
kozyatinskiy
3903817e0e [inspector] introduced memory size limit for console message storage
Without this CL we have only limit for amount of console messages and if user are dumping a huge messages we pretty soon run out of memory.
So let's introduce limit for memory consumption it would help chromium and Node.js as well.

BUG=chromium:671489
R=dgozman@chomium.org,alph@chromium.org, hpayer@chromium.org, ulan@chromium.org

Review-Url: https://codereview.chromium.org/2653293003
Cr-Commit-Position: refs/heads/master@{#42780}
2017-01-30 17:05:58 +00:00
jochen
1fc5ca85fc Fix --noopt to not optimize
BUG=v8:5904,chromium:639217
R=mstarzinger@chromium.org

Review-Url: https://codereview.chromium.org/2660103002
Cr-Commit-Position: refs/heads/master@{#42777}
2017-01-30 14:41:29 +00:00
petermarshall
f87ce44f52 [Test] Perform warmup first on SixSpeed super_spread benchmarks.
The graphs don't show any performance bump for
https://codereview.chromium.org/2659623002, which I do see a much better result for
locally. I suspect the function isn't being optimized in turbofan when the
benchmarks run. Maybe this warmup flag will trigger that.

BUG=v8:5895

Review-Url: https://codereview.chromium.org/2664783002
Cr-Commit-Position: refs/heads/master@{#42776}
2017-01-30 13:58:57 +00:00
mvstanton
93f05b64ae [TypeFeedbackVector] Combine the literals array and the feedback vector.
They have the same lifetime. It's a match!

Both structures are native context dependent and dealt with (creation,
clearing, gathering feedback) at the same time. By treating the spaces used
for literal boilerplates as feedback vector slots, we no longer have to keep
track of the materialized literal count elsewhere.

A follow-on CL removes even more parser infrastructure related to this count.

BUG=v8:5456

Review-Url: https://codereview.chromium.org/2655853010
Cr-Commit-Position: refs/heads/master@{#42771}
2017-01-30 12:31:35 +00:00
tebbi
8b6fa9d519 [turbofan] escape analysis reducer no longer confused by TypeGuards it introduced itself
R=bmeurer@chromium.org

BUG=chromium:682570

Review-Url: https://codereview.chromium.org/2664683003
Cr-Commit-Position: refs/heads/master@{#42769}
2017-01-30 11:51:22 +00:00
bmeurer
b912851650 [turbofan] Don't constant-fold ACCESSOR properties.
R=ishell@chromium.org
BUG=chromium:686102

Review-Url: https://codereview.chromium.org/2662793002
Cr-Commit-Position: refs/heads/master@{#42767}
2017-01-30 11:15:02 +00:00
petermarshall
409d018005 [turbofan] Reduce CallConstructWithSpread where iteration is not observable.
Where the arguments have already been inlined, we can replace these calls with a
direct call to construct. We have to make sure that the iteration over the arguments is not observable.

BUG=v8:5895

Review-Url: https://codereview.chromium.org/2659623002
Cr-Commit-Position: refs/heads/master@{#42765}
2017-01-30 10:29:05 +00:00
neis
5ed733737e [modules] Update a test and status file to reflect recent spec changes.
R=adamk@chromium.org
BUG=v8:1569

Review-Url: https://codereview.chromium.org/2657773006
Cr-Commit-Position: refs/heads/master@{#42763}
2017-01-30 09:41:15 +00:00
marja
0307bbb2a0 [parser] Skipping inner funcs: add tests for variables called "arguments"
These tests pass without further changes.

BUG=v8:5516

Review-Url: https://codereview.chromium.org/2654163008
Cr-Commit-Position: refs/heads/master@{#42762}
2017-01-30 09:09:38 +00:00
machenbach
a8638789c2 [test] Skip flaky test
BUG=v8:5906
NOTRY=true
TBR=binji@chromium.org

Review-Url: https://codereview.chromium.org/2659273002
Cr-Commit-Position: refs/heads/master@{#42759}
2017-01-29 12:52:05 +00:00
bradnelson
437735ed34 [wasm][asm.js] Make asm.js->wasm return a regular object.
Return a regular JSObject in the asm.js -> wasm case.

BUG=v8:5877
R=mtrofin@chromium.org,aseemgarg@chromium.org,titzer@chromium.org

Review-Url: https://codereview.chromium.org/2664493002
Cr-Commit-Position: refs/heads/master@{#42757}
2017-01-28 23:15:58 +00:00
jarin
6cd2d4ba41 [turbofan] Only use Tagged machine representation for tagged state values.
This avoids using kTaggedSigned and kTaggedPointer because the
semantic information of those type could be invalid in unreachable
code.

For example, SmiCheck(0.1) has representation TaggedSigned, but it is
later compiled to DeoptimizeUnless(ObjectIsSmi(0.1)) with the constant
0.1 directly connected to the uses. If the use is state-values, which
recorded the TaggedSigned representation of CheckSmi, the code
generator will be confused because it will see constant 0.1 that
claims to be TaggedSigned value.

BUG=chromium:675704

Review-Url: https://codereview.chromium.org/2656243004
Cr-Commit-Position: refs/heads/master@{#42756}
2017-01-28 17:25:46 +00:00
jbroman
bf511b426e ValueSerializer: Support efficiently reading and writing one-byte strings.
memcpy is faster than UTF-8 encoding/decoding. This yields 10-20% wins on
serializing and deserializing long ASCII strings, according to
blink_perf.bindings -- and these are already in a fast path where the entire
string is known to be ASCII (but this has to be checked). The win may be
larger for strings in Latin-1 but not ASCII (though I suspect this is an
uncommon case).

A change is also made to make ValueSerializerTest.EncodeTwoByteStringUsesPadding
survive wire format version number changes.

This is the first of a series of wire format changes from the previous Blink
format. The deserializer continues to be able to read the old format, but
Chromium M56 will no longer be able to read the messages written by this, in M58.

BUG=chromium:686159

Review-Url: https://codereview.chromium.org/2658793004
Cr-Commit-Position: refs/heads/master@{#42753}
2017-01-28 05:52:05 +00:00
binji
966355585b [d8] Use ValueSerializer for postMessage (instead of ad-hoc serializer)
Review-Url: https://codereview.chromium.org/2643723010
Cr-Commit-Position: refs/heads/master@{#42749}
2017-01-27 20:15:37 +00:00
marja
53667c89b0 [parser] Skipping inner funcs: produce correct data for var redeclarations.
This unifies the behavior of Scope::DeclareVariableName with
Scope::DeclareVariable.

BUG=v8:5516

Review-Url: https://codereview.chromium.org/2658063005
Cr-Commit-Position: refs/heads/master@{#42744}
2017-01-27 16:33:36 +00:00
ivica.bogosavljevic
2f728bd9a0 MIPS[64]: Prevent multiple instances of tests that require a lot of memory
Some tests require a lot of memory and they fail on buildbots if they run
in parallel with other tests of the same kind.
We try to limit this by disabling multiple vairants of the same tests,
assuming this would stop the failures in most of the cases.

BUG=

Review-Url: https://codereview.chromium.org/2653603002
Cr-Commit-Position: refs/heads/master@{#42741}
2017-01-27 14:15:59 +00:00
marja
92f36954bb [iwyu] Include handles.h less.
These headers only need forward declarations.

BUG=v8:5294

Review-Url: https://codereview.chromium.org/2654253002
Cr-Commit-Position: refs/heads/master@{#42740}
2017-01-27 13:53:13 +00:00
marja
2dac4588ee [parser] Skipping inner funcs: make basic variable declarations work.
BUG=v8:5516

Review-Url: https://codereview.chromium.org/2659053002
Cr-Commit-Position: refs/heads/master@{#42739}
2017-01-27 13:24:26 +00:00
tebbi
c1a43ff996 [turbofan] No longer ignore FrameState input to Call
R=mstarzinger@chromium.org

BUG=chromium:683566

Review-Url: https://codereview.chromium.org/2653953010
Cr-Commit-Position: refs/heads/master@{#42737}
2017-01-27 12:40:05 +00:00
bmeurer
b975441e77 [turbofan] Introduce dedicated StringIndexOf operator.
The StringIndexOf operation is pure on the JS level, but the actual stub
call must be in the effect chain later so that the Scheduler doesn't
place it inside some allocation region (The %StringIndexOf runtime
function may trigger a GC for string flattening).

BUG=chromium:685580
R=jarin@chromium.org

Review-Url: https://codereview.chromium.org/2657243002
Cr-Commit-Position: refs/heads/master@{#42736}
2017-01-27 12:02:42 +00:00
ishell
c5644146bc [tests] Fix assertUnoptimized() when --deopt-every-n-times flag is used.
Basically, with --deopt-every-n-times flag all bets are off since
the functions can be optimized and deoptimized at any time.

BUG=v8:5890

Review-Url: https://codereview.chromium.org/2655263004
Cr-Commit-Position: refs/heads/master@{#42735}
2017-01-27 11:58:47 +00:00
danno
5344571580 Make enabling of CSA verifier a build-time flag
BUG=chromium:685561

Review-Url: https://codereview.chromium.org/2650273006
Cr-Commit-Position: refs/heads/master@{#42734}
2017-01-27 11:32:27 +00:00
danno
7046c14d35 [csa] Make argc parameter to CodeStubArguments constructor use ParameterMode
Review-Url: https://codereview.chromium.org/2661483002
Cr-Commit-Position: refs/heads/master@{#42733}
2017-01-27 11:20:07 +00:00
ishell
4a5446fb2b [tests] Make assertOptimized()/assertUnoptimized() great again.
The mentioned asserts did not work properly with interpreted and turbofanned functions.

To fix this issue %GetOptimizationStatus() now returns a set of flags instead of a single value.

This CL also adds more helper functions to mjsunit, like isNeverOptimize(), isAlwaysOptimize(),
isOptimized(fun), etc.

BUG=v8:5890

Review-Url: https://codereview.chromium.org/2654733004
Cr-Original-Commit-Position: refs/heads/master@{#42703}
Committed: d1ddec7857
Review-Url: https://codereview.chromium.org/2654733004
Cr-Commit-Position: refs/heads/master@{#42731}
2017-01-27 10:13:53 +00:00
clemensh
e29a2cd529 [wasm] Interpreter: Don't pause on invalid position
Always execute the implicit return if we fell off the function bytes.
This is not considered an additional "step" as it is not executing a
wasm instruction.
Otherwise, we might pause at an invalid position (one after the
function bytes).

R=titzer@chromium.org
BUG=v8:5822

Review-Url: https://codereview.chromium.org/2650293003
Cr-Commit-Position: refs/heads/master@{#42730}
2017-01-27 09:48:08 +00:00
clemensh
b7947f8cd7 [wasm] Add inspector test for stepping
This also fixes bugs found by the new test. It only tests stepping
inside of wasm code. Wasm to JS and vice versa will follow in another
CL.

R=yangguo@chromium.org, titzer@chromium.org, kozyatinskiy@chromium.org
BUG=v8:5822

Review-Url: https://codereview.chromium.org/2651043004
Cr-Commit-Position: refs/heads/master@{#42729}
2017-01-27 08:50:50 +00:00
yangguo
3f47c63ded [liveedit] reimplement frame restarting.
Previously, when restarting a frame, we would rewrite all frames
between the debugger activation and the frame to restart to squash
them, and replace the return address with that of a builtin to
leave that rewritten frame, and restart the function by calling it.

We now simply remember the frame to drop to, and upon returning
from the debugger, we check whether to drop the frame, load the
new FP, and restart the function.

R=jgruber@chromium.org, mstarzinger@chromium.org
BUG=v8:5587

Review-Url: https://codereview.chromium.org/2636913002
Cr-Commit-Position: refs/heads/master@{#42725}
2017-01-27 07:31:03 +00:00
clemensh
c6663ef1c1 [inspector] Expose GetPossibleBreakpoints for wasm
and add an inspector test for it. Also test that a breakpoint can be
set on each reported position, and that it is also hit during
execution.
This CL also fixes two little things which were uncovered by the new
test.

R=yangguo@chromium.org, titzer@chromium.org, kozyatinskiy@chromium.org
BUG=v8:5822

Review-Url: https://codereview.chromium.org/2655653003
Cr-Commit-Position: refs/heads/master@{#42722}
2017-01-27 07:20:09 +00:00
alph
c99c25a988 [profiler] Fix a memory leak of CodeEvent objects
BUG=v8:5753

Review-Url: https://codereview.chromium.org/2655963003
Cr-Commit-Position: refs/heads/master@{#42720}
2017-01-27 01:12:53 +00:00
ahaas
2a78f2980b [x64] Do not compact constants with attached reloc info.
Reloc info often means that the constant will be patched later, and for
this patching we have to make sure that there is enough space in the
code for the new value.

R=bmeurer@chromium.org, titzer@chromium.org, gdeepti@chromium.org
BUG=chromium:684407
TEST=cctest/test-assembler-x64/Regression684407

Review-Url: https://codereview.chromium.org/2655213003
Cr-Commit-Position: refs/heads/master@{#42719}
2017-01-27 00:34:42 +00:00
gdeepti
e6d13999fd [wasm] Memory buffer should be detached after Memory.Grow
Memory.Grow should detach the ArrayBuffer associated with the Mem object after Grow. Currently, when guard pages are enabled protection is changed to make more of the buffer accessible. This does not work for when the buffer should be detached after grow, because the memory object has a reference to the same buffer befor/after grow.

R=titzer@chromium.org, eholk@chromium.org

Review-Url: https://codereview.chromium.org/2653183003
Cr-Commit-Position: refs/heads/master@{#42717}
2017-01-26 22:15:59 +00:00
kozyatinskiy
adc42c3a82 [inspector] take into account inlined frames in ::HasNonBlackboxedFrameOnStack
BUG=v8:5842, chromium:583193
R=yangguo@chromium.org,dgozman@chromium.org,alph@chromium.org

Review-Url: https://codereview.chromium.org/2656743003
Cr-Commit-Position: refs/heads/master@{#42715}
2017-01-26 21:32:53 +00:00
kozyatinskiy
0ac7970a60 [inspector] don't ignore uncaught exception if at least 1 frame isn't blackboxed
- and fixed test.

BUG=v8:5842, chromium:583193
R=yangguo@chromium.org,dgozman@chromium.org,alph@chromium.org

Review-Url: https://codereview.chromium.org/2651683005
Cr-Commit-Position: refs/heads/master@{#42714}
2017-01-26 20:57:03 +00:00
bmeurer
7be3b4c90f [turbofan] Don't try to optimize tail calls to .apply.
BUG=chromium:685634
R=ishell@chromium.org

Review-Url: https://codereview.chromium.org/2658853002
Cr-Commit-Position: refs/heads/master@{#42713}
2017-01-26 20:52:21 +00:00
mtrofin
70fdac9a64 [turbofan] Correct regalloc blocked register behavior
This corrects the case when we need to allocate a
blocked register, but the blockage happens after a
use as an instruction input, and there's no place to
split before that.

BUG=v8:5888

Review-Url: https://codereview.chromium.org/2652153005
Cr-Original-Commit-Position: refs/heads/master@{#42706}
Committed: ca779b29a6
Review-Url: https://codereview.chromium.org/2652153005
Cr-Commit-Position: refs/heads/master@{#42710}
2017-01-26 17:47:54 +00:00
ishell
a8a432701f [tests] Cleanup tests that use assertOptimized()/assertUnoptimized().
This CL adds --crankshaft and --no-always-opt flags to the tests that use
assertOptimized() and assertUnoptimized() respectively.

This CL also adds presubmit checks that ensure that tests have the proper
flags set.

BUG=v8:5890

Review-Url: https://codereview.chromium.org/2653753007
Cr-Commit-Position: refs/heads/master@{#42709}
2017-01-26 17:39:09 +00:00
ahaas
2b97f79afa Revert of [turbofan] Correct regalloc blocked register behavior (patchset #2 id:60001 of https://codereview.chromium.org/2652153005/ )
Reason for revert:
Introduces new crashers, e.g.

load("test/mjsunit/wasm/wasm-constants.js");
load("test/mjsunit/wasm/wasm-module-builder.js");

(function() {
  var builder = new WasmModuleBuilder();
  builder.addMemory(16, 32, false);
  builder.addFunction("test", kSig_i_iii)
    .addBodyWithEnd([
// body:
kExprI64Const, 0x42,
kExprI64Const, 0x7a,
kExprI64Ctz,
kExprI64Mul,
kExprI64Ctz,
kExprI64Const, 0x41,
kExprI64Ctz,
kExprI64Ctz,
kExprI64Shl,
kExprI64Const, 0x41,
kExprI64Ctz,
kExprI64Ctz,
kExprI64Shl,
kExprF32SConvertI64,
kExprUnreachable,
kExprEnd,   // @20
            ])
            .exportFunc();
  var module = builder.instantiate();
  module.exports.test(1, 2, 3);
})();

Original issue's description:
> [turbofan] Correct regalloc blocked register behavior
>
>
> This corrects the case when we need to allocate a
> blocked register, but the blockage happens after a
> use as an instruction input, and there's no place to
> split before that.
>
> BUG=v8:5888
>
> Review-Url: https://codereview.chromium.org/2652153005
> Cr-Commit-Position: refs/heads/master@{#42706}
> Committed: ca779b29a6

TBR=bmeurer@chromium.org,jarin@chromium.org,mtrofin@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:5888

Review-Url: https://codereview.chromium.org/2654993007
Cr-Commit-Position: refs/heads/master@{#42707}
2017-01-26 16:05:36 +00:00
mtrofin
ca779b29a6 [turbofan] Correct regalloc blocked register behavior
This corrects the case when we need to allocate a
blocked register, but the blockage happens after a
use as an instruction input, and there's no place to
split before that.

BUG=v8:5888

Review-Url: https://codereview.chromium.org/2652153005
Cr-Commit-Position: refs/heads/master@{#42706}
2017-01-26 15:51:47 +00:00
machenbach
d2d99e084a Revert of [tests] Make assertOptimized()/assertUnoptimized() great again. (patchset #6 id:130042 of https://codereview.chromium.org/2654733004/ )
Reason for revert:
Mac gc stress failures:
https://build.chromium.org/p/client.v8/builders/V8%20Mac%20GC%20Stress/builds/11195

There's also this flake, but maybe unrelated:
https://build.chromium.org/p/client.v8/builders/V8%20Win64/builds/15422

Original issue's description:
> [tests] Make assertOptimized()/assertUnoptimized() great again.
>
> The mentioned asserts did not work properly with interpreted and turbofanned functions.
>
> To fix this issue %GetOptimizationStatus() now returns a set of flags instead of a single value.
>
> This CL also adds more helper functions to mjsunit, like isNeverOptimize(), isAlwaysOptimize(),
> isOptimized(fun), etc.
>
> BUG=v8:5890
>
> Review-Url: https://codereview.chromium.org/2654733004
> Cr-Commit-Position: refs/heads/master@{#42703}
> Committed: d1ddec7857

TBR=mstarzinger@chromium.org,ishell@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:5890

Review-Url: https://codereview.chromium.org/2655223003
Cr-Commit-Position: refs/heads/master@{#42704}
2017-01-26 15:04:47 +00:00
ishell
d1ddec7857 [tests] Make assertOptimized()/assertUnoptimized() great again.
The mentioned asserts did not work properly with interpreted and turbofanned functions.

To fix this issue %GetOptimizationStatus() now returns a set of flags instead of a single value.

This CL also adds more helper functions to mjsunit, like isNeverOptimize(), isAlwaysOptimize(),
isOptimized(fun), etc.

BUG=v8:5890

Review-Url: https://codereview.chromium.org/2654733004
Cr-Commit-Position: refs/heads/master@{#42703}
2017-01-26 14:35:29 +00:00
mstarzinger
e752bcc216 [turbofan] Ensure {CheckMaps} is not used accross mutations.
This makes sure that static guarantees about object maps are not used
accross operations on the effect chain that might trigger a map change.
Such operations are missing the {Operator::kNoWrite} property.

R=bmeurer@chromium.org
TEST=mjsunit/regress/regress-crbug-685506
BUG=chromium:685506

Review-Url: https://codereview.chromium.org/2653273004
Cr-Commit-Position: refs/heads/master@{#42697}
2017-01-26 12:57:04 +00:00
marja
03e4381106 [parser] Skipping inner funcs: add variable names into the data for test purposes.
(Only in debug mode.)

BUG=v8:5516

Review-Url: https://codereview.chromium.org/2657943003
Cr-Commit-Position: refs/heads/master@{#42696}
2017-01-26 12:55:53 +00:00
cbruni
439a8edcf7 [builtins] Add String.prototype.indexOf fast path in TF
Review-Url: https://codereview.chromium.org/2638393002
Cr-Commit-Position: refs/heads/master@{#42695}
2017-01-26 12:46:44 +00:00
ahaas
55aed78210 [wasm] Fix constant folding with signalling NaN.
According to the WebAssembly spec no arithmetic operation should ever
return a signalling NaN. With the constant folding in V8, however, it
was possible that some arithmetic operations were elided, and if the
input of the arithmetic operation was a signalling NaN, then also the
result was the same signalling NaN. This CL removes some constant
folding optimizations and adjusts others so that even with constant
folding the result of an arithmetic operation is never a signalling NaN.

R=titzer@chromium.org, rossberg@chromium.org, bmeurer@chromium.org

Review-Url: https://codereview.chromium.org/2647353007
Cr-Commit-Position: refs/heads/master@{#42694}
2017-01-26 12:45:33 +00:00