This adds a simple counter to Turbofan that's incremented throughout the compilation, hopefully
frequently enough so we can use it to detect divergence and performance bugs.
In addition, we assert that this counter never gets too high. That's the equivalent of a simple
timeout, just more deterministic. The limitations on Turbofan input size should guarantee that
we never exceed this limit. Since we probably do exceed it rarely, this check is only a DCHECK and
intended to detect performance and divergence issues, but not supposed to be performed in release
builds.

In addition, this CL adds UMA stats to observe the real world distribution of the tick measurement.

Bug: v8:9444

Change-Id: I182dac6ecac64715e3f5885ff5c7c17549351cd0
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1695475
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62754}

This is a reland of b8bc26d0

Original change's description:
> [turbofan] Preserve order of compares in switches
> 
> This CL makes sure that control flow optimization does
> not change the order of switches that ultimately get
> lowered to a series of comparisons anyway.
> 
> Bug: v8:7326
> Change-Id: If004de6b71a7e9504d37754c847ca108a64e49db
> Reviewed-on: https://chromium-review.googlesource.com/941952
> Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
> Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
> Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#51679}

Bug: v8:7326
Change-Id: Ifbe61dece499c98bbd49fa3ae9b99ccf4e955ddc
Reviewed-on: https://chromium-review.googlesource.com/945770Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51691}

This reverts commit b8bc26d0.

Reason for revert: may break node.js integration

Original change's description:
> [turbofan] Preserve order of compares in switches
> 
> This CL makes sure that control flow optimization does
> not change the order of switches that ultimately get
> lowered to a series of comparisons anyway.
> 
> Bug: v8:7326
> Change-Id: If004de6b71a7e9504d37754c847ca108a64e49db
> Reviewed-on: https://chromium-review.googlesource.com/941952
> Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
> Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
> Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#51679}

TBR=jarin@chromium.org,sigurds@chromium.org,bmeurer@chromium.org

Change-Id: Ideb551e0831c686dc7c247b77f59ff3485c30181
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:7326
Reviewed-on: https://chromium-review.googlesource.com/945768Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51681}

This CL makes sure that control flow optimization does
not change the order of switches that ultimately get
lowered to a series of comparisons anyway.

Bug: v8:7326
Change-Id: If004de6b71a7e9504d37754c847ca108a64e49db
Reviewed-on: https://chromium-review.googlesource.com/941952Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51679}

When trying to clone a branch, the ControlFlowOptimizer gave up as soon as it found a Phi/EffectPhi node that could not be placed directly below the IfTrue or IfFalse control paths.

Moving the step in the EffectControlLinearizer phase, after the first schedule, works around the problem by looking at the successor blocks.

BUG=

Review-Url: https://codereview.chromium.org/2139593002
Cr-Commit-Position: refs/heads/master@{#37687}

This introduces the NodeProperties::ChangeOp helper which guards node
operator changes so that additional checking can be done without any
additional dependencies being pulled into the Node class. For now only
the input count is checked, but additional checking might follow.

R=jarin@chromium.org

Review URL: https://codereview.chromium.org/1366753003

Cr-Commit-Position: refs/heads/master@{#30916}

The control flow optimization should work independent of the JSGraph. We
used the JSGraph there because it was convinient, not because it was
necessary.

R=jarin@chromium.org

Review URL: https://codereview.chromium.org/1160863003

Cr-Commit-Position: refs/heads/master@{#28674}

R=bmeurer@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1054963002

Cr-Commit-Position: refs/heads/master@{#27613}

R=mstarzinger@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1032553006

Cr-Commit-Position: refs/heads/master@{#27401}

Review URL: https://codereview.chromium.org/971223002

Cr-Commit-Position: refs/heads/master@{#26949}

R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/929403004

Cr-Commit-Position: refs/heads/master@{#26840}

This implements a special case of block cloning to recognize constructs like

 if (a ? b : c) { ... }

that happen to be generated by Emscripten quite often.

Review URL: https://codereview.chromium.org/947963002

Cr-Commit-Position: refs/heads/master@{#26808}

R=bmeurer@chromium.org
TEST=unittests/NodePropertiesTest.CollectControlProjections

Review URL: https://codereview.chromium.org/935033004

Cr-Commit-Position: refs/heads/master@{#26720}

This adds a new ControlFlowOptimizer that - for now - recognizes chains
of Branches generated by the SwitchBuilder for a subset of javascript
switches into Switch nodes. Those Switch nodes are then lowered to
either table or lookup switches.

Also rename Case to IfValue (and introduce IfDefault) for consistency.

BUG=v8:3872
LOG=n

Review URL: https://codereview.chromium.org/931623002

Cr-Commit-Position: refs/heads/master@{#26691}