Each reducer now has a virtual reducer_name function, returning its name
(the name of the class containing this reducer). This gets displayed when
using the --trace_turbo_reduction flag. Also when using this flags more
messages are displayed.

Actually when a node is replaced in-place (which is called an update
of the node), other reducers can still update it right after the
in-place replacement. When a node is really replaced (not in-place),
then we stop trying to apply reducers to it before we propagate the
reduction through the relevant nodes.

Before a message got printed only for the last reduction it went
through. So in case a node was reduced in-place several times
in a row, only the last update was printed, or none at all if after
being reduced in-place it got reduced by being replaced by another
node: only the non-in-place replacement was showed. 

Now each time an in-place reduction is applied to a node, a message
gets printed.

Bug: 
Change-Id: Id0f816fecd44c01d0253966c6decc4861be0c2fa
Reviewed-on: https://chromium-review.googlesource.com/563365Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Alexandre Talon <alexandret@google.com>
Cr-Commit-Position: refs/heads/master@{#46552}

This has two parts:
- in redundancy elimination, if we see addition with left hand side that
  was bounds-checked, we reconnect the lhs to the bounds check if it has better
  type.
- in representation inference, eliminate overflow checks if the input types
  guarantee no overflow.

Review-Url: https://codereview.chromium.org/2527083002
Cr-Commit-Position: refs/heads/master@{#41260}

A pointer comparison on the effect path states is not sufficient to
guarantee termination; we really need to check the actual nodes to
make sure we terminate properly, similar to what BranchElimination
does.

R=jarin@chromium.org
BUG=v8:5161

Review-Url: https://codereview.chromium.org/2112463002
Cr-Commit-Position: refs/heads/master@{#37389}

The redundancy elimination is currently a graph reducer that tries to
combine redundant checks in the effect chain. It does this by
propagating the checks that happened along effect paths, which is pretty
similar to what the BranchElimination does on the control chain. We run
this reducer together with the other optimizations right after the
representation selection.

An upcoming CL will extend the redundancy elimination to also eliminate
redundant loads (and eventually map checks).

R=jarin@chromium.org
BUG=v8:5141

Review-Url: https://codereview.chromium.org/2091503003
Cr-Commit-Position: refs/heads/master@{#37208}