Currently, decompression elimination may reduce phis by pushing decompressions in the value inputs of the phi "down" and replacing it by a single decompression following the phi node. Because of the way that the replacement is currently done, other reducers in the same phase will not generally get a chance to revisit the modified phi.

In the specific case of v8:9335 this blocked an additional optimization in CommonOperatorReducer from being applied, causing the overall load elimination test to fail.

This CL fixes the replacement behavior in decompression elimination to also allow for revisitations of the modified phi node.

Bug: v8:9335 v8:9336
Change-Id: I3ca5686dacb41a525160b08456905ba77cf28b39

Cq-Include-Trybots: luci.v8.try:v8_linux64_pointer_compression_rel_ng
Cq-Include-Trybots: luci.v8.try:v8_linux64_arm64_pointer_compression_rel_ng
Change-Id: I3ca5686dacb41a525160b08456905ba77cf28b39
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1648238Reviewed-by: Santiago Aboy Solanes <solanes@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Georg Schmid <gsps@google.com>
Cr-Commit-Position: refs/heads/master@{#62054}