tree cd79db8b0092d990fd7d1f81f40b1f22d909ca43
parent aea4e6b1b9e3c1f99766b34b2b6a02515b5dd9b1
author Steven Perron <stevenperron@google.com> 1563919170 -0400
committer GitHub <noreply@github.com> 1563919170 -0400
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SSA rewriter: Don't use trivial phis (#2757)

When a phi candidate is marked as trivial, we are suppose to update all
of its uses to the reference the value that it is being folded to.
However, the code updates the uses misses `defs_at_block_`.  So at a
later time, the id for the trivial phi can reemerge.

Fixes #2744