Ryotaro Kasuga 2dbff02fad [LoopInterchange] Fix handling of PHI which refers to another PHI (#194364) ...

In the transformation phase, at first LoopInterchange moves several
instructions in the inner loop into the new latch block. The
instructions used as incoming values to the induction variables from the
latch block are the targets of this movement. Previously, this process
could result in an infinite loop when a PHI node refers to another PHI
node, as in the following example:

```
%i = phi i64 [ 0, %entry ], [ %i.inc, %latch ]
%j = phi i64 [ 0, %entry ], [ %i, %latch ]
```

The root cause was that `%i` enqueued for processing because it is used
by `%j`.
This patch fixes the issue by preventing induction variables from being
enqueued into the movement list.
Fix #193733

2026-04-30 11:07:27 +00:00

93 KiB

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