Fix the effects of array.copy (#4118)

This appeared to be a regression from #4117, however this
was always a bug, and that PR just exposed it. That is,
somehow we forgot to indicate the effects of ArrayCopy, and
after that PR we'd vacuum it out incorrectly.

1 files changed, 2 insertions, 0 deletions

diff --git a/src/ir/effects.h b/src/ir/effects.h
index b9393ade2..475e6f2b1 100644
--- a/src/ir/effects.h
+++ b/src/ir/effects.h
@@ -659,6 +659,8 @@ private:
       }
     }
     void visitArrayCopy(ArrayCopy* curr) {
+      parent.readsArray = true;
+      parent.writesArray = true;
       // traps when a ref is null, or when out of bounds.
       parent.implicitTrap = true;
     }