Michael Gottesman 0c7f5b3064 [cast-opt] Change optimizeMetatypeConversion to return a value and use the new ...

replace value uses action to make sure that we properly notify passes that we
made the change.

This fixes a latent bug where we were not notifying SILCombine about this
replacement.

Specifically:

-  auto replaceCast = [&](SingleValueInstruction *NewCast) {
-    assert(Ty.getAs<AnyMetatypeType>()->getRepresentation()
-           == NewCast->getType().getAs<AnyMetatypeType>()->getRepresentation());
-    MCI->replaceAllUsesWith(NewCast);
-    EraseInstAction(MCI);
-    return NewCast;
+  auto replaceCast = [&](SILValue newValue) -> SILValue {
+    assert(ty.getAs<AnyMetatypeType>()->getRepresentation() ==
+           newValue->getType().getAs<AnyMetatypeType>()->getRepresentation());
+    ReplaceValueUsesAction(mci, newValue);
+    EraseInstAction(mci);
+    return newValue;
   };

Notice how we use MCI->replaceAllUsesWith instead of one of our replace call
backs. SILCombine hooks these to know if it should re-run users.

2019-02-04 16:13:07 -08:00

7.0 KiB

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