[PATCH] D68128: [InstCombine] Fold PHIs with equal incoming pointers

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added inline comments.


================
Comment at: llvm/lib/Transforms/InstCombine/InstCombinePHI.cpp:1144-1155
+  for (Use &Incoming : PN.incoming_values()) {
+    if (!isa<Instruction>(Incoming))
+      return nullptr;
+    int64_t CurrentOffset;
+    bool IsCurrentInBounds = true;
+    Value *CurrentBase = GetPointerBaseWithConstantOffset(
+        Incoming, CurrentOffset, DL, /* AllowNonInbounds */ true,
----------------
This still looks like a hoisting problem to me, honestly.

In particular, why do we want *all* the incoming values to be identical?
I.e. why can't we track *which* values are identical,
and if there are two-or-more of of particular value hoist+common them?


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D68128/new/

https://reviews.llvm.org/D68128