[PATCH] D109515: [AggressiveInstCombine] Add `udiv` and `urem` instrs to TruncInstCombine DAG

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added a comment.

Seems reasonable.



================
Comment at: llvm/lib/Transforms/AggressiveInstCombine/TruncInstCombine.cpp:151
+      // 2. phi node(and loop handling)
       // ...
       return false;
----------------
sdiv, srem; see b289dc530632613edb3eb067895c1981cb77ccd0.


================
Comment at: llvm/lib/Transforms/AggressiveInstCombine/TruncInstCombine.cpp:314-323
+      KnownBits KnownLHS = computeKnownBits(I->getOperand(0));
+      unsigned MinBitWidth = KnownLHS.getMaxValue().getActiveBits();
+      if (MinBitWidth >= OrigBitWidth)
+        return nullptr;
+      KnownBits KnownRHS = computeKnownBits(I->getOperand(1));
+      MinBitWidth =
+          std::max(MinBitWidth, KnownRHS.getMaxValue().getActiveBits());
----------------



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https://reviews.llvm.org/D109515