[PATCH] D126617: [InstCombine] Optimize shl+lshr+and conversion pattern

[Sanjay Patel via Phabricator via llvm-commits]

spatel added inline comments.


================
Comment at: llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp:1892-1894
+    if (C->isPowerOf2() &&
+        match(Op0,
+              m_OneUse(m_LShr(m_Shl(m_APInt(C1), m_Value(X)), m_APInt(C2)))) &&
----------------
What happens if we reduce the pattern to:
https://alive2.llvm.org/ce/z/7snGRd

That's the same transform that I suggested in D126591, but invert the shift direction (lshr instead of shl).


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D126617/new/

https://reviews.llvm.org/D126617