[PATCH] D67153: [InstCombine] Fold sub (or A, B) (and A, B) to (xor A, B)

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri accepted this revision.
lebedev.ri added a comment.
This revision is now accepted and ready to land.

LG.
There's also `sub(and(x, y), or(x, y)) -> neg(xor(x, y))`
https://rise4fun.com/Alive/VI6
https://godbolt.org/z/OMu71B



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Comment at: /home/xbolva00/LLVM/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp:1724
+    if (match(Op1, m_And(m_Value(A), m_Value(B))) &&
+        (match(Op0, m_c_Or(m_Specific(A), m_Specific(B)))))
+      return BinaryOperator::CreateXor(A, B);
----------------
extra unneeded braces


================
Comment at: test/Transforms/InstCombine/sub-or-and-xor.ll:69-78
+define i32 @sub_to_xor_and_commuted(i32 %x, i32 %y) {
+; CHECK-LABEL: @sub_to_xor_and_commuted(
+; CHECK-NEXT:    [[SUB:%.*]] = xor i32 [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    ret i32 [[SUB]]
+;
+  %or = or i32 %x, %y
+  %and = and i32 %y, %x
----------------
Precommit.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D67153/new/

https://reviews.llvm.org/D67153