[PATCH] D118094: [InstCombine] Implementing (x & y) + ~(x | y) -> ~(x ^ y)

[Chuanqi Xu via Phabricator via llvm-commits]

ChuanqiXu updated this revision to Diff 402792.
ChuanqiXu edited the summary of this revision.
ChuanqiXu added a reviewer: lebedev.ri.
ChuanqiXu added a comment.

Address comments.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D118094/new/

https://reviews.llvm.org/D118094

Files:
  llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
  llvm/test/Transforms/InstCombine/pr53357.ll


Index: llvm/test/Transforms/InstCombine/pr53357.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/InstCombine/pr53357.ll
@@ -0,0 +1,32 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; Test for (x & y) + ~(x | y) -> ~(x ^ y)
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+
+; (x & y) + ~(x | y)
+define dso_local i32 @src(i32 noundef %0, i32 noundef %1) local_unnamed_addr #0 {
+  %3 = and i32 %1, %0
+  %4 = or i32 %1, %0
+  %5 = xor i32 %4, -1
+  %6 = add i32 %3, %5
+  ret i32 %6
+}
+; CHECK-LABEL: src
+; CHECK-NEXT: %[[XOR:.+]] = xor i32 %1, %0
+; CHECK-NEXT: %[[XOR2:.+]] = xor i32 %[[XOR]], -1
+; CHECK-NEXT: ret i32 %[[XOR2]]
+
+
+; (x & y) + (~x & ~y)
+define dso_local i32 @src2(i32 noundef %0, i32 noundef %1) local_unnamed_addr #0 {
+  %3 = and i32 %1, %0
+  %4 = xor i32 %0, -1
+  %5 = xor i32 %1, -1
+  %6 = and i32 %4, %5
+  %7 = add i32 %3, %6
+  ret i32 %7
+}
+; CHECK-LABEL: src2
+; CHECK-NEXT: %[[XOR:.+]] = xor i32 %0, %1
+; CHECK-NEXT: %[[XOR2:.+]] = xor i32 %[[XOR]], -1
+; CHECK-NEXT: ret i32 %[[XOR2]]
Index: llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
===================================================================
--- llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
+++ llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
@@ -1342,6 +1342,11 @@
       match(&I, m_BinOp(m_c_Add(m_Not(m_Value(B)), m_Value(A)), m_One())))
     return BinaryOperator::CreateSub(A, B);
 
+  // (x & y) + ~(x | y) --> ~(x ^ y)
+  if (match(&I, m_c_BinOp(m_And(m_Value(A), m_Value(B)),
+                          m_Not(m_Or(m_Value(A), m_Value(B))))))
+    return BinaryOperator::CreateNot(Builder.CreateXor(A, B));
+
   // (A + RHS) + RHS --> A + (RHS << 1)
   if (match(LHS, m_OneUse(m_c_Add(m_Value(A), m_Specific(RHS)))))
     return BinaryOperator::CreateAdd(A, Builder.CreateShl(RHS, 1, "reass.add"));


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