[PATCH] D113783: [InstCombine] Fold (A^B)|~A-->~(A&B)

[Mehrnoosh Heidarpour via Phabricator via llvm-commits]

MehrHeidar created this revision.
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MehrHeidar requested review of this revision.
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This patch fixes bug ` Failure to simplify (A^B)|~A --> ~(A&B)` reported here: 
https://bugs.llvm.org/show_bug.cgi?id=52478


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D113783

Files:
  llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
  llvm/test/Transforms/InstCombine/and-or-icmps.ll
  llvm/test/Transforms/InstCombine/or-xor.ll


Index: llvm/test/Transforms/InstCombine/or-xor.ll
===================================================================
--- llvm/test/Transforms/InstCombine/or-xor.ll
+++ llvm/test/Transforms/InstCombine/or-xor.ll
@@ -61,0 +62,14 @@
+; ~X | (X ^ Y) --> ~(X & Y)
+
+define i32 @test5(i32 %x, i32 %y) {
+; CHECK-LABEL: @test5(
+; CHECK-NEXT:    [[TMP1:%.*]] = and i32 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[Z:%.*]] = xor i32 [[TMP1]], -1
+; CHECK-NEXT:    ret i32 [[Z]]
+;
+  %xor = xor i32 %x, %y
+  %notx = xor i32 %x, -1
+  %z = or i32 %xor, %notx
+  ret i32 %z
+}
+
Index: llvm/test/Transforms/InstCombine/and-or-icmps.ll
===================================================================
--- llvm/test/Transforms/InstCombine/and-or-icmps.ll
+++ llvm/test/Transforms/InstCombine/and-or-icmps.ll
@@ -372 +371,0 @@
-; CHECK-NEXT:    [[C11:%.*]] = icmp ne i16 [[L7]], 0
@@ -375 +374 @@
-; CHECK-NEXT:    [[B19:%.*]] = xor i1 [[C11]], [[B15]]
+; CHECK-NEXT:    [[C6:%.*]] = xor i1 [[B15]], true
@@ -377 +376 @@
-; CHECK-NEXT:    [[C3:%.*]] = and i1 [[TMP2]], [[B19]]
+; CHECK-NEXT:    [[C3:%.*]] = and i1 [[TMP2]], [[C6]]
Index: llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
===================================================================
--- llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -2675,0 +2676 @@
+  // ~A | (A ^ B) -> ~(A & B)
@@ -2684,0 +2686,4 @@
+    if (Op1->hasOneUse() &&
+        (match(Op0, m_Not(m_Specific(A))) || match(Op0, m_Not(m_Specific(B)))))
+      return BinaryOperator::CreateNot(Builder.CreateAnd(A, B));
+


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