[PATCH] D86395: [InstCombine] transform pattern "(~A & B) ^ A -> (A | B)" added

[Jaydeep Chauhan via Phabricator via llvm-commits]

Jac1494 updated this revision to Diff 291286.
Jac1494 added a comment.

test53 and test55 has been removed.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D86395/new/

https://reviews.llvm.org/D86395

Files:
  llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
  llvm/test/Transforms/InstCombine/xor.ll


Index: llvm/test/Transforms/InstCombine/xor.ll
===================================================================
--- llvm/test/Transforms/InstCombine/xor.ll
+++ llvm/test/Transforms/InstCombine/xor.ll
@@ -1179,9 +1179,7 @@
 ; CHECK-LABEL: @test52(
 ; CHECK-NEXT:    [[A:%.*]] = udiv i32 42, [[P1:%.*]]
 ; CHECK-NEXT:    [[B:%.*]] = udiv i32 42, [[P2:%.*]]
-; CHECK-NEXT:    [[O:%.*]] = xor i32 [[A]], -1
-; CHECK-NEXT:    [[R:%.*]] = and i32 [[B]], [[O]]
-; CHECK-NEXT:    [[Z:%.*]] = xor i32 [[R]], [[A]]
+; CHECK-NEXT:    [[Z:%.*]] = or i32 [[A]], [[B]]
 ; CHECK-NEXT:    ret i32 [[Z]]
 ;
   %a = udiv i32 42, %p1
@@ -1192,33 +1190,11 @@
   ret i32 %z
 }
 
-; (~B & A) ^ B  -->   (A | B)
-; The division ops are here to thwart complexity-based canonicalization: all ops are binops.
-
 define i32 @test53(i32 %p1, i32 %p2) {
 ; CHECK-LABEL: @test53(
 ; CHECK-NEXT:    [[A:%.*]] = udiv i32 42, [[P1:%.*]]
 ; CHECK-NEXT:    [[B:%.*]] = udiv i32 42, [[P2:%.*]]
-; CHECK-NEXT:    [[O:%.*]] = xor i32 [[B]], -1
-; CHECK-NEXT:    [[R:%.*]] = and i32 [[A]], [[O]]
-; CHECK-NEXT:    [[Z:%.*]] = xor i32 [[R]], [[B]]
-; CHECK-NEXT:    ret i32 [[Z]]
-;
-  %a = udiv i32 42, %p1
-  %b = udiv i32 42, %p2
-  %o = xor i32 %b, -1
-  %r = and i32 %o, %a
-  %z = xor i32 %r, %b
-  ret i32 %z
-}
-
-define i32 @test54(i32 %p1, i32 %p2) {
-; CHECK-LABEL: @test54(
-; CHECK-NEXT:    [[A:%.*]] = udiv i32 42, [[P1:%.*]]
-; CHECK-NEXT:    [[B:%.*]] = udiv i32 42, [[P2:%.*]]
-; CHECK-NEXT:    [[O:%.*]] = xor i32 [[A]], -1
-; CHECK-NEXT:    [[R:%.*]] = and i32 [[B]], [[O]]
-; CHECK-NEXT:    [[Z:%.*]] = xor i32 [[R]], [[A]]
+; CHECK-NEXT:    [[Z:%.*]] = or i32 [[A]], [[B]]
 ; CHECK-NEXT:    ret i32 [[Z]]
 ;
   %a = udiv i32 42, %p1
@@ -1228,20 +1204,3 @@
   %z = xor i32 %r, %a
   ret i32 %z
 }
-
-define i32 @test55(i32 %p1, i32 %p2) {
-; CHECK-LABEL: @test55(
-; CHECK-NEXT:    [[A:%.*]] = udiv i32 42, [[P1:%.*]]
-; CHECK-NEXT:    [[B:%.*]] = udiv i32 42, [[P2:%.*]]
-; CHECK-NEXT:    [[O:%.*]] = xor i32 [[A]], -1
-; CHECK-NEXT:    [[R:%.*]] = and i32 [[B]], [[O]]
-; CHECK-NEXT:    [[Z:%.*]] = xor i32 [[A]], [[R]]
-; CHECK-NEXT:    ret i32 [[Z]]
-;
-  %a = udiv i32 42, %p1
-  %b = udiv i32 42, %p2
-  %o = xor i32 %a, -1
-  %r = and i32 %o, %b
-  %z = xor i32 %a, %r
-  ret i32 %z
-}
Index: llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
===================================================================
--- llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -3371,6 +3371,10 @@
       match(Op1, m_Not(m_Specific(A))))
     return BinaryOperator::CreateNot(Builder.CreateAnd(A, B));
 
+  // (~A & B) ^ A  -->   (A | B) -- There are 4 commuted variants.
+  if (match(&I, m_c_Xor(m_c_And(m_Not(m_Value(A)), m_Value(B)), m_Deferred(A))))
+    return BinaryOperator::CreateOr(A, B);
+
   // (A | B) ^ (A | C) --> (B ^ C) & ~A -- There are 4 commuted variants.
   // TODO: Loosen one-use restriction if common operand is a constant.
   Value *D;


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