[PATCH] D112108: [InstCombine] Fold `(a & ~b) & ~c` to `a & ~(b | c)`

[Stanislav Mekhanoshin via Phabricator via llvm-commits]

rampitec updated this revision to Diff 381034.
rampitec marked 3 inline comments as done.
rampitec added a comment.

Addressed review comments.
Pre-commited test and rebased.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D112108/new/

https://reviews.llvm.org/D112108

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


Index: llvm/test/Transforms/InstCombine/and-xor-or.ll
===================================================================
--- llvm/test/Transforms/InstCombine/and-xor-or.ll
+++ llvm/test/Transforms/InstCombine/and-xor-or.ll
@@ -522,10 +522,9 @@
 define i32 @not_and_and_not(i32 %a0, i32 %b, i32 %c) {
 ; CHECK-LABEL: @not_and_and_not(
 ; CHECK-NEXT:    [[A:%.*]] = sdiv i32 42, [[A0:%.*]]
-; CHECK-NEXT:    [[NOT1:%.*]] = xor i32 [[B:%.*]], -1
-; CHECK-NEXT:    [[NOT2:%.*]] = xor i32 [[C:%.*]], -1
-; CHECK-NEXT:    [[AND1:%.*]] = and i32 [[A]], [[NOT1]]
-; CHECK-NEXT:    [[AND2:%.*]] = and i32 [[AND1]], [[NOT2]]
+; CHECK-NEXT:    [[TMP1:%.*]] = or i32 [[B:%.*]], [[C:%.*]]
+; CHECK-NEXT:    [[TMP2:%.*]] = xor i32 [[TMP1]], -1
+; CHECK-NEXT:    [[AND2:%.*]] = and i32 [[A]], [[TMP2]]
 ; CHECK-NEXT:    ret i32 [[AND2]]
 ;
   %a = sdiv i32 42, %a0 ; thwart complexity-based canonicalization
@@ -539,10 +538,9 @@
 define <4 x i64> @not_and_and_not_4i64(<4 x i64> %a0, <4 x i64> %b, <4 x i64> %c) {
 ; CHECK-LABEL: @not_and_and_not_4i64(
 ; CHECK-NEXT:    [[A:%.*]] = sdiv <4 x i64> <i64 42, i64 42, i64 42, i64 42>, [[A0:%.*]]
-; CHECK-NEXT:    [[NOT1:%.*]] = xor <4 x i64> [[B:%.*]], <i64 -1, i64 -1, i64 -1, i64 -1>
-; CHECK-NEXT:    [[NOT2:%.*]] = xor <4 x i64> [[C:%.*]], <i64 -1, i64 -1, i64 -1, i64 -1>
-; CHECK-NEXT:    [[AND1:%.*]] = and <4 x i64> [[A]], [[NOT1]]
-; CHECK-NEXT:    [[AND2:%.*]] = and <4 x i64> [[AND1]], [[NOT2]]
+; CHECK-NEXT:    [[TMP1:%.*]] = or <4 x i64> [[B:%.*]], [[C:%.*]]
+; CHECK-NEXT:    [[TMP2:%.*]] = xor <4 x i64> [[TMP1]], <i64 -1, i64 -1, i64 -1, i64 -1>
+; CHECK-NEXT:    [[AND2:%.*]] = and <4 x i64> [[A]], [[TMP2]]
 ; CHECK-NEXT:    ret <4 x i64> [[AND2]]
 ;
   %a = sdiv <4 x i64> <i64 42, i64 42, i64 42, i64 42>, %a0 ; thwart complexity-based canonicalization
@@ -558,10 +556,9 @@
 define i32 @not_and_and_not_commute1(i32 %a0, i32 %b, i32 %c) {
 ; CHECK-LABEL: @not_and_and_not_commute1(
 ; CHECK-NEXT:    [[A:%.*]] = sdiv i32 42, [[A0:%.*]]
-; CHECK-NEXT:    [[NOT1:%.*]] = xor i32 [[B:%.*]], -1
-; CHECK-NEXT:    [[NOT2:%.*]] = xor i32 [[C:%.*]], -1
-; CHECK-NEXT:    [[AND1:%.*]] = and i32 [[A]], [[NOT1]]
-; CHECK-NEXT:    [[AND2:%.*]] = and i32 [[AND1]], [[NOT2]]
+; CHECK-NEXT:    [[TMP1:%.*]] = or i32 [[B:%.*]], [[C:%.*]]
+; CHECK-NEXT:    [[TMP2:%.*]] = xor i32 [[TMP1]], -1
+; CHECK-NEXT:    [[AND2:%.*]] = and i32 [[A]], [[TMP2]]
 ; CHECK-NEXT:    ret i32 [[AND2]]
 ;
   %a = sdiv i32 42, %a0 ; thwart complexity-based canonicalization
@@ -577,10 +574,9 @@
 define i32 @not_and_and_not_commute2(i32 %a0, i32 %b, i32 %c) {
 ; CHECK-LABEL: @not_and_and_not_commute2(
 ; CHECK-NEXT:    [[A:%.*]] = sdiv i32 42, [[A0:%.*]]
-; CHECK-NEXT:    [[NOT1:%.*]] = xor i32 [[B:%.*]], -1
-; CHECK-NEXT:    [[NOT2:%.*]] = xor i32 [[C:%.*]], -1
-; CHECK-NEXT:    [[AND1:%.*]] = and i32 [[A]], [[NOT1]]
-; CHECK-NEXT:    [[AND2:%.*]] = and i32 [[AND1]], [[NOT2]]
+; CHECK-NEXT:    [[TMP1:%.*]] = or i32 [[B:%.*]], [[C:%.*]]
+; CHECK-NEXT:    [[TMP2:%.*]] = xor i32 [[TMP1]], -1
+; CHECK-NEXT:    [[AND2:%.*]] = and i32 [[A]], [[TMP2]]
 ; CHECK-NEXT:    ret i32 [[AND2]]
 ;
   %a = sdiv i32 42, %a0 ; thwart complexity-based canonicalization
Index: llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
===================================================================
--- llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -2012,6 +2012,14 @@
     if (match(Op0, m_c_Xor(m_Not(m_Value(A)), m_Value(B))) &&
         match(Op1, m_c_Or(m_Specific(A), m_Specific(B))))
       return BinaryOperator::CreateAnd(A, B);
+
+    // (A & ~B) & ~C -> A & ~(B | C)
+    // (~B & A) & ~C -> A & ~(B | C)
+    if (match(Op0, m_c_And(m_Value(A), m_Not(m_Value(B)))))
+      if (match(Op1, m_Not(m_Value(C))))
+        if (Op0->hasOneUse())
+          return BinaryOperator::CreateAnd(
+              A, Builder.CreateNot(Builder.CreateOr(B, C)));
   }
 
   {


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