[PATCH] D112338: [InstCombine] Fold `(~(a | b) & c) | ~(a | c)` into `~((b & c) | a)`
Stanislav Mekhanoshin via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Fri Oct 22 12:09:52 PDT 2021
rampitec created this revision.
rampitec added a reviewer: spatel.
Herald added a subscriber: hiraditya.
rampitec requested review of this revision.
Herald added a project: LLVM.
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define i4 @src(i4 %a, i4 %b, i4 %c) {
%or1 = or i4 %b, %a
%not1 = xor i4 %or1, -1
%or2 = or i4 %a, %c
%not2 = xor i4 %or2, -1
%and = and i4 %not2, %b
%or3 = or i4 %and, %not1
ret i4 %or3
}
define i4 @tgt(i4 %a, i4 %b, i4 %c) {
%and = and i4 %c, %b
%or = or i4 %and, %a
%or3 = xor i4 %or, -1
ret i4 %or3
}
Transformation seems to be correct!
https://reviews.llvm.org/D112338
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
@@ -927,12 +927,9 @@
define i32 @or_and_not_not(i32 %a, i32 %b, i32 %c) {
; CHECK-LABEL: @or_and_not_not(
-; CHECK-NEXT: [[OR1:%.*]] = or i32 [[B:%.*]], [[A:%.*]]
-; CHECK-NEXT: [[NOT1:%.*]] = xor i32 [[OR1]], -1
-; CHECK-NEXT: [[OR2:%.*]] = or i32 [[A]], [[C:%.*]]
-; CHECK-NEXT: [[NOT2:%.*]] = xor i32 [[OR2]], -1
-; CHECK-NEXT: [[AND:%.*]] = and i32 [[NOT2]], [[B]]
-; CHECK-NEXT: [[OR3:%.*]] = or i32 [[AND]], [[NOT1]]
+; CHECK-NEXT: [[TMP1:%.*]] = and i32 [[C:%.*]], [[B:%.*]]
+; CHECK-NEXT: [[TMP2:%.*]] = or i32 [[TMP1]], [[A:%.*]]
+; CHECK-NEXT: [[OR3:%.*]] = xor i32 [[TMP2]], -1
; CHECK-NEXT: ret i32 [[OR3]]
;
%or1 = or i32 %b, %a
@@ -946,12 +943,9 @@
define i32 @or_and_not_not_commute1(i32 %a, i32 %b, i32 %c) {
; CHECK-LABEL: @or_and_not_not_commute1(
-; CHECK-NEXT: [[OR1:%.*]] = or i32 [[B:%.*]], [[A:%.*]]
-; CHECK-NEXT: [[NOT1:%.*]] = xor i32 [[OR1]], -1
-; CHECK-NEXT: [[OR2:%.*]] = or i32 [[A]], [[C:%.*]]
-; CHECK-NEXT: [[NOT2:%.*]] = xor i32 [[OR2]], -1
-; CHECK-NEXT: [[AND:%.*]] = and i32 [[NOT2]], [[B]]
-; CHECK-NEXT: [[OR3:%.*]] = or i32 [[AND]], [[NOT1]]
+; CHECK-NEXT: [[TMP1:%.*]] = and i32 [[C:%.*]], [[B:%.*]]
+; CHECK-NEXT: [[TMP2:%.*]] = or i32 [[TMP1]], [[A:%.*]]
+; CHECK-NEXT: [[OR3:%.*]] = xor i32 [[TMP2]], -1
; CHECK-NEXT: ret i32 [[OR3]]
;
%or1 = or i32 %b, %a
@@ -965,12 +959,9 @@
define i32 @or_and_not_not_commute2(i32 %a, i32 %b, i32 %c) {
; CHECK-LABEL: @or_and_not_not_commute2(
-; CHECK-NEXT: [[OR1:%.*]] = or i32 [[B:%.*]], [[A:%.*]]
-; CHECK-NEXT: [[NOT1:%.*]] = xor i32 [[OR1]], -1
-; CHECK-NEXT: [[OR2:%.*]] = or i32 [[A]], [[C:%.*]]
-; CHECK-NEXT: [[NOT2:%.*]] = xor i32 [[OR2]], -1
-; CHECK-NEXT: [[AND:%.*]] = and i32 [[NOT2]], [[B]]
-; CHECK-NEXT: [[OR3:%.*]] = or i32 [[AND]], [[NOT1]]
+; CHECK-NEXT: [[TMP1:%.*]] = and i32 [[C:%.*]], [[B:%.*]]
+; CHECK-NEXT: [[TMP2:%.*]] = or i32 [[TMP1]], [[A:%.*]]
+; CHECK-NEXT: [[OR3:%.*]] = xor i32 [[TMP2]], -1
; CHECK-NEXT: ret i32 [[OR3]]
;
%or1 = or i32 %b, %a
Index: llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
===================================================================
--- llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -2796,6 +2796,18 @@
if (match(Op0, m_And(m_Or(m_Specific(Op1), m_Value(C)), m_Value(A))))
return BinaryOperator::CreateOr(Op1, Builder.CreateAnd(A, C));
+ // (~(A | B) & C) | ~(A | C) --> ~((B & C) | A)
+ if (match(Op0, m_OneUse(m_c_And(m_OneUse(m_Not(m_Or(m_Value(A), m_Value(B)))),
+ m_Value(C))))) {
+ if (match(Op1, m_OneUse(m_Not(m_c_Or(m_Specific(A), m_Specific(C))))))
+ return BinaryOperator::CreateNot(
+ Builder.CreateOr(Builder.CreateAnd(B, C), A));
+
+ if (match(Op1, m_OneUse(m_Not(m_c_Or(m_Specific(B), m_Specific(C))))))
+ return BinaryOperator::CreateNot(
+ Builder.CreateOr(Builder.CreateAnd(A, C), B));
+ }
+
if (Instruction *DeMorgan = matchDeMorgansLaws(I, Builder))
return DeMorgan;
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