[llvm] r290067 - [InstCombine] use commutative matchers for patterns with commutative operators
Sanjay Patel via llvm-commits
llvm-commits at lists.llvm.org
Sun Dec 18 10:49:49 PST 2016
Author: spatel
Date: Sun Dec 18 12:49:48 2016
New Revision: 290067
URL: http://llvm.org/viewvc/llvm-project?rev=290067&view=rev
Log:
[InstCombine] use commutative matchers for patterns with commutative operators
Background/motivation - I was circling back around to:
https://llvm.org/bugs/show_bug.cgi?id=28296
I made a simple patch for that and noticed some regressions, so added test cases for
those with rL281055, and this is hopefully the minimal fix for just those cases.
But as you can see from the surrounding untouched folds, we are missing commuted patterns
all over the place, and of course there are no regression tests to cover any of those cases.
We could sprinkle "m_c_" dust all over this file and catch most of the missing folds, but
then we still wouldn't have test coverage, and we'd still miss some fraction of commuted
patterns because they require adjustments to the match order.
I'm aware of the concern about the potential compile-time performance impact of adding
matches like this (currently being discussed on llvm-dev), but I don't think there's any
evidence yet to suggest that handling commutative pattern matching more thoroughly is not
a worthwhile goal of InstCombine.
Differential Revision: https://reviews.llvm.org/D24419
Modified:
llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
llvm/trunk/test/Transforms/InstCombine/or-xor.ll
llvm/trunk/test/Transforms/InstCombine/or.ll
llvm/trunk/test/Transforms/InstCombine/xor2.ll
Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp?rev=290067&r1=290066&r2=290067&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp Sun Dec 18 12:49:48 2016
@@ -1345,6 +1345,9 @@ static Instruction *foldBoolSextMaskToSe
return nullptr;
}
+// FIXME: We use commutative matchers (m_c_*) for some, but not all, matches
+// here. We should standardize that construct where it is needed or choose some
+// other way to ensure that commutated variants of patterns are not missed.
Instruction *InstCombiner::visitAnd(BinaryOperator &I) {
bool Changed = SimplifyAssociativeOrCommutative(I);
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
@@ -1543,8 +1546,9 @@ Instruction *InstCombiner::visitAnd(Bina
return BinaryOperator::CreateAnd(A, B);
// ((~A) ^ B) & (A | B) -> (A & B)
+ // ((~A) ^ B) & (B | A) -> (A & B)
if (match(Op0, m_Xor(m_Not(m_Value(A)), m_Value(B))) &&
- match(Op1, m_Or(m_Specific(A), m_Specific(B))))
+ match(Op1, m_c_Or(m_Specific(A), m_Specific(B))))
return BinaryOperator::CreateAnd(A, B);
}
@@ -2161,6 +2165,9 @@ Instruction *InstCombiner::FoldXorWithCo
return nullptr;
}
+// FIXME: We use commutative matchers (m_c_*) for some, but not all, matches
+// here. We should standardize that construct where it is needed or choose some
+// other way to ensure that commutated variants of patterns are not missed.
Instruction *InstCombiner::visitOr(BinaryOperator &I) {
bool Changed = SimplifyAssociativeOrCommutative(I);
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
@@ -2250,8 +2257,9 @@ Instruction *InstCombiner::visitOr(Binar
match(Op1, m_Not(m_Specific(A))))
return BinaryOperator::CreateOr(Builder->CreateNot(A), B);
- // (A & (~B)) | (A ^ B) -> (A ^ B)
- if (match(Op0, m_And(m_Value(A), m_Not(m_Value(B)))) &&
+ // (A & ~B) | (A ^ B) -> (A ^ B)
+ // (~B & A) | (A ^ B) -> (A ^ B)
+ if (match(Op0, m_c_And(m_Value(A), m_Not(m_Value(B)))) &&
match(Op1, m_Xor(m_Specific(A), m_Specific(B))))
return BinaryOperator::CreateXor(A, B);
@@ -2427,14 +2435,15 @@ Instruction *InstCombiner::visitOr(Binar
return BinaryOperator::CreateOr(Not, Op0);
}
- // (A & B) | ((~A) ^ B) -> (~A ^ B)
- if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
- match(Op1, m_Xor(m_Not(m_Specific(A)), m_Specific(B))))
- return BinaryOperator::CreateXor(Builder->CreateNot(A), B);
-
- // ((~A) ^ B) | (A & B) -> (~A ^ B)
- if (match(Op0, m_Xor(m_Not(m_Value(A)), m_Value(B))) &&
- match(Op1, m_And(m_Specific(A), m_Specific(B))))
+ // (A & B) | (~A ^ B) -> (~A ^ B)
+ // (A & B) | (B ^ ~A) -> (~A ^ B)
+ // (B & A) | (~A ^ B) -> (~A ^ B)
+ // (B & A) | (B ^ ~A) -> (~A ^ B)
+ // The match order is important: match the xor first because the 'not'
+ // operation defines 'A'. We do not need to match the xor as Op0 because the
+ // xor was canonicalized to Op1 above.
+ if (match(Op1, m_c_Xor(m_Not(m_Value(A)), m_Value(B))) &&
+ match(Op0, m_c_And(m_Specific(A), m_Specific(B))))
return BinaryOperator::CreateXor(Builder->CreateNot(A), B);
if (SwappedForXor)
@@ -2514,6 +2523,9 @@ Instruction *InstCombiner::visitOr(Binar
return Changed ? &I : nullptr;
}
+// FIXME: We use commutative matchers (m_c_*) for some, but not all, matches
+// here. We should standardize that construct where it is needed or choose some
+// other way to ensure that commutated variants of patterns are not missed.
Instruction *InstCombiner::visitXor(BinaryOperator &I) {
bool Changed = SimplifyAssociativeOrCommutative(I);
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
@@ -2736,20 +2748,22 @@ Instruction *InstCombiner::visitXor(Bina
return BinaryOperator::CreateXor(A, B);
}
// (A | ~B) ^ (~A | B) -> A ^ B
- if (match(Op0I, m_Or(m_Value(A), m_Not(m_Value(B)))) &&
- match(Op1I, m_Or(m_Not(m_Specific(A)), m_Specific(B)))) {
+ // (~B | A) ^ (~A | B) -> A ^ B
+ if (match(Op0I, m_c_Or(m_Value(A), m_Not(m_Value(B)))) &&
+ match(Op1I, m_Or(m_Not(m_Specific(A)), m_Specific(B))))
return BinaryOperator::CreateXor(A, B);
- }
+
// (~A | B) ^ (A | ~B) -> A ^ B
if (match(Op0I, m_Or(m_Not(m_Value(A)), m_Value(B))) &&
match(Op1I, m_Or(m_Specific(A), m_Not(m_Specific(B))))) {
return BinaryOperator::CreateXor(A, B);
}
// (A & ~B) ^ (~A & B) -> A ^ B
- if (match(Op0I, m_And(m_Value(A), m_Not(m_Value(B)))) &&
- match(Op1I, m_And(m_Not(m_Specific(A)), m_Specific(B)))) {
+ // (~B & A) ^ (~A & B) -> A ^ B
+ if (match(Op0I, m_c_And(m_Value(A), m_Not(m_Value(B)))) &&
+ match(Op1I, m_And(m_Not(m_Specific(A)), m_Specific(B))))
return BinaryOperator::CreateXor(A, B);
- }
+
// (~A & B) ^ (A & ~B) -> A ^ B
if (match(Op0I, m_And(m_Not(m_Value(A)), m_Value(B))) &&
match(Op1I, m_And(m_Specific(A), m_Not(m_Specific(B))))) {
@@ -2785,9 +2799,10 @@ Instruction *InstCombiner::visitXor(Bina
return BinaryOperator::CreateOr(A, B);
}
- Value *A = nullptr, *B = nullptr;
- // (A & ~B) ^ (~A) -> ~(A & B)
- if (match(Op0, m_And(m_Value(A), m_Not(m_Value(B)))) &&
+ // (A & ~B) ^ ~A -> ~(A & B)
+ // (~B & A) ^ ~A -> ~(A & B)
+ Value *A, *B;
+ if (match(Op0, m_c_And(m_Value(A), m_Not(m_Value(B)))) &&
match(Op1, m_Not(m_Specific(A))))
return BinaryOperator::CreateNot(Builder->CreateAnd(A, B));
Modified: llvm/trunk/test/Transforms/InstCombine/or-xor.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/or-xor.ll?rev=290067&r1=290066&r2=290067&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/or-xor.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/or-xor.ll Sun Dec 18 12:49:48 2016
@@ -140,14 +140,9 @@ define i32 @test12(i32 %x, i32 %y) {
ret i32 %and
}
-; FIXME: We miss the fold because the pattern matching is inadequate.
-
define i32 @test12_commuted(i32 %x, i32 %y) {
; CHECK-LABEL: @test12_commuted(
-; CHECK-NEXT: [[NEG:%.*]] = xor i32 %x, -1
-; CHECK-NEXT: [[XOR:%.*]] = xor i32 [[NEG]], %y
-; CHECK-NEXT: [[OR:%.*]] = or i32 %y, %x
-; CHECK-NEXT: [[AND:%.*]] = and i32 [[XOR]], [[OR]]
+; CHECK-NEXT: [[AND:%.*]] = and i32 %x, %y
; CHECK-NEXT: ret i32 [[AND]]
;
%neg = xor i32 %x, -1
@@ -183,15 +178,9 @@ define i32 @test14(i32 %x, i32 %y) {
ret i32 %xor
}
-; FIXME: We miss the fold because the pattern matching is inadequate.
-
define i32 @test14_commuted(i32 %x, i32 %y) {
; CHECK-LABEL: @test14_commuted(
-; CHECK-NEXT: [[NOTY:%.*]] = xor i32 %y, -1
-; CHECK-NEXT: [[NOTX:%.*]] = xor i32 %x, -1
-; CHECK-NEXT: [[OR1:%.*]] = or i32 [[NOTY]], %x
-; CHECK-NEXT: [[OR2:%.*]] = or i32 [[NOTX]], %y
-; CHECK-NEXT: [[XOR:%.*]] = xor i32 [[OR1]], [[OR2]]
+; CHECK-NEXT: [[XOR:%.*]] = xor i32 %x, %y
; CHECK-NEXT: ret i32 [[XOR]]
;
%noty = xor i32 %y, -1
@@ -216,15 +205,9 @@ define i32 @test15(i32 %x, i32 %y) {
ret i32 %xor
}
-; FIXME: We miss the fold because the pattern matching is inadequate.
-
define i32 @test15_commuted(i32 %x, i32 %y) {
; CHECK-LABEL: @test15_commuted(
-; CHECK-NEXT: [[NOTY:%.*]] = xor i32 %y, -1
-; CHECK-NEXT: [[NOTX:%.*]] = xor i32 %x, -1
-; CHECK-NEXT: [[AND1:%.*]] = and i32 [[NOTY]], %x
-; CHECK-NEXT: [[AND2:%.*]] = and i32 [[NOTX]], %y
-; CHECK-NEXT: [[XOR:%.*]] = xor i32 [[AND1]], [[AND2]]
+; CHECK-NEXT: [[XOR:%.*]] = xor i32 %x, %y
; CHECK-NEXT: ret i32 [[XOR]]
;
%noty = xor i32 %y, -1
Modified: llvm/trunk/test/Transforms/InstCombine/or.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/or.ll?rev=290067&r1=290066&r2=290067&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/or.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/or.ll Sun Dec 18 12:49:48 2016
@@ -570,14 +570,10 @@ define i32 @test42(i32 %a, i32 %b) {
ret i32 %or
}
-; FIXME: We miss the fold because the pattern matching is inadequate.
-
define i32 @test42_commuted_and(i32 %a, i32 %b) {
; CHECK-LABEL: @test42_commuted_and(
-; CHECK-NEXT: [[NEGA:%.*]] = xor i32 %a, -1
-; CHECK-NEXT: [[XOR:%.*]] = xor i32 [[NEGA]], %b
-; CHECK-NEXT: [[AND:%.*]] = and i32 %b, %a
-; CHECK-NEXT: [[OR:%.*]] = or i32 [[XOR]], [[AND]]
+; CHECK-NEXT: [[TMP1:%.*]] = xor i32 %a, -1
+; CHECK-NEXT: [[OR:%.*]] = xor i32 [[TMP1]], %b
; CHECK-NEXT: ret i32 [[OR]]
;
%nega = xor i32 %a, -1
@@ -587,14 +583,10 @@ define i32 @test42_commuted_and(i32 %a,
ret i32 %or
}
-; FIXME: We miss the fold because the pattern matching is inadequate.
-
define i32 @test42_commuted_xor(i32 %a, i32 %b) {
; CHECK-LABEL: @test42_commuted_xor(
-; CHECK-NEXT: [[NEGA:%.*]] = xor i32 %a, -1
-; CHECK-NEXT: [[XOR:%.*]] = xor i32 %b, [[NEGA]]
-; CHECK-NEXT: [[AND:%.*]] = and i32 %a, %b
-; CHECK-NEXT: [[OR:%.*]] = or i32 [[XOR]], [[AND]]
+; CHECK-NEXT: [[TMP1:%.*]] = xor i32 %a, -1
+; CHECK-NEXT: [[OR:%.*]] = xor i32 [[TMP1]], %b
; CHECK-NEXT: ret i32 [[OR]]
;
%nega = xor i32 %a, -1
@@ -618,14 +610,9 @@ define i32 @test43(i32 %a, i32 %b) {
ret i32 %or
}
-; FIXME: We miss the fold because the pattern matching is inadequate.
-
define i32 @test43_commuted_and(i32 %a, i32 %b) {
; CHECK-LABEL: @test43_commuted_and(
-; CHECK-NEXT: [[NEG:%.*]] = xor i32 %b, -1
-; CHECK-NEXT: [[AND:%.*]] = and i32 [[NEG]], %a
-; CHECK-NEXT: [[XOR:%.*]] = xor i32 %a, %b
-; CHECK-NEXT: [[OR:%.*]] = or i32 [[AND]], [[XOR]]
+; CHECK-NEXT: [[OR:%.*]] = xor i32 %a, %b
; CHECK-NEXT: ret i32 [[OR]]
;
%neg = xor i32 %b, -1
Modified: llvm/trunk/test/Transforms/InstCombine/xor2.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/xor2.ll?rev=290067&r1=290066&r2=290067&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/xor2.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/xor2.ll Sun Dec 18 12:49:48 2016
@@ -180,14 +180,10 @@ define i32 @test12(i32 %a, i32 %b) {
ret i32 %xor
}
-; FIXME: We miss the fold because the pattern matching is inadequate.
-
define i32 @test12commuted(i32 %a, i32 %b) {
; CHECK-LABEL: @test12commuted(
-; CHECK-NEXT: [[NEGB:%.*]] = xor i32 %b, -1
-; CHECK-NEXT: [[AND:%.*]] = and i32 [[NEGB]], %a
-; CHECK-NEXT: [[NEGA:%.*]] = xor i32 %a, -1
-; CHECK-NEXT: [[XOR:%.*]] = xor i32 [[AND]], [[NEGA]]
+; CHECK-NEXT: [[TMP1:%.*]] = and i32 %a, %b
+; CHECK-NEXT: [[XOR:%.*]] = xor i32 [[TMP1]], -1
; CHECK-NEXT: ret i32 [[XOR]]
;
%negb = xor i32 %b, -1
@@ -198,7 +194,7 @@ define i32 @test12commuted(i32 %a, i32 %
}
; This is a test of canonicalization via operand complexity.
-; The final xor has a binary operator and a (fake) unary operator,
+; The final xor has a binary operator and a (fake) unary operator,
; so binary (more complex) should come first.
define i32 @test13(i32 %a, i32 %b) {
@@ -214,14 +210,10 @@ define i32 @test13(i32 %a, i32 %b) {
ret i32 %xor
}
-; FIXME: We miss the fold because the pattern matching is inadequate.
-
define i32 @test13commuted(i32 %a, i32 %b) {
; CHECK-LABEL: @test13commuted(
-; CHECK-NEXT: [[NEGA:%.*]] = xor i32 %a, -1
-; CHECK-NEXT: [[NEGB:%.*]] = xor i32 %b, -1
-; CHECK-NEXT: [[AND:%.*]] = and i32 [[NEGB]], %a
-; CHECK-NEXT: [[XOR:%.*]] = xor i32 [[AND]], [[NEGA]]
+; CHECK-NEXT: [[TMP1:%.*]] = and i32 %a, %b
+; CHECK-NEXT: [[XOR:%.*]] = xor i32 [[TMP1]], -1
; CHECK-NEXT: ret i32 [[XOR]]
;
%nega = xor i32 %a, -1
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