[llvm] r310806 - [InstCombine] Simplify and inline FoldOrWithConstants/FoldXorWithConstants
Craig Topper via llvm-commits
llvm-commits at lists.llvm.org
Sun Aug 13 17:04:22 PDT 2017
Author: ctopper
Date: Sun Aug 13 17:04:21 2017
New Revision: 310806
URL: http://llvm.org/viewvc/llvm-project?rev=310806&view=rev
Log:
[InstCombine] Simplify and inline FoldOrWithConstants/FoldXorWithConstants
Summary:
These functions were overly complicated. The body of this function was rechecking for an And operation to find the constant, but we already knew we were looking at two Ands ORed together and the pieces are in variables. We already had earlier nearby code that checked for ConstantInts. So just inline the remaining parts into the earlier code.
Next step is to use m_APInt instead of ConstantInt.
Reviewers: spatel, efriedma, davide, majnemer
Reviewed By: spatel
Subscribers: zzheng, llvm-commits
Differential Revision: https://reviews.llvm.org/D36439
Modified:
llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp?rev=310806&r1=310805&r2=310806&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp Sun Aug 13 17:04:21 2017
@@ -1811,69 +1811,6 @@ Value *InstCombiner::foldOrOfFCmps(FCmpI
return nullptr;
}
-/// This helper function folds:
-///
-/// ((A | B) & C1) | (B & C2)
-///
-/// into:
-///
-/// (A & C1) | B
-///
-/// when the XOR of the two constants is "all ones" (-1).
-static Instruction *FoldOrWithConstants(BinaryOperator &I, Value *Op,
- Value *A, Value *B, Value *C,
- InstCombiner::BuilderTy &Builder) {
- ConstantInt *CI1 = dyn_cast<ConstantInt>(C);
- if (!CI1) return nullptr;
-
- Value *V1 = nullptr;
- ConstantInt *CI2 = nullptr;
- if (!match(Op, m_And(m_Value(V1), m_ConstantInt(CI2)))) return nullptr;
-
- APInt Xor = CI1->getValue() ^ CI2->getValue();
- if (!Xor.isAllOnesValue()) return nullptr;
-
- if (V1 == A || V1 == B) {
- Value *NewOp = Builder.CreateAnd((V1 == A) ? B : A, CI1);
- return BinaryOperator::CreateOr(NewOp, V1);
- }
-
- return nullptr;
-}
-
-/// \brief This helper function folds:
-///
-/// ((A ^ B) & C1) | (B & C2)
-///
-/// into:
-///
-/// (A & C1) ^ B
-///
-/// when the XOR of the two constants is "all ones" (-1).
-static Instruction *FoldXorWithConstants(BinaryOperator &I, Value *Op,
- Value *A, Value *B, Value *C,
- InstCombiner::BuilderTy &Builder) {
- ConstantInt *CI1 = dyn_cast<ConstantInt>(C);
- if (!CI1)
- return nullptr;
-
- Value *V1 = nullptr;
- ConstantInt *CI2 = nullptr;
- if (!match(Op, m_And(m_Value(V1), m_ConstantInt(CI2))))
- return nullptr;
-
- APInt Xor = CI1->getValue() ^ CI2->getValue();
- if (!Xor.isAllOnesValue())
- return nullptr;
-
- if (V1 == A || V1 == B) {
- Value *NewOp = Builder.CreateAnd(V1 == A ? B : A, CI1);
- return BinaryOperator::CreateXor(NewOp, V1);
- }
-
- 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.
@@ -1939,10 +1876,10 @@ Instruction *InstCombiner::visitOr(Binar
Value *C = nullptr, *D = nullptr;
if (match(Op0, m_And(m_Value(A), m_Value(C))) &&
match(Op1, m_And(m_Value(B), m_Value(D)))) {
- Value *V1 = nullptr, *V2 = nullptr;
ConstantInt *C1 = dyn_cast<ConstantInt>(C);
ConstantInt *C2 = dyn_cast<ConstantInt>(D);
if (C1 && C2) { // (A & C1)|(B & C2)
+ Value *V1 = nullptr, *V2 = nullptr;
if ((C1->getValue() & C2->getValue()).isNullValue()) {
// ((V | N) & C1) | (V & C2) --> (V|N) & (C1|C2)
// iff (C1&C2) == 0 and (N&~C1) == 0
@@ -1974,6 +1911,24 @@ Instruction *InstCombiner::visitOr(Binar
Builder.getInt(C1->getValue()|C2->getValue()));
}
}
+
+ if (C1->getValue() == ~C2->getValue()) {
+ Value *X;
+
+ // ((X|B)&C1)|(B&C2) -> (X&C1) | B iff C1 == ~C2
+ if (match(A, m_c_Or(m_Value(X), m_Specific(B))))
+ return BinaryOperator::CreateOr(Builder.CreateAnd(X, C1), B);
+ // (A&C2)|((X|A)&C1) -> (X&C2) | A iff C1 == ~C2
+ if (match(B, m_c_Or(m_Specific(A), m_Value(X))))
+ return BinaryOperator::CreateOr(Builder.CreateAnd(X, C2), A);
+
+ // ((X^B)&C1)|(B&C2) -> (X&C1) ^ B iff C1 == ~C2
+ if (match(A, m_c_Xor(m_Value(X), m_Specific(B))))
+ return BinaryOperator::CreateXor(Builder.CreateAnd(X, C1), B);
+ // (A&C2)|((X^A)&C1) -> (X&C2) ^ A iff C1 == ~C2
+ if (match(B, m_c_Xor(m_Specific(A), m_Value(X))))
+ return BinaryOperator::CreateXor(Builder.CreateAnd(X, C2), A);
+ }
}
// Don't try to form a select if it's unlikely that we'll get rid of at
@@ -1998,27 +1953,6 @@ Instruction *InstCombiner::visitOr(Binar
if (Value *V = matchSelectFromAndOr(D, B, C, A, Builder))
return replaceInstUsesWith(I, V);
}
-
- // ((A|B)&1)|(B&-2) -> (A&1) | B
- if (match(A, m_c_Or(m_Value(V1), m_Specific(B)))) {
- if (Instruction *Ret = FoldOrWithConstants(I, Op1, V1, B, C, Builder))
- return Ret;
- }
- // (B&-2)|((A|B)&1) -> (A&1) | B
- if (match(B, m_c_Or(m_Specific(A), m_Value(V1)))) {
- if (Instruction *Ret = FoldOrWithConstants(I, Op0, A, V1, D, Builder))
- return Ret;
- }
- // ((A^B)&1)|(B&-2) -> (A&1) ^ B
- if (match(A, m_c_Xor(m_Value(V1), m_Specific(B)))) {
- if (Instruction *Ret = FoldXorWithConstants(I, Op1, V1, B, C, Builder))
- return Ret;
- }
- // (B&-2)|((A^B)&1) -> (A&1) ^ B
- if (match(B, m_c_Xor(m_Specific(A), m_Value(V1)))) {
- if (Instruction *Ret = FoldXorWithConstants(I, Op0, A, V1, D, Builder))
- return Ret;
- }
}
// (A ^ B) | ((B ^ C) ^ A) -> (A ^ B) | C
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