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[InstCombine] Make (X|C1)^C2 -> X^(C1^C2) iff X&~C1 == 0 work for splat vectors 

This also corrects the description to match what was actually implemented. The old comment said X^(C1|C2), but it implemented X^((C1|C2)&~(C1&C2)). I believe ((C1|C2)&~(C1&C2)) is equivalent to (C1^C2).

Differential Revision: https://reviews.llvm.org/D36505

llvm-svn: 310658
This commit is contained in:
Craig Topper 2017-08-10 20:35:34 +00:00
parent 699ae0c173
commit 9a6110b2d3
3 changed files with 38 additions and 33 deletions
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41
llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
View File

@ -2365,53 +2365,48 @@ Instruction *InstCombiner::visitXor(BinaryOperator &I) {
{
const APInt *RHSC;
if (match(Op1, m_APInt(RHSC))) {
Value *V;
Value *X;
const APInt *C;
if (match(Op0, m_Sub(m_APInt(C), m_Value(V)))) {
if (match(Op0, m_Sub(m_APInt(C), m_Value(X)))) {
// ~(c-X) == X-c-1 == X+(-c-1)
if (RHSC->isAllOnesValue()) {
Constant *NewC = ConstantInt::get(I.getType(), -(*C) - 1);
return BinaryOperator::CreateAdd(V, NewC);
return BinaryOperator::CreateAdd(X, NewC);
}
if (RHSC->isSignMask()) {
// (C - X) ^ signmask -> (C + signmask - X)
Constant *NewC = ConstantInt::get(I.getType(), *C + *RHSC);
return BinaryOperator::CreateSub(NewC, V);
return BinaryOperator::CreateSub(NewC, X);
}
} else if (match(Op0, m_Add(m_Value(V), m_APInt(C)))) {
} else if (match(Op0, m_Add(m_Value(X), m_APInt(C)))) {
// ~(X-c) --> (-c-1)-X
if (RHSC->isAllOnesValue()) {
Constant *NewC = ConstantInt::get(I.getType(), -(*C) - 1);
return BinaryOperator::CreateSub(NewC, V);
return BinaryOperator::CreateSub(NewC, X);
}
if (RHSC->isSignMask()) {
// (X + C) ^ signmask -> (X + C + signmask)
Constant *NewC = ConstantInt::get(I.getType(), *C + *RHSC);
return BinaryOperator::CreateAdd(V, NewC);
return BinaryOperator::CreateAdd(X, NewC);
}
}
// (X|C1)^C2 -> X^(C1^C2) iff X&~C1 == 0
if (match(Op0, m_Or(m_Value(X), m_APInt(C))) &&
MaskedValueIsZero(X, *C, 0, &I)) {
Constant *NewC = ConstantInt::get(I.getType(), *C ^ *RHSC);
Worklist.Add(cast<Instruction>(Op0));
I.setOperand(0, X);
I.setOperand(1, NewC);
return &I;
}
}
}
if (ConstantInt *RHSC = dyn_cast<ConstantInt>(Op1)) {
if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0)) {
if (ConstantInt *Op0CI = dyn_cast<ConstantInt>(Op0I->getOperand(1))) {
if (Op0I->getOpcode() == Instruction::Or) {
// (X|C1)^C2 -> X^(C1|C2) iff X&~C1 == 0
if (MaskedValueIsZero(Op0I->getOperand(0), Op0CI->getValue(),
0, &I)) {
Constant *NewRHS = ConstantExpr::getOr(Op0CI, RHSC);
// Anything in both C1 and C2 is known to be zero, remove it from
// NewRHS.
Constant *CommonBits = ConstantExpr::getAnd(Op0CI, RHSC);
NewRHS = ConstantExpr::getAnd(NewRHS,
ConstantExpr::getNot(CommonBits));
Worklist.Add(Op0I);
I.setOperand(0, Op0I->getOperand(0));
I.setOperand(1, NewRHS);
return &I;
}
} else if (Op0I->getOpcode() == Instruction::LShr) {
if (Op0I->getOpcode() == Instruction::LShr) {
// ((X^C1) >> C2) ^ C3 -> (X>>C2) ^ ((C1>>C2)^C3)
// E1 = "X ^ C1"
BinaryOperator *E1;

13
llvm/test/Transforms/InstCombine/or.ll
View File

@ -143,6 +143,19 @@ define i16 @test23(i16 %A) {
ret i16 %D
}
define <2 x i16> @test23vec(<2 x i16> %A) {
; CHECK-LABEL: @test23vec(
; CHECK-NEXT: [[B:%.*]] = lshr <2 x i16> [[A:%.*]], <i16 1, i16 1>
; CHECK-NEXT: [[D:%.*]] = xor <2 x i16> [[B]], <i16 -24575, i16 -24575>
; CHECK-NEXT: ret <2 x i16> [[D]]
;
%B = lshr <2 x i16> %A, <i16 1, i16 1>
;; fold or into xor
%C = or <2 x i16> %B, <i16 -32768, i16 -32768>
%D = xor <2 x i16> %C, <i16 8193, i16 8193>
ret <2 x i16> %D
}
; PR1738
define i1 @test24(double %X, double %Y) {
; CHECK-LABEL: @test24(

17
llvm/test/Transforms/InstCombine/select-with-bitwise-ops.ll
View File

@ -273,9 +273,8 @@ define <2 x i32> @test65vec(<2 x i64> %x) {
; CHECK-NEXT: [[TMP1:%.*]] = lshr <2 x i64> [[X:%.*]], <i64 3, i64 3>
; CHECK-NEXT: [[TMP2:%.*]] = trunc <2 x i64> [[TMP1]] to <2 x i32>
; CHECK-NEXT: [[TMP3:%.*]] = and <2 x i32> [[TMP2]], <i32 2, i32 2>
; CHECK-NEXT: [[TMP4:%.*]] = or <2 x i32> [[TMP3]], <i32 40, i32 40>
; CHECK-NEXT: [[TMP5:%.*]] = xor <2 x i32> [[TMP4]], <i32 2, i32 2>
; CHECK-NEXT: ret <2 x i32> [[TMP5]]
; CHECK-NEXT: [[TMP4:%.*]] = xor <2 x i32> [[TMP3]], <i32 42, i32 42>
; CHECK-NEXT: ret <2 x i32> [[TMP4]]
;
%1 = and <2 x i64> %x, <i64 16, i64 16>
%2 = icmp ne <2 x i64> %1, zeroinitializer
@ -302,9 +301,8 @@ define <2 x i32> @test66vec(<2 x i64> %x) {
; CHECK-NEXT: [[TMP1:%.*]] = lshr <2 x i64> [[X:%.*]], <i64 31, i64 31>
; CHECK-NEXT: [[TMP2:%.*]] = trunc <2 x i64> [[TMP1]] to <2 x i32>
; CHECK-NEXT: [[TMP3:%.*]] = and <2 x i32> [[TMP2]], <i32 2, i32 2>
; CHECK-NEXT: [[TMP4:%.*]] = or <2 x i32> [[TMP3]], <i32 40, i32 40>
; CHECK-NEXT: [[TMP5:%.*]] = xor <2 x i32> [[TMP4]], <i32 2, i32 2>
; CHECK-NEXT: ret <2 x i32> [[TMP5]]
; CHECK-NEXT: [[TMP4:%.*]] = xor <2 x i32> [[TMP3]], <i32 42, i32 42>
; CHECK-NEXT: ret <2 x i32> [[TMP4]]
;
%1 = and <2 x i64> %x, <i64 4294967296, i64 4294967296>
%2 = icmp ne <2 x i64> %1, zeroinitializer
@ -344,10 +342,9 @@ define <2 x i32> @test67vec(<2 x i16> %x) {
; CHECK-LABEL: @test67vec(
; CHECK-NEXT: [[TMP1:%.*]] = lshr <2 x i16> [[X:%.*]], <i16 1, i16 1>
; CHECK-NEXT: [[TMP2:%.*]] = and <2 x i16> [[TMP1]], <i16 2, i16 2>
; CHECK-NEXT: [[TMP3:%.*]] = or <2 x i16> [[TMP2]], <i16 40, i16 40>
; CHECK-NEXT: [[TMP4:%.*]] = xor <2 x i16> [[TMP3]], <i16 2, i16 2>
; CHECK-NEXT: [[TMP5:%.*]] = zext <2 x i16> [[TMP4]] to <2 x i32>
; CHECK-NEXT: ret <2 x i32> [[TMP5]]
; CHECK-NEXT: [[TMP3:%.*]] = xor <2 x i16> [[TMP2]], <i16 42, i16 42>
; CHECK-NEXT: [[TMP4:%.*]] = zext <2 x i16> [[TMP3]] to <2 x i32>
; CHECK-NEXT: ret <2 x i32> [[TMP4]]
;
%1 = and <2 x i16> %x, <i16 4, i16 4>
%2 = icmp ne <2 x i16> %1, zeroinitializer