[llvm-commits] [llvm] r147777 - in /llvm/trunk: lib/Transforms/InstCombine/InstCombineAndOrXor.cpp test/Transforms/InstCombine/sign-test-and-or.ll
Benjamin Kramer
benny.kra at googlemail.com
Tue Jan 10 02:54:56 PST 2012
On 10.01.2012, at 00:05, Eli Friedman wrote:
> On Mon, Jan 9, 2012 at 9:23 AM, Benjamin Kramer
> <benny.kra at googlemail.com> wrote:
>> Author: d0k
>> Date: Mon Jan 9 11:23:27 2012
>> New Revision: 147777
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=147777&view=rev
>> Log:
>> InstCombine: Teach foldLogOpOfMaskedICmpsHelper that sign bit tests are bit tests.
>>
>> This subsumes several other transforms while enabling us to catch more cases.
>
> This commit appears to be causing failures on
> http://lab.llvm.org:8011/builders/llvm-arm-linux/builds/419 . Any
> ideas?
r147779, the bot cycled back to green already.
> -Eli
>
>> Modified:
>> llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
>> llvm/trunk/test/Transforms/InstCombine/sign-test-and-or.ll
>>
>> Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp?rev=147777&r1=147776&r2=147777&view=diff
>> ==============================================================================
>> --- llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp (original)
>> +++ llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp Mon Jan 9 11:23:27 2012
>> @@ -496,6 +496,38 @@
>> return result;
>> }
>>
>> +/// decomposeBitTestICmp - Decompose an icmp into the form ((X & Y) pred Z)
>> +/// if possible. The returned predicate is either == or !=. Returns false if
>> +/// decomposition fails.
>> +static bool decomposeBitTestICmp(const ICmpInst *I, ICmpInst::Predicate &Pred,
>> + Value *&X, Value *&Y, Value *&Z) {
>> + // X < 0 is equivalent to (X & SignBit) != 0.
>> + if (I->getPredicate() == ICmpInst::ICMP_SLT)
>> + if (ConstantInt *C = dyn_cast<ConstantInt>(I->getOperand(1)))
>> + if (C->isZero()) {
>> + X = I->getOperand(0);
>> + Y = ConstantInt::get(I->getContext(),
>> + APInt::getSignBit(C->getBitWidth()));
>> + Pred = ICmpInst::ICMP_NE;
>> + Z = C;
>> + return true;
>> + }
>> +
>> + // X > -1 is equivalent to (X & SignBit) == 0.
>> + if (I->getPredicate() == ICmpInst::ICMP_SGT)
>> + if (ConstantInt *C = dyn_cast<ConstantInt>(I->getOperand(1)))
>> + if (C->isAllOnesValue()) {
>> + X = I->getOperand(0);
>> + Y = ConstantInt::get(I->getContext(),
>> + APInt::getSignBit(C->getBitWidth()));
>> + Pred = ICmpInst::ICMP_EQ;
>> + Z = ConstantInt::getNullValue(C->getType());
>> + return true;
>> + }
>> +
>> + return false;
>> +}
>> +
>> /// foldLogOpOfMaskedICmpsHelper:
>> /// handle (icmp(A & B) ==/!= C) &/| (icmp(A & D) ==/!= E)
>> /// return the set of pattern classes (from MaskedICmpType)
>> @@ -503,10 +535,9 @@
>> static unsigned foldLogOpOfMaskedICmpsHelper(Value*& A,
>> Value*& B, Value*& C,
>> Value*& D, Value*& E,
>> - ICmpInst *LHS, ICmpInst *RHS) {
>> - ICmpInst::Predicate LHSCC = LHS->getPredicate(), RHSCC = RHS->getPredicate();
>> - if (LHSCC != ICmpInst::ICMP_EQ && LHSCC != ICmpInst::ICMP_NE) return 0;
>> - if (RHSCC != ICmpInst::ICMP_EQ && RHSCC != ICmpInst::ICMP_NE) return 0;
>> + ICmpInst *LHS, ICmpInst *RHS,
>> + ICmpInst::Predicate &LHSCC,
>> + ICmpInst::Predicate &RHSCC) {
>> if (LHS->getOperand(0)->getType() != RHS->getOperand(0)->getType()) return 0;
>> // vectors are not (yet?) supported
>> if (LHS->getOperand(0)->getType()->isVectorTy()) return 0;
>> @@ -520,40 +551,60 @@
>> Value *L1 = LHS->getOperand(0);
>> Value *L2 = LHS->getOperand(1);
>> Value *L11,*L12,*L21,*L22;
>> - if (match(L1, m_And(m_Value(L11), m_Value(L12)))) {
>> - if (!match(L2, m_And(m_Value(L21), m_Value(L22))))
>> + // Check whether the icmp can be decomposed into a bit test.
>> + if (decomposeBitTestICmp(LHS, LHSCC, L11, L12, L2)) {
>> + L21 = L22 = L1 = 0;
>> + } else {
>> + // Look for ANDs in the LHS icmp.
>> + if (match(L1, m_And(m_Value(L11), m_Value(L12)))) {
>> + if (!match(L2, m_And(m_Value(L21), m_Value(L22))))
>> + L21 = L22 = 0;
>> + } else {
>> + if (!match(L2, m_And(m_Value(L11), m_Value(L12))))
>> + return 0;
>> + std::swap(L1, L2);
>> L21 = L22 = 0;
>> - }
>> - else {
>> - if (!match(L2, m_And(m_Value(L11), m_Value(L12))))
>> - return 0;
>> - std::swap(L1, L2);
>> - L21 = L22 = 0;
>> + }
>> }
>>
>> + // Bail if LHS was a icmp that can't be decomposed into an equality.
>> + if (!ICmpInst::isEquality(LHSCC))
>> + return 0;
>> +
>> Value *R1 = RHS->getOperand(0);
>> Value *R2 = RHS->getOperand(1);
>> Value *R11,*R12;
>> bool ok = false;
>> - if (match(R1, m_And(m_Value(R11), m_Value(R12)))) {
>> - if (R11 != 0 && (R11 == L11 || R11 == L12 || R11 == L21 || R11 == L22)) {
>> - A = R11; D = R12; E = R2; ok = true;
>> + if (decomposeBitTestICmp(RHS, RHSCC, R11, R12, R2)) {
>> + if (R11 == L11 || R11 == L12 || R11 == L21 || R11 == L22) {
>> + A = R11; D = R12;
>> + } else if (R12 == L11 || R12 == L12 || R12 == L21 || R12 == L22) {
>> + A = R12; D = R11;
>> + } else {
>> + return 0;
>> }
>> - else
>> - if (R12 != 0 && (R12 == L11 || R12 == L12 || R12 == L21 || R12 == L22)) {
>> + E = R2; R1 = 0; ok = true;
>> + } else if (match(R1, m_And(m_Value(R11), m_Value(R12)))) {
>> + if (R11 == L11 || R11 == L12 || R11 == L21 || R11 == L22) {
>> + A = R11; D = R12; E = R2; ok = true;
>> + } else if (R12 == L11 || R12 == L12 || R12 == L21 || R12 == L22) {
>> A = R12; D = R11; E = R2; ok = true;
>> }
>> }
>> +
>> + // Bail if RHS was a icmp that can't be decomposed into an equality.
>> + if (!ICmpInst::isEquality(RHSCC))
>> + return 0;
>> +
>> + // Look for ANDs in on the right side of the RHS icmp.
>> if (!ok && match(R2, m_And(m_Value(R11), m_Value(R12)))) {
>> - if (R11 != 0 && (R11 == L11 || R11 == L12 || R11 == L21 || R11 == L22)) {
>> - A = R11; D = R12; E = R1; ok = true;
>> - }
>> - else
>> - if (R12 != 0 && (R12 == L11 || R12 == L12 || R12 == L21 || R12 == L22)) {
>> + if (R11 == L11 || R11 == L12 || R11 == L21 || R11 == L22) {
>> + A = R11; D = R12; E = R1; ok = true;
>> + } else if (R12 == L11 || R12 == L12 || R12 == L21 || R12 == L22) {
>> A = R12; D = R11; E = R1; ok = true;
>> - }
>> - else
>> + } else {
>> return 0;
>> + }
>> }
>> if (!ok)
>> return 0;
>> @@ -582,7 +633,11 @@
>> ICmpInst::Predicate NEWCC,
>> llvm::InstCombiner::BuilderTy* Builder) {
>> Value *A = 0, *B = 0, *C = 0, *D = 0, *E = 0;
>> - unsigned mask = foldLogOpOfMaskedICmpsHelper(A, B, C, D, E, LHS, RHS);
>> + ICmpInst::Predicate LHSCC = LHS->getPredicate(), RHSCC = RHS->getPredicate();
>> + unsigned mask = foldLogOpOfMaskedICmpsHelper(A, B, C, D, E, LHS, RHS,
>> + LHSCC, RHSCC);
>> + assert(ICmpInst::isEquality(LHSCC) && ICmpInst::isEquality(RHSCC) &&
>> + "foldLogOpOfMaskedICmpsHelper must return an equality predicate.");
>> if (mask == 0) return 0;
>>
>> if (NEWCC == ICmpInst::ICMP_NE)
>> @@ -631,11 +686,11 @@
>>
>> ConstantInt *CCst = dyn_cast<ConstantInt>(C);
>> if (CCst == 0) return 0;
>> - if (LHS->getPredicate() != NEWCC)
>> + if (LHSCC != NEWCC)
>> CCst = dyn_cast<ConstantInt>( ConstantExpr::getXor(BCst, CCst) );
>> ConstantInt *ECst = dyn_cast<ConstantInt>(E);
>> if (ECst == 0) return 0;
>> - if (RHS->getPredicate() != NEWCC)
>> + if (RHSCC != NEWCC)
>> ECst = dyn_cast<ConstantInt>( ConstantExpr::getXor(DCst, ECst) );
>> ConstantInt* MCst = dyn_cast<ConstantInt>(
>> ConstantExpr::getAnd(ConstantExpr::getAnd(BCst, DCst),
>> @@ -694,18 +749,6 @@
>> Value *NewOr = Builder->CreateOr(Val, Val2);
>> return Builder->CreateICmp(LHSCC, NewOr, LHSCst);
>> }
>> -
>> - // (icmp slt A, 0) & (icmp slt B, 0) --> (icmp slt (A&B), 0)
>> - if (LHSCC == ICmpInst::ICMP_SLT && LHSCst->isZero()) {
>> - Value *NewAnd = Builder->CreateAnd(Val, Val2);
>> - return Builder->CreateICmp(LHSCC, NewAnd, LHSCst);
>> - }
>> -
>> - // (icmp sgt A, -1) & (icmp sgt B, -1) --> (icmp sgt (A|B), -1)
>> - if (LHSCC == ICmpInst::ICMP_SGT && LHSCst->isAllOnesValue()) {
>> - Value *NewOr = Builder->CreateOr(Val, Val2);
>> - return Builder->CreateICmp(LHSCC, NewOr, LHSCst);
>> - }
>> }
>>
>> // (trunc x) == C1 & (and x, CA) == C2 -> (and x, CA|CMAX) == C1|C2
>> @@ -744,21 +787,6 @@
>> }
>> }
>>
>> - // (X & C) == 0 & X > -1 -> (X & (C | SignBit)) == 0
>> - if ((LHSCC == ICmpInst::ICMP_EQ && LHSCst->isZero() &&
>> - RHSCC == ICmpInst::ICMP_SGT && RHSCst->isAllOnesValue()) ||
>> - (RHSCC == ICmpInst::ICMP_EQ && RHSCst->isZero() &&
>> - LHSCC == ICmpInst::ICMP_SGT && LHSCst->isAllOnesValue())) {
>> - ICmpInst *I = LHSCC == ICmpInst::ICMP_EQ ? LHS : RHS;
>> - Value *X; ConstantInt *C;
>> - if (I->hasOneUse() &&
>> - match(I->getOperand(0), m_OneUse(m_And(m_Value(X), m_ConstantInt(C))))){
>> - APInt New = C->getValue() | APInt::getSignBit(C->getBitWidth());
>> - return Builder->CreateICmpEQ(Builder->CreateAnd(X, Builder->getInt(New)),
>> - I->getOperand(1));
>> - }
>> - }
>> -
>> // From here on, we only handle:
>> // (icmp1 A, C1) & (icmp2 A, C2) --> something simpler.
>> if (Val != Val2) return 0;
>> @@ -1443,33 +1471,6 @@
>> Value *NewOr = Builder->CreateOr(Val, Val2);
>> return Builder->CreateICmp(LHSCC, NewOr, LHSCst);
>> }
>> -
>> - // (icmp slt A, 0) | (icmp slt B, 0) --> (icmp slt (A|B), 0)
>> - if (LHSCC == ICmpInst::ICMP_SLT && LHSCst->isZero()) {
>> - Value *NewOr = Builder->CreateOr(Val, Val2);
>> - return Builder->CreateICmp(LHSCC, NewOr, LHSCst);
>> - }
>> -
>> - // (icmp sgt A, -1) | (icmp sgt B, -1) --> (icmp sgt (A&B), -1)
>> - if (LHSCC == ICmpInst::ICMP_SGT && LHSCst->isAllOnesValue()) {
>> - Value *NewAnd = Builder->CreateAnd(Val, Val2);
>> - return Builder->CreateICmp(LHSCC, NewAnd, LHSCst);
>> - }
>> - }
>> -
>> - // (X & C) != 0 | X < 0 -> (X & (C | SignBit)) != 0
>> - if ((LHSCC == ICmpInst::ICMP_NE && LHSCst->isZero() &&
>> - RHSCC == ICmpInst::ICMP_SLT && RHSCst->isZero()) ||
>> - (RHSCC == ICmpInst::ICMP_NE && RHSCst->isZero() &&
>> - LHSCC == ICmpInst::ICMP_SLT && LHSCst->isZero())) {
>> - ICmpInst *I = LHSCC == ICmpInst::ICMP_NE ? LHS : RHS;
>> - Value *X; ConstantInt *C;
>> - if (I->hasOneUse() &&
>> - match(I->getOperand(0), m_OneUse(m_And(m_Value(X), m_ConstantInt(C))))){
>> - APInt New = C->getValue() | APInt::getSignBit(C->getBitWidth());
>> - return Builder->CreateICmpNE(Builder->CreateAnd(X, Builder->getInt(New)),
>> - I->getOperand(1));
>> - }
>> }
>>
>> // (icmp ult (X + CA), C1) | (icmp eq X, C2) -> (icmp ule (X + CA), C1)
>>
>> Modified: llvm/trunk/test/Transforms/InstCombine/sign-test-and-or.ll
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/sign-test-and-or.ll?rev=147777&r1=147776&r2=147777&view=diff
>> ==============================================================================
>> --- llvm/trunk/test/Transforms/InstCombine/sign-test-and-or.ll (original)
>> +++ llvm/trunk/test/Transforms/InstCombine/sign-test-and-or.ll Mon Jan 9 11:23:27 2012
>> @@ -157,3 +157,23 @@
>> if.end:
>> ret void
>> }
>> +
>> +define void @test9(i32 %a) nounwind {
>> + %1 = and i32 %a, 1073741824
>> + %2 = icmp ne i32 %1, 0
>> + %3 = icmp sgt i32 %a, -1
>> + %or.cond = and i1 %2, %3
>> + br i1 %or.cond, label %if.then, label %if.end
>> +
>> +; CHECK: @test9
>> +; CHECK-NEXT: %1 = and i32 %a, -1073741824
>> +; CHECK-NEXT: %2 = icmp eq i32 %1, 1073741824
>> +; CHECK-NEXT: br i1 %2, label %if.then, label %if.end
>> +
>> +if.then:
>> + tail call void @foo() nounwind
>> + ret void
>> +
>> +if.end:
>> + ret void
>> +}
>>
>>
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