[llvm-commits] [llvm] r147777 - in /llvm/trunk: lib/Transforms/InstCombine/InstCombineAndOrXor.cpp test/Transforms/InstCombine/sign-test-and-or.ll
Eli Friedman
eli.friedman at gmail.com
Mon Jan 9 15:05:03 PST 2012
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?
-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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