From 521c9dc7d807c7716d69f86a902b47100e34d508 Mon Sep 17 00:00:00 2001 From: Philip Reames Date: Mon, 24 Nov 2014 23:44:28 +0000 Subject: [PATCH] Factor check for the assume intrinsic out of checks in computeKnownBitsFromAssume We were matching against the assume intrinsic in every check. Since we know that it must be an assume, this is just wasted work. Somewhat surprisingly, matching an intrinsic id is actually relatively expensive. It devolves to a string construction and comparison in Function::isIntrinsic. I originally spotted this because it showed up in a performance profile of my compiler. I've since discovered a separate issue which seems to be the actual root cause, but this is minor perf goodness regardless. I'm likely to follow up with another change to factor out the comparison matching. There's no need to match the compare instruction in every single one of the tests. Differential Revision: http://reviews.llvm.org/D6312 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222709 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Analysis/ValueTracking.cpp | 81 ++++++++++++++++------------------ 1 file changed, 39 insertions(+), 42 deletions(-) diff --git a/lib/Analysis/ValueTracking.cpp b/lib/Analysis/ValueTracking.cpp index e9bbf83fa96..ced5151582f 100644 --- a/lib/Analysis/ValueTracking.cpp +++ b/lib/Analysis/ValueTracking.cpp @@ -491,7 +491,17 @@ static void computeKnownBitsFromAssume(Value *V, APInt &KnownZero, if (Q.ExclInvs.count(I)) continue; - if (match(I, m_Intrinsic(m_Specific(V))) && + // Warning: This loop can end up being somewhat performance sensetive. + // We're running this loop for once for each value queried resulting in a + // runtime of ~O(#assumes * #values). + + assert(isa(I) && + dyn_cast(I)->getIntrinsicID() == Intrinsic::assume && + "must be an assume intrinsic"); + + Value *Arg = I->getArgOperand(0); + + if (Arg == V && isValidAssumeForContext(I, Q, DL)) { assert(BitWidth == 1 && "assume operand is not i1?"); KnownZero.clearAllBits(); @@ -507,16 +517,15 @@ static void computeKnownBitsFromAssume(Value *V, APInt &KnownZero, CmpInst::Predicate Pred; ConstantInt *C; // assume(v = a) - if (match(I, m_Intrinsic( - m_c_ICmp(Pred, m_V, m_Value(A)))) && + if (match(Arg, m_c_ICmp(Pred, m_V, m_Value(A))) && Pred == ICmpInst::ICMP_EQ && isValidAssumeForContext(I, Q, DL)) { APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0); computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I)); KnownZero |= RHSKnownZero; KnownOne |= RHSKnownOne; // assume(v & b = a) - } else if (match(I, m_Intrinsic( - m_c_ICmp(Pred, m_c_And(m_V, m_Value(B)), m_Value(A)))) && + } else if (match(Arg, m_c_ICmp(Pred, m_c_And(m_V, m_Value(B)), + m_Value(A))) && Pred == ICmpInst::ICMP_EQ && isValidAssumeForContext(I, Q, DL)) { APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0); computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I)); @@ -528,9 +537,8 @@ static void computeKnownBitsFromAssume(Value *V, APInt &KnownZero, KnownZero |= RHSKnownZero & MaskKnownOne; KnownOne |= RHSKnownOne & MaskKnownOne; // assume(~(v & b) = a) - } else if (match(I, m_Intrinsic( - m_c_ICmp(Pred, m_Not(m_c_And(m_V, m_Value(B))), - m_Value(A)))) && + } else if (match(Arg, m_c_ICmp(Pred, m_Not(m_c_And(m_V, m_Value(B))), + m_Value(A))) && Pred == ICmpInst::ICMP_EQ && isValidAssumeForContext(I, Q, DL)) { APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0); computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I)); @@ -542,8 +550,8 @@ static void computeKnownBitsFromAssume(Value *V, APInt &KnownZero, KnownZero |= RHSKnownOne & MaskKnownOne; KnownOne |= RHSKnownZero & MaskKnownOne; // assume(v | b = a) - } else if (match(I, m_Intrinsic( - m_c_ICmp(Pred, m_c_Or(m_V, m_Value(B)), m_Value(A)))) && + } else if (match(Arg, m_c_ICmp(Pred, m_c_Or(m_V, m_Value(B)), + m_Value(A))) && Pred == ICmpInst::ICMP_EQ && isValidAssumeForContext(I, Q, DL)) { APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0); computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I)); @@ -555,9 +563,8 @@ static void computeKnownBitsFromAssume(Value *V, APInt &KnownZero, KnownZero |= RHSKnownZero & BKnownZero; KnownOne |= RHSKnownOne & BKnownZero; // assume(~(v | b) = a) - } else if (match(I, m_Intrinsic( - m_c_ICmp(Pred, m_Not(m_c_Or(m_V, m_Value(B))), - m_Value(A)))) && + } else if (match(Arg, m_c_ICmp(Pred, m_Not(m_c_Or(m_V, m_Value(B))), + m_Value(A))) && Pred == ICmpInst::ICMP_EQ && isValidAssumeForContext(I, Q, DL)) { APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0); computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I)); @@ -569,8 +576,8 @@ static void computeKnownBitsFromAssume(Value *V, APInt &KnownZero, KnownZero |= RHSKnownOne & BKnownZero; KnownOne |= RHSKnownZero & BKnownZero; // assume(v ^ b = a) - } else if (match(I, m_Intrinsic( - m_c_ICmp(Pred, m_c_Xor(m_V, m_Value(B)), m_Value(A)))) && + } else if (match(Arg, m_c_ICmp(Pred, m_c_Xor(m_V, m_Value(B)), + m_Value(A))) && Pred == ICmpInst::ICMP_EQ && isValidAssumeForContext(I, Q, DL)) { APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0); computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I)); @@ -585,9 +592,8 @@ static void computeKnownBitsFromAssume(Value *V, APInt &KnownZero, KnownZero |= RHSKnownOne & BKnownOne; KnownOne |= RHSKnownZero & BKnownOne; // assume(~(v ^ b) = a) - } else if (match(I, m_Intrinsic( - m_c_ICmp(Pred, m_Not(m_c_Xor(m_V, m_Value(B))), - m_Value(A)))) && + } else if (match(Arg, m_c_ICmp(Pred, m_Not(m_c_Xor(m_V, m_Value(B))), + m_Value(A))) && Pred == ICmpInst::ICMP_EQ && isValidAssumeForContext(I, Q, DL)) { APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0); computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I)); @@ -602,9 +608,8 @@ static void computeKnownBitsFromAssume(Value *V, APInt &KnownZero, KnownZero |= RHSKnownZero & BKnownOne; KnownOne |= RHSKnownOne & BKnownOne; // assume(v << c = a) - } else if (match(I, m_Intrinsic( - m_c_ICmp(Pred, m_Shl(m_V, m_ConstantInt(C)), - m_Value(A)))) && + } else if (match(Arg, m_c_ICmp(Pred, m_Shl(m_V, m_ConstantInt(C)), + m_Value(A))) && Pred == ICmpInst::ICMP_EQ && isValidAssumeForContext(I, Q, DL)) { APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0); computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I)); @@ -613,9 +618,8 @@ static void computeKnownBitsFromAssume(Value *V, APInt &KnownZero, KnownZero |= RHSKnownZero.lshr(C->getZExtValue()); KnownOne |= RHSKnownOne.lshr(C->getZExtValue()); // assume(~(v << c) = a) - } else if (match(I, m_Intrinsic( - m_c_ICmp(Pred, m_Not(m_Shl(m_V, m_ConstantInt(C))), - m_Value(A)))) && + } else if (match(Arg, m_c_ICmp(Pred, m_Not(m_Shl(m_V, m_ConstantInt(C))), + m_Value(A))) && Pred == ICmpInst::ICMP_EQ && isValidAssumeForContext(I, Q, DL)) { APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0); computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I)); @@ -624,11 +628,11 @@ static void computeKnownBitsFromAssume(Value *V, APInt &KnownZero, KnownZero |= RHSKnownOne.lshr(C->getZExtValue()); KnownOne |= RHSKnownZero.lshr(C->getZExtValue()); // assume(v >> c = a) - } else if (match(I, m_Intrinsic( - m_c_ICmp(Pred, m_CombineOr(m_LShr(m_V, m_ConstantInt(C)), + } else if (match(Arg, + m_c_ICmp(Pred, m_CombineOr(m_LShr(m_V, m_ConstantInt(C)), m_AShr(m_V, m_ConstantInt(C))), - m_Value(A)))) && + m_Value(A))) && Pred == ICmpInst::ICMP_EQ && isValidAssumeForContext(I, Q, DL)) { APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0); computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I)); @@ -637,11 +641,10 @@ static void computeKnownBitsFromAssume(Value *V, APInt &KnownZero, KnownZero |= RHSKnownZero << C->getZExtValue(); KnownOne |= RHSKnownOne << C->getZExtValue(); // assume(~(v >> c) = a) - } else if (match(I, m_Intrinsic( - m_c_ICmp(Pred, m_Not(m_CombineOr( + } else if (match(Arg, m_c_ICmp(Pred, m_Not(m_CombineOr( m_LShr(m_V, m_ConstantInt(C)), m_AShr(m_V, m_ConstantInt(C)))), - m_Value(A)))) && + m_Value(A))) && Pred == ICmpInst::ICMP_EQ && isValidAssumeForContext(I, Q, DL)) { APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0); computeKnownBits(A, RHSKnownZero, RHSKnownOne, DL, Depth+1, Query(Q, I)); @@ -650,8 +653,7 @@ static void computeKnownBitsFromAssume(Value *V, APInt &KnownZero, KnownZero |= RHSKnownOne << C->getZExtValue(); KnownOne |= RHSKnownZero << C->getZExtValue(); // assume(v >=_s c) where c is non-negative - } else if (match(I, m_Intrinsic( - m_ICmp(Pred, m_V, m_Value(A)))) && + } else if (match(Arg, m_ICmp(Pred, m_V, m_Value(A))) && Pred == ICmpInst::ICMP_SGE && isValidAssumeForContext(I, Q, DL)) { APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0); @@ -662,8 +664,7 @@ static void computeKnownBitsFromAssume(Value *V, APInt &KnownZero, KnownZero |= APInt::getSignBit(BitWidth); } // assume(v >_s c) where c is at least -1. - } else if (match(I, m_Intrinsic( - m_ICmp(Pred, m_V, m_Value(A)))) && + } else if (match(Arg, m_ICmp(Pred, m_V, m_Value(A))) && Pred == ICmpInst::ICMP_SGT && isValidAssumeForContext(I, Q, DL)) { APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0); @@ -674,8 +675,7 @@ static void computeKnownBitsFromAssume(Value *V, APInt &KnownZero, KnownZero |= APInt::getSignBit(BitWidth); } // assume(v <=_s c) where c is negative - } else if (match(I, m_Intrinsic( - m_ICmp(Pred, m_V, m_Value(A)))) && + } else if (match(Arg, m_ICmp(Pred, m_V, m_Value(A))) && Pred == ICmpInst::ICMP_SLE && isValidAssumeForContext(I, Q, DL)) { APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0); @@ -686,8 +686,7 @@ static void computeKnownBitsFromAssume(Value *V, APInt &KnownZero, KnownOne |= APInt::getSignBit(BitWidth); } // assume(v <_s c) where c is non-positive - } else if (match(I, m_Intrinsic( - m_ICmp(Pred, m_V, m_Value(A)))) && + } else if (match(Arg, m_ICmp(Pred, m_V, m_Value(A))) && Pred == ICmpInst::ICMP_SLT && isValidAssumeForContext(I, Q, DL)) { APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0); @@ -698,8 +697,7 @@ static void computeKnownBitsFromAssume(Value *V, APInt &KnownZero, KnownOne |= APInt::getSignBit(BitWidth); } // assume(v <=_u c) - } else if (match(I, m_Intrinsic( - m_ICmp(Pred, m_V, m_Value(A)))) && + } else if (match(Arg, m_ICmp(Pred, m_V, m_Value(A))) && Pred == ICmpInst::ICMP_ULE && isValidAssumeForContext(I, Q, DL)) { APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0); @@ -709,8 +707,7 @@ static void computeKnownBitsFromAssume(Value *V, APInt &KnownZero, KnownZero |= APInt::getHighBitsSet(BitWidth, RHSKnownZero.countLeadingOnes()); // assume(v <_u c) - } else if (match(I, m_Intrinsic( - m_ICmp(Pred, m_V, m_Value(A)))) && + } else if (match(Arg, m_ICmp(Pred, m_V, m_Value(A))) && Pred == ICmpInst::ICMP_ULT && isValidAssumeForContext(I, Q, DL)) { APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0);