From 643d21a62c9e4d0f26e471f9a1d94878a5171c01 Mon Sep 17 00:00:00 2001 From: Sanjay Patel Date: Sun, 21 Aug 2016 17:10:07 +0000 Subject: [InstCombine] use m_APInt to allow icmp (shl X, Y), C folds for splat constant vectors, part 4 This concludes the fixes for icmp+shl in this series: https://reviews.llvm.org/rL279339 https://reviews.llvm.org/rL279398 https://reviews.llvm.org/rL279399 llvm-svn: 279401 --- .../Transforms/InstCombine/InstCombineCompares.cpp | 23 ++++++++++------------ 1 file changed, 10 insertions(+), 13 deletions(-) (limited to 'llvm/lib/Transforms') diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp index b36eadf6aad..c32821c73f8 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp @@ -2042,23 +2042,20 @@ Instruction *InstCombiner::foldICmpShlConstant(ICmpInst &Cmp, Instruction *Shl, And, Constant::getNullValue(And->getType())); } - // FIXME: This check restricts all folds under here to scalar types. - ConstantInt *RHS = dyn_cast(Cmp.getOperand(1)); - if (!RHS) - return nullptr; - - // Transform (icmp pred iM (shl iM %v, N), CI) - // -> (icmp pred i(M-N) (trunc %v iM to i(M-N)), (trunc (CI>>N)) - // Transform the shl to a trunc if (trunc (CI>>N)) has no loss and M-N. - // This enables to get rid of the shift in favor of a trunc which can be + // Transform (icmp pred iM (shl iM %v, N), C) + // -> (icmp pred i(M-N) (trunc %v iM to i(M-N)), (trunc (C>>N)) + // Transform the shl to a trunc if (trunc (C>>N)) has no loss and M-N. + // This enables us to get rid of the shift in favor of a trunc which can be // free on the target. It has the additional benefit of comparing to a // smaller constant, which will be target friendly. unsigned Amt = ShiftAmt->getLimitedValue(TypeBits - 1); if (Shl->hasOneUse() && Amt != 0 && C->countTrailingZeros() >= Amt) { - Type *NTy = IntegerType::get(Cmp.getContext(), TypeBits - Amt); - Constant *NCI = ConstantExpr::getTrunc( - ConstantExpr::getAShr(RHS, ConstantInt::get(RHS->getType(), Amt)), NTy); - return new ICmpInst(Pred, Builder->CreateTrunc(X, NTy), NCI); + Type *TruncTy = IntegerType::get(Cmp.getContext(), TypeBits - Amt); + if (X->getType()->isVectorTy()) + TruncTy = VectorType::get(TruncTy, X->getType()->getVectorNumElements()); + Constant *NewC = + ConstantInt::get(TruncTy, C->ashr(*ShiftAmt).trunc(TypeBits - Amt)); + return new ICmpInst(Pred, Builder->CreateTrunc(X, TruncTy), NewC); } return nullptr; -- cgit v1.2.3