1 //===-- SystemZTDC.cpp - Utilize Test Data Class instruction --------------===//
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //===----------------------------------------------------------------------===//
14 // 1: fcmp pred X, 0 -> tdc X, mask
15 // 2: fcmp pred X, +-inf -> tdc X, mask
16 // 3: fcmp pred X, +-minnorm -> tdc X, mask
17 // 4: tdc (fabs X), mask -> tdc X, newmask
18 // 5: icmp slt (bitcast float X to int), 0 -> tdc X, mask [ie. signbit]
19 // 6: icmp sgt (bitcast float X to int), -1 -> tdc X, mask
20 // 7: icmp ne/eq (call @llvm.s390.tdc.*(X, mask)) -> tdc X, mask/~mask
21 // 8: and i1 (tdc X, M1), (tdc X, M2) -> tdc X, (M1 & M2)
22 // 9: or i1 (tdc X, M1), (tdc X, M2) -> tdc X, (M1 | M2)
23 // 10: xor i1 (tdc X, M1), (tdc X, M2) -> tdc X, (M1 ^ M2)
25 // The pass works in 4 steps:
27 // 1. All fcmp and icmp instructions in a function are checked for a match
28 //    with rules 1-3 and 5-7.  Their TDC equivalents are stored in
32 //    mapped are mapped according to rules 8-10.  LogicOpsWorklist is used
39 // Instructions that match rules 1-3 are considered unworthy of conversion
41 // in the hopes of folding the result using rules 4 and 8-10 (likely removing
42 // the original comparison in the process).
44 //===----------------------------------------------------------------------===//
98   // Marks an instruction as converted - adds it to ConvertedInsts and adds
102     auto &M = *I->getFunction()->getParent();  in converted()
104     for (auto *U : I->users()) {  in converted()
106       if (LI && LI->getType() == Type::getInt1Ty(Ctx) &&  in converted()
107           (LI->getOpcode() == Instruction::And ||  in converted()
108            LI->getOpcode() == Instruction::Or ||  in converted()
109            LI->getOpcode() == Instruction::Xor)) {  in converted()
119 INITIALIZE_PASS(SystemZTDCPass, "systemz-tdc",
134   auto &Sem = Op0->getType()->getFltSemantics();  in convertFCmp()
140   if (Const->isZero()) {  in convertFCmp()
143   } else if (Const->isInfinity()) {  in convertFCmp()
145     WhichConst = Const->isNegative() ? 2 : 1;  in convertFCmp()
146   } else if (Const->isExactlyValue(Smallest)) {  in convertFCmp()
152   } else if (Const->isExactlyValue(NegSmallest)) {  in convertFCmp()
162   // Partial masks to use for EQ, GT, LT, UN comparisons, respectively.  in convertFCmp()
163   static const int Masks[][4] = {  in convertFCmp()  local
179     { // -inf  in convertFCmp()
197     { // -minnorm  in convertFCmp()
207   // Construct the mask as a combination of the partial masks.  in convertFCmp()
210     Mask |= Masks[WhichConst][0];  in convertFCmp()
212     Mask |= Masks[WhichConst][1];  in convertFCmp()
214     Mask |= Masks[WhichConst][2];  in convertFCmp()
216     Mask |= Masks[WhichConst][3];  in convertFCmp()
221     Function *F = CI->getCalledFunction();  in convertFCmp()
222     if (F && F->getIntrinsicID() == Intrinsic::fabs) {  in convertFCmp()
223       // Fold with fabs - adjust the mask appropriately.  in convertFCmp()
226       Op0 = CI->getArgOperand(0);  in convertFCmp()
245     if (!Cast->getSrcTy()->isFloatTy() &&  in convertICmp()
246         !Cast->getSrcTy()->isDoubleTy() &&  in convertICmp()
247         !Cast->getSrcTy()->isFP128Ty())  in convertICmp()
249     Value *V = Cast->getOperand(0);  in convertICmp()
251     if (Pred == CmpInst::ICMP_SLT && Const->isZero()) {  in convertICmp()
252       // icmp slt (bitcast X), 0 - set if sign bit true  in convertICmp()
254     } else if (Pred == CmpInst::ICMP_SGT && Const->isMinusOne()) {  in convertICmp()
255       // icmp sgt (bitcast X), -1 - set if sign bit false  in convertICmp()
264     // Check if this is a pre-existing call of our tdc intrinsic.  in convertICmp()
265     Function *F = CI->getCalledFunction();  in convertICmp()
266     if (!F || F->getIntrinsicID() != Intrinsic::s390_tdc)  in convertICmp()
268     if (!Const->isZero())  in convertICmp()
270     Value *V = CI->getArgOperand(0);  in convertICmp()
271     auto *MaskC = dyn_cast<ConstantInt>(CI->getArgOperand(1));  in convertICmp()
275     int Mask = MaskC->getZExtValue();  in convertICmp()
278       // icmp ne (call llvm.s390.tdc(...)), 0 -> simple TDC  in convertICmp()
280       // icmp eq (call llvm.s390.tdc(...)), 0 -> TDC with inverted mask  in convertICmp()
283       // An unknown comparison - ignore.  in convertICmp()
311       llvm_unreachable("Unknown op in convertLogicOp");  in convertLogicOp()
345     if (ConvertedInsts.count(dyn_cast<Instruction>(Op->getOperand(0))) &&  in runOnFunction()
346         ConvertedInsts.count(dyn_cast<Instruction>(Op->getOperand(1))) &&  in runOnFunction()
351   // Time to actually replace the instructions.  Do it in the reverse order  in runOnFunction()
364     if (!I->user_empty()) {  in runOnFunction()
370           Intrinsic::getDeclaration(&M, Intrinsic::s390_tdc, V->getType());  in runOnFunction()
375       I->replaceAllUsesWith(ICmp);  in runOnFunction()
378     I->eraseFromParent();  in runOnFunction()
385   // We've actually done something - now clear misc accumulated junk (fabs,  in runOnFunction()
388     if (I->user_empty())  in runOnFunction()
389       I->eraseFromParent();  in runOnFunction()