-/// Convert the llvm.part.set.iX.iY.iZ intrinsic. This intrinsic takes
-/// four integer arguments (iAny %Value, iAny %Replacement, i32 %Low, i32 %High)
-/// The first two arguments can be any bit width. The result is the same width
-/// as %Value. The operation replaces bits between %Low and %High with the value
-/// in %Replacement. If %Replacement is not the same width, it is truncated or
-/// zero extended as appropriate to fit the bits being replaced. If %Low is
-/// greater than %High then the inverse set of bits are replaced.
-/// @brief Lowering of llvm.bit.part.set intrinsic.
-static Instruction *LowerPartSet(CallInst *CI) {
- // Make sure we're dealing with a part select intrinsic here
- Function *F = CI->getCalledFunction();
- const FunctionType *FT = F->getFunctionType();
- if (!F->isDeclaration() || !FT->getReturnType()->isInteger() ||
- FT->getNumParams() != 4 || !FT->getParamType(0)->isInteger() ||
- !FT->getParamType(1)->isInteger() || !FT->getParamType(2)->isInteger() ||
- !FT->getParamType(3)->isInteger())
- return CI;
-
- // Get the intrinsic implementation function by converting all the . to _
- // in the intrinsic's function name and then reconstructing the function
- // declaration.
- std::string Name(F->getName());
- for (unsigned i = 4; i < Name.length(); ++i)
- if (Name[i] == '.')
- Name[i] = '_';
- Module* M = F->getParent();
- F = cast<Function>(M->getOrInsertFunction(Name, FT));
- F->setLinkage(GlobalValue::WeakLinkage);
-
- // If we haven't defined the impl function yet, do so now
- if (F->isDeclaration()) {
- // Note: the following code is based on code generated by llvm2cpp with
- // the following input. This is just *one* example of a generated function.
- // The functions vary by bit width of result and first two arguments.
- // The generated code has been changed to deal with any bit width not just
- // the 32/64 bitwidths used in the above sample.
- //
- // define i64 @part_set(i64 %Val, i32 %Rep, i32 %Lo, i32 %Hi) {
- // entry:
- // %is_forward = icmp ult i32 %Lo, %Hi
- // %Lo.pn = select i1 %is_forward, i32 %Hi, i32 %Lo
- // %Hi.pn = select i1 %is_forward, i32 %Lo, i32 %Hi
- // %iftmp.16.0 = sub i32 %Lo.pn, %Hi.pn
- // icmp ult i32 %iftmp.16.0, 32
- // br i1 %1, label %cond_true11, label %cond_next19
- // cond_true11:
- // %tmp13 = sub i32 32, %iftmp.16.0
- // %tmp14 = lshr i32 -1, %tmp13
- // %tmp16 = and i32 %tmp14, %Rep
- // br label %cond_next19
- // cond_next19:
- // %iftmp.17.0 = phi i32 [ %tmp16, %cond_true11 ], [ %Rep, %entry ]
- // %tmp2021 = zext i32 %iftmp.17.0 to i64
- // icmp ugt i32 %Lo, %Hi
- // br i1 %2, label %cond_next60, label %cond_true24
- // cond_true24:
- // %tmp25.cast = zext i32 %Hi to i64
- // %tmp26 = lshr i64 -1, %tmp25.cast
- // %tmp27.cast = zext i32 %Lo to i64
- // %tmp28 = shl i64 %tmp26, %tmp27.cast
- // %tmp28not = xor i64 %tmp28, -1
- // %tmp31 = shl i64 %tmp2021, %tmp27.cast
- // %tmp34 = and i64 %tmp28not, %Val
- // %Val_addr.064 = or i64 %tmp31, %tmp34
- // ret i64 %Val_addr.064
- // cond_next60:
- // %tmp39.cast = zext i32 %Lo to i64
- // %tmp40 = shl i64 -1, %tmp39.cast
- // %tmp41.cast = zext i32 %Hi to i64
- // %tmp42 = shl i64 -1, %tmp41.cast
- // %tmp45.demorgan = or i64 %tmp42, %tmp40
- // %tmp45 = xor i64 %tmp45.demorgan, -1
- // %tmp47 = and i64 %tmp45, %Val
- // %tmp50 = shl i64 %tmp2021, %tmp39.cast
- // %tmp52 = sub i32 32, %Hi
- // %tmp52.cast = zext i32 %tmp52 to i64
- // %tmp54 = lshr i64 %tmp2021, %tmp52.cast
- // %tmp57 = or i64 %tmp50, %tmp47
- // %Val_addr.0 = or i64 %tmp57, %tmp54
- // ret i64 %Val_addr.0
- // }
-
- // Get the arguments for the function.
- Function::arg_iterator args = F->arg_begin();
- Value* Val = args++; Val->setName("Val");
- Value* Rep = args++; Rep->setName("Rep");
- Value* Lo = args++; Lo->setName("Lo");
- Value* Hi = args++; Hi->setName("Hi");
-
- // Get some types we need
- const IntegerType* ValTy = cast<IntegerType>(Val->getType());
- const IntegerType* RepTy = cast<IntegerType>(Rep->getType());
- uint32_t ValBits = ValTy->getBitWidth();
- uint32_t RepBits = RepTy->getBitWidth();
-
- // Constant Definitions
- ConstantInt* RepBitWidth = ConstantInt::get(Type::Int32Ty, RepBits);
- ConstantInt* RepMask = ConstantInt::getAllOnesValue(RepTy);
- ConstantInt* ValMask = ConstantInt::getAllOnesValue(ValTy);
-
- BasicBlock* entry = new BasicBlock("entry",F,0);
- BasicBlock* large = new BasicBlock("large",F,0);
- BasicBlock* small = new BasicBlock("small",F,0);
- BasicBlock* forward = new BasicBlock("forward",F,0);
- BasicBlock* reverse = new BasicBlock("reverse",F,0);
-
- // Block entry (entry)
- // First, get the number of bits that we're placing as an i32
- ICmpInst* is_forward =
- new ICmpInst(ICmpInst::ICMP_ULT, Lo, Hi, "", entry);
- SelectInst* Lo_pn = new SelectInst(is_forward, Hi, Lo, "", entry);
- SelectInst* Hi_pn = new SelectInst(is_forward, Lo, Hi, "", entry);
- BinaryOperator* NumBits = BinaryOperator::createSub(Lo_pn, Hi_pn, "",entry);
- // Now, convert Lo and Hi to ValTy bit width
- if (ValBits > 32) {
- Hi = new ZExtInst(Hi, ValTy, "", entry);
- Lo = new ZExtInst(Lo, ValTy, "", entry);
- } else if (ValBits < 32) {
- Hi = new TruncInst(Hi, ValTy, "", entry);
- Lo = new TruncInst(Lo, ValTy, "", entry);
- }
- // Determine if the replacement bits are larger than the number of bits we
- // are replacing and deal with it.
- ICmpInst* is_large =
- new ICmpInst(ICmpInst::ICMP_ULT, NumBits, RepBitWidth, "", entry);
- new BranchInst(large, small, is_large, entry);
-
- // Block "large"
- BinaryOperator* MaskBits =
- BinaryOperator::createSub(RepBitWidth, NumBits, "", large);
- BinaryOperator* Mask1 =
- BinaryOperator::createLShr(RepMask, MaskBits, "", large);
- BinaryOperator* Rep2 = BinaryOperator::createAnd(Mask1, Rep, "", large);
- new BranchInst(small, large);
-
- // Block "small"
- PHINode* Rep3 = new PHINode(RepTy, "", small);
- Rep3->reserveOperandSpace(2);
- Rep3->addIncoming(Rep2, large);
- Rep3->addIncoming(Rep, entry);
- Value* Rep4 = Rep3;
- if (ValBits > RepBits)
- Rep4 = new ZExtInst(Rep3, ValTy, "", small);
- else if (ValBits < RepBits)
- Rep4 = new TruncInst(Rep3, ValTy, "", small);
- ICmpInst* is_reverse =
- new ICmpInst(ICmpInst::ICMP_UGT, Lo, Hi, "", small);
- new BranchInst(reverse, forward, is_reverse, small);
-
- // Block "forward"
- Value* t1 = BinaryOperator::createLShr(ValMask, Hi, "", forward);
- Value* t2 = BinaryOperator::createShl(t1, Lo, "", forward);
- Value* nott2 = BinaryOperator::createXor(t2, ValMask, "", forward);
- Value* t3 = BinaryOperator::createShl(Rep4, Lo, "", forward);
- Value* t4 = BinaryOperator::createAnd(nott2, Val, "", forward);
- Value* FRslt = BinaryOperator::createOr(t3, t4, "", forward);
- new ReturnInst(FRslt, forward);
-
- // Block "reverse"
- Value* t5 = BinaryOperator::createShl(ValMask, Lo, "", reverse);
- Value* t6 = BinaryOperator::createShl(ValMask, Hi, "", reverse);
- Value* t7 = BinaryOperator::createOr(t6, t5, "", reverse);
- Value* t8 = BinaryOperator::createXor(t7, ValMask, "", reverse);
- Value* t9 = BinaryOperator::createAnd(t8, Val, "", reverse);
- Value* t10 = BinaryOperator::createShl(Rep4, Lo, "", reverse);
- if (RepBits < ValBits)
- RepBitWidth =
- cast<ConstantInt>(ConstantExpr::getZExt(RepBitWidth, ValTy));
- else if (RepBits > ValBits)
- RepBitWidth =
- cast<ConstantInt>(ConstantExpr::getTrunc(RepBitWidth, ValTy));
- Value* t11 = BinaryOperator::createSub(RepBitWidth, Hi, "", reverse);
- Value* t13 = BinaryOperator::createLShr(Rep4, t11, "",reverse);
- Value* t14 = BinaryOperator::createOr(t10, t9, "", reverse);
- Value* RRslt = BinaryOperator::createOr(t14, t13, "", reverse);
- new ReturnInst(RRslt, reverse);
- }
-
- // Return a call to the implementation function
- Value *Args[3];
- Args[0] = CI->getOperand(1);
- Args[1] = CI->getOperand(2);
- Args[2] = CI->getOperand(3);
- Args[3] = CI->getOperand(4);
- return new CallInst(F, Args, 4, CI->getName(), CI);