1 //===-- IntrinsicLowering.cpp - Intrinsic Lowering default implementation -===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file implements the IntrinsicLowering class.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "llvm/CodeGen/IntrinsicLowering.h"
15 #include "llvm/ADT/SmallVector.h"
16 #include "llvm/IR/CallSite.h"
17 #include "llvm/IR/Constants.h"
18 #include "llvm/IR/DataLayout.h"
19 #include "llvm/IR/DerivedTypes.h"
20 #include "llvm/IR/IRBuilder.h"
21 #include "llvm/IR/Module.h"
22 #include "llvm/IR/Type.h"
23 #include "llvm/Support/ErrorHandling.h"
24 #include "llvm/Support/raw_ostream.h"
25 using namespace llvm;
26 
27 template <class ArgIt>
28 static void EnsureFunctionExists(Module &M, const char *Name,
29                                  ArgIt ArgBegin, ArgIt ArgEnd,
30                                  Type *RetTy) {
31   // Insert a correctly-typed definition now.
32   std::vector<Type *> ParamTys;
33   for (ArgIt I = ArgBegin; I != ArgEnd; ++I)
34     ParamTys.push_back(I->getType());
35   M.getOrInsertFunction(Name, FunctionType::get(RetTy, ParamTys, false));
36 }
37 
38 static void EnsureFPIntrinsicsExist(Module &M, Function &Fn,
39                                     const char *FName,
40                                     const char *DName, const char *LDName) {
41   // Insert definitions for all the floating point types.
42   switch((int)Fn.arg_begin()->getType()->getTypeID()) {
43   case Type::FloatTyID:
44     EnsureFunctionExists(M, FName, Fn.arg_begin(), Fn.arg_end(),
45                          Type::getFloatTy(M.getContext()));
46     break;
47   case Type::DoubleTyID:
48     EnsureFunctionExists(M, DName, Fn.arg_begin(), Fn.arg_end(),
49                          Type::getDoubleTy(M.getContext()));
50     break;
51   case Type::X86_FP80TyID:
52   case Type::FP128TyID:
53   case Type::PPC_FP128TyID:
54     EnsureFunctionExists(M, LDName, Fn.arg_begin(), Fn.arg_end(),
55                          Fn.arg_begin()->getType());
56     break;
57   }
58 }
59 
60 /// This function is used when we want to lower an intrinsic call to a call of
61 /// an external function. This handles hard cases such as when there was already
62 /// a prototype for the external function, but that prototype doesn't match the
63 /// arguments we expect to pass in.
64 template <class ArgIt>
65 static CallInst *ReplaceCallWith(const char *NewFn, CallInst *CI,
66                                  ArgIt ArgBegin, ArgIt ArgEnd,
67                                  Type *RetTy) {
68   // If we haven't already looked up this function, check to see if the
69   // program already contains a function with this name.
70   Module *M = CI->getModule();
71   // Get or insert the definition now.
72   std::vector<Type *> ParamTys;
73   for (ArgIt I = ArgBegin; I != ArgEnd; ++I)
74     ParamTys.push_back((*I)->getType());
75   Constant* FCache = M->getOrInsertFunction(NewFn,
76                                   FunctionType::get(RetTy, ParamTys, false));
77 
78   IRBuilder<> Builder(CI->getParent(), CI->getIterator());
79   SmallVector<Value *, 8> Args(ArgBegin, ArgEnd);
80   CallInst *NewCI = Builder.CreateCall(FCache, Args);
81   NewCI->setName(CI->getName());
82   if (!CI->use_empty())
83     CI->replaceAllUsesWith(NewCI);
84   return NewCI;
85 }
86 
87 // VisualStudio defines setjmp as _setjmp
88 #if defined(_MSC_VER) && defined(setjmp) && \
89                          !defined(setjmp_undefined_for_msvc)
90 #  pragma push_macro("setjmp")
91 #  undef setjmp
92 #  define setjmp_undefined_for_msvc
93 #endif
94 
95 void IntrinsicLowering::AddPrototypes(Module &M) {
96   LLVMContext &Context = M.getContext();
97   for (auto &F : M)
98     if (F.isDeclaration() && !F.use_empty())
99       switch (F.getIntrinsicID()) {
100       default: break;
101       case Intrinsic::setjmp:
102         EnsureFunctionExists(M, "setjmp", F.arg_begin(), F.arg_end(),
103                              Type::getInt32Ty(M.getContext()));
104         break;
105       case Intrinsic::longjmp:
106         EnsureFunctionExists(M, "longjmp", F.arg_begin(), F.arg_end(),
107                              Type::getVoidTy(M.getContext()));
108         break;
109       case Intrinsic::siglongjmp:
110         EnsureFunctionExists(M, "abort", F.arg_end(), F.arg_end(),
111                              Type::getVoidTy(M.getContext()));
112         break;
113       case Intrinsic::memcpy:
114         M.getOrInsertFunction("memcpy",
115           Type::getInt8PtrTy(Context),
116                               Type::getInt8PtrTy(Context),
117                               Type::getInt8PtrTy(Context),
118                               DL.getIntPtrType(Context));
119         break;
120       case Intrinsic::memmove:
121         M.getOrInsertFunction("memmove",
122           Type::getInt8PtrTy(Context),
123                               Type::getInt8PtrTy(Context),
124                               Type::getInt8PtrTy(Context),
125                               DL.getIntPtrType(Context));
126         break;
127       case Intrinsic::memset:
128         M.getOrInsertFunction("memset",
129           Type::getInt8PtrTy(Context),
130                               Type::getInt8PtrTy(Context),
131                               Type::getInt32Ty(M.getContext()),
132                               DL.getIntPtrType(Context));
133         break;
134       case Intrinsic::sqrt:
135         EnsureFPIntrinsicsExist(M, F, "sqrtf", "sqrt", "sqrtl");
136         break;
137       case Intrinsic::sin:
138         EnsureFPIntrinsicsExist(M, F, "sinf", "sin", "sinl");
139         break;
140       case Intrinsic::cos:
141         EnsureFPIntrinsicsExist(M, F, "cosf", "cos", "cosl");
142         break;
143       case Intrinsic::pow:
144         EnsureFPIntrinsicsExist(M, F, "powf", "pow", "powl");
145         break;
146       case Intrinsic::log:
147         EnsureFPIntrinsicsExist(M, F, "logf", "log", "logl");
148         break;
149       case Intrinsic::log2:
150         EnsureFPIntrinsicsExist(M, F, "log2f", "log2", "log2l");
151         break;
152       case Intrinsic::log10:
153         EnsureFPIntrinsicsExist(M, F, "log10f", "log10", "log10l");
154         break;
155       case Intrinsic::exp:
156         EnsureFPIntrinsicsExist(M, F, "expf", "exp", "expl");
157         break;
158       case Intrinsic::exp2:
159         EnsureFPIntrinsicsExist(M, F, "exp2f", "exp2", "exp2l");
160         break;
161       }
162 }
163 
164 /// Emit the code to lower bswap of V before the specified instruction IP.
165 static Value *LowerBSWAP(LLVMContext &Context, Value *V, Instruction *IP) {
166   assert(V->getType()->isIntOrIntVectorTy() && "Can't bswap a non-integer type!");
167 
168   unsigned BitSize = V->getType()->getScalarSizeInBits();
169 
170   IRBuilder<> Builder(IP);
171 
172   switch(BitSize) {
173   default: llvm_unreachable("Unhandled type size of value to byteswap!");
174   case 16: {
175     Value *Tmp1 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 8),
176                                     "bswap.2");
177     Value *Tmp2 = Builder.CreateLShr(V, ConstantInt::get(V->getType(), 8),
178                                      "bswap.1");
179     V = Builder.CreateOr(Tmp1, Tmp2, "bswap.i16");
180     break;
181   }
182   case 32: {
183     Value *Tmp4 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 24),
184                                     "bswap.4");
185     Value *Tmp3 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 8),
186                                     "bswap.3");
187     Value *Tmp2 = Builder.CreateLShr(V, ConstantInt::get(V->getType(), 8),
188                                      "bswap.2");
189     Value *Tmp1 = Builder.CreateLShr(V,ConstantInt::get(V->getType(), 24),
190                                      "bswap.1");
191     Tmp3 = Builder.CreateAnd(Tmp3,
192                          ConstantInt::get(V->getType(), 0xFF0000),
193                              "bswap.and3");
194     Tmp2 = Builder.CreateAnd(Tmp2,
195                            ConstantInt::get(V->getType(), 0xFF00),
196                              "bswap.and2");
197     Tmp4 = Builder.CreateOr(Tmp4, Tmp3, "bswap.or1");
198     Tmp2 = Builder.CreateOr(Tmp2, Tmp1, "bswap.or2");
199     V = Builder.CreateOr(Tmp4, Tmp2, "bswap.i32");
200     break;
201   }
202   case 64: {
203     Value *Tmp8 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 56),
204                                     "bswap.8");
205     Value *Tmp7 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 40),
206                                     "bswap.7");
207     Value *Tmp6 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 24),
208                                     "bswap.6");
209     Value *Tmp5 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 8),
210                                     "bswap.5");
211     Value* Tmp4 = Builder.CreateLShr(V, ConstantInt::get(V->getType(), 8),
212                                      "bswap.4");
213     Value* Tmp3 = Builder.CreateLShr(V,
214                                      ConstantInt::get(V->getType(), 24),
215                                      "bswap.3");
216     Value* Tmp2 = Builder.CreateLShr(V,
217                                      ConstantInt::get(V->getType(), 40),
218                                      "bswap.2");
219     Value* Tmp1 = Builder.CreateLShr(V,
220                                      ConstantInt::get(V->getType(), 56),
221                                      "bswap.1");
222     Tmp7 = Builder.CreateAnd(Tmp7,
223                              ConstantInt::get(V->getType(),
224                                               0xFF000000000000ULL),
225                              "bswap.and7");
226     Tmp6 = Builder.CreateAnd(Tmp6,
227                              ConstantInt::get(V->getType(),
228                                               0xFF0000000000ULL),
229                              "bswap.and6");
230     Tmp5 = Builder.CreateAnd(Tmp5,
231                         ConstantInt::get(V->getType(),
232                              0xFF00000000ULL),
233                              "bswap.and5");
234     Tmp4 = Builder.CreateAnd(Tmp4,
235                         ConstantInt::get(V->getType(),
236                              0xFF000000ULL),
237                              "bswap.and4");
238     Tmp3 = Builder.CreateAnd(Tmp3,
239                              ConstantInt::get(V->getType(),
240                              0xFF0000ULL),
241                              "bswap.and3");
242     Tmp2 = Builder.CreateAnd(Tmp2,
243                              ConstantInt::get(V->getType(),
244                              0xFF00ULL),
245                              "bswap.and2");
246     Tmp8 = Builder.CreateOr(Tmp8, Tmp7, "bswap.or1");
247     Tmp6 = Builder.CreateOr(Tmp6, Tmp5, "bswap.or2");
248     Tmp4 = Builder.CreateOr(Tmp4, Tmp3, "bswap.or3");
249     Tmp2 = Builder.CreateOr(Tmp2, Tmp1, "bswap.or4");
250     Tmp8 = Builder.CreateOr(Tmp8, Tmp6, "bswap.or5");
251     Tmp4 = Builder.CreateOr(Tmp4, Tmp2, "bswap.or6");
252     V = Builder.CreateOr(Tmp8, Tmp4, "bswap.i64");
253     break;
254   }
255   }
256   return V;
257 }
258 
259 /// Emit the code to lower ctpop of V before the specified instruction IP.
260 static Value *LowerCTPOP(LLVMContext &Context, Value *V, Instruction *IP) {
261   assert(V->getType()->isIntegerTy() && "Can't ctpop a non-integer type!");
262 
263   static const uint64_t MaskValues[6] = {
264     0x5555555555555555ULL, 0x3333333333333333ULL,
265     0x0F0F0F0F0F0F0F0FULL, 0x00FF00FF00FF00FFULL,
266     0x0000FFFF0000FFFFULL, 0x00000000FFFFFFFFULL
267   };
268 
269   IRBuilder<> Builder(IP);
270 
271   unsigned BitSize = V->getType()->getPrimitiveSizeInBits();
272   unsigned WordSize = (BitSize + 63) / 64;
273   Value *Count = ConstantInt::get(V->getType(), 0);
274 
275   for (unsigned n = 0; n < WordSize; ++n) {
276     Value *PartValue = V;
277     for (unsigned i = 1, ct = 0; i < (BitSize>64 ? 64 : BitSize);
278          i <<= 1, ++ct) {
279       Value *MaskCst = ConstantInt::get(V->getType(), MaskValues[ct]);
280       Value *LHS = Builder.CreateAnd(PartValue, MaskCst, "cppop.and1");
281       Value *VShift = Builder.CreateLShr(PartValue,
282                                         ConstantInt::get(V->getType(), i),
283                                          "ctpop.sh");
284       Value *RHS = Builder.CreateAnd(VShift, MaskCst, "cppop.and2");
285       PartValue = Builder.CreateAdd(LHS, RHS, "ctpop.step");
286     }
287     Count = Builder.CreateAdd(PartValue, Count, "ctpop.part");
288     if (BitSize > 64) {
289       V = Builder.CreateLShr(V, ConstantInt::get(V->getType(), 64),
290                              "ctpop.part.sh");
291       BitSize -= 64;
292     }
293   }
294 
295   return Count;
296 }
297 
298 /// Emit the code to lower ctlz of V before the specified instruction IP.
299 static Value *LowerCTLZ(LLVMContext &Context, Value *V, Instruction *IP) {
300 
301   IRBuilder<> Builder(IP);
302 
303   unsigned BitSize = V->getType()->getPrimitiveSizeInBits();
304   for (unsigned i = 1; i < BitSize; i <<= 1) {
305     Value *ShVal = ConstantInt::get(V->getType(), i);
306     ShVal = Builder.CreateLShr(V, ShVal, "ctlz.sh");
307     V = Builder.CreateOr(V, ShVal, "ctlz.step");
308   }
309 
310   V = Builder.CreateNot(V);
311   return LowerCTPOP(Context, V, IP);
312 }
313 
314 static void ReplaceFPIntrinsicWithCall(CallInst *CI, const char *Fname,
315                                        const char *Dname,
316                                        const char *LDname) {
317   CallSite CS(CI);
318   switch (CI->getArgOperand(0)->getType()->getTypeID()) {
319   default: llvm_unreachable("Invalid type in intrinsic");
320   case Type::FloatTyID:
321     ReplaceCallWith(Fname, CI, CS.arg_begin(), CS.arg_end(),
322                   Type::getFloatTy(CI->getContext()));
323     break;
324   case Type::DoubleTyID:
325     ReplaceCallWith(Dname, CI, CS.arg_begin(), CS.arg_end(),
326                   Type::getDoubleTy(CI->getContext()));
327     break;
328   case Type::X86_FP80TyID:
329   case Type::FP128TyID:
330   case Type::PPC_FP128TyID:
331     ReplaceCallWith(LDname, CI, CS.arg_begin(), CS.arg_end(),
332                   CI->getArgOperand(0)->getType());
333     break;
334   }
335 }
336 
337 void IntrinsicLowering::LowerIntrinsicCall(CallInst *CI) {
338   IRBuilder<> Builder(CI);
339   LLVMContext &Context = CI->getContext();
340 
341   const Function *Callee = CI->getCalledFunction();
342   assert(Callee && "Cannot lower an indirect call!");
343 
344   CallSite CS(CI);
345   switch (Callee->getIntrinsicID()) {
346   case Intrinsic::not_intrinsic:
347     report_fatal_error("Cannot lower a call to a non-intrinsic function '"+
348                       Callee->getName() + "'!");
349   default:
350     report_fatal_error("Code generator does not support intrinsic function '"+
351                       Callee->getName()+"'!");
352 
353   case Intrinsic::expect: {
354     // Just replace __builtin_expect(exp, c) with EXP.
355     Value *V = CI->getArgOperand(0);
356     CI->replaceAllUsesWith(V);
357     break;
358   }
359 
360     // The setjmp/longjmp intrinsics should only exist in the code if it was
361     // never optimized (ie, right out of the CFE), or if it has been hacked on
362     // by the lowerinvoke pass.  In both cases, the right thing to do is to
363     // convert the call to an explicit setjmp or longjmp call.
364   case Intrinsic::setjmp: {
365     Value *V = ReplaceCallWith("setjmp", CI, CS.arg_begin(), CS.arg_end(),
366                                Type::getInt32Ty(Context));
367     if (!CI->getType()->isVoidTy())
368       CI->replaceAllUsesWith(V);
369     break;
370   }
371   case Intrinsic::sigsetjmp:
372      if (!CI->getType()->isVoidTy())
373        CI->replaceAllUsesWith(Constant::getNullValue(CI->getType()));
374      break;
375 
376   case Intrinsic::longjmp: {
377     ReplaceCallWith("longjmp", CI, CS.arg_begin(), CS.arg_end(),
378                     Type::getVoidTy(Context));
379     break;
380   }
381 
382   case Intrinsic::siglongjmp: {
383     // Insert the call to abort
384     ReplaceCallWith("abort", CI, CS.arg_end(), CS.arg_end(),
385                     Type::getVoidTy(Context));
386     break;
387   }
388   case Intrinsic::ctpop:
389     CI->replaceAllUsesWith(LowerCTPOP(Context, CI->getArgOperand(0), CI));
390     break;
391 
392   case Intrinsic::bswap:
393     CI->replaceAllUsesWith(LowerBSWAP(Context, CI->getArgOperand(0), CI));
394     break;
395 
396   case Intrinsic::ctlz:
397     CI->replaceAllUsesWith(LowerCTLZ(Context, CI->getArgOperand(0), CI));
398     break;
399 
400   case Intrinsic::cttz: {
401     // cttz(x) -> ctpop(~X & (X-1))
402     Value *Src = CI->getArgOperand(0);
403     Value *NotSrc = Builder.CreateNot(Src);
404     NotSrc->setName(Src->getName() + ".not");
405     Value *SrcM1 = ConstantInt::get(Src->getType(), 1);
406     SrcM1 = Builder.CreateSub(Src, SrcM1);
407     Src = LowerCTPOP(Context, Builder.CreateAnd(NotSrc, SrcM1), CI);
408     CI->replaceAllUsesWith(Src);
409     break;
410   }
411 
412   case Intrinsic::stacksave:
413   case Intrinsic::stackrestore: {
414     if (!Warned)
415       errs() << "WARNING: this target does not support the llvm.stack"
416              << (Callee->getIntrinsicID() == Intrinsic::stacksave ?
417                "save" : "restore") << " intrinsic.\n";
418     Warned = true;
419     if (Callee->getIntrinsicID() == Intrinsic::stacksave)
420       CI->replaceAllUsesWith(Constant::getNullValue(CI->getType()));
421     break;
422   }
423 
424   case Intrinsic::get_dynamic_area_offset:
425     errs() << "WARNING: this target does not support the custom llvm.get."
426               "dynamic.area.offset.  It is being lowered to a constant 0\n";
427     // Just lower it to a constant 0 because for most targets
428     // @llvm.get.dynamic.area.offset is lowered to zero.
429     CI->replaceAllUsesWith(ConstantInt::get(CI->getType(), 0));
430     break;
431   case Intrinsic::returnaddress:
432   case Intrinsic::frameaddress:
433     errs() << "WARNING: this target does not support the llvm."
434            << (Callee->getIntrinsicID() == Intrinsic::returnaddress ?
435              "return" : "frame") << "address intrinsic.\n";
436     CI->replaceAllUsesWith(
437         ConstantPointerNull::get(cast<PointerType>(CI->getType())));
438     break;
439   case Intrinsic::addressofreturnaddress:
440     errs() << "WARNING: this target does not support the "
441               "llvm.addressofreturnaddress intrinsic.\n";
442     CI->replaceAllUsesWith(
443         ConstantPointerNull::get(cast<PointerType>(CI->getType())));
444     break;
445 
446   case Intrinsic::prefetch:
447     break;    // Simply strip out prefetches on unsupported architectures
448 
449   case Intrinsic::pcmarker:
450     break;    // Simply strip out pcmarker on unsupported architectures
451   case Intrinsic::readcyclecounter: {
452     errs() << "WARNING: this target does not support the llvm.readcyclecoun"
453            << "ter intrinsic.  It is being lowered to a constant 0\n";
454     CI->replaceAllUsesWith(ConstantInt::get(Type::getInt64Ty(Context), 0));
455     break;
456   }
457 
458   case Intrinsic::dbg_declare:
459     break;    // Simply strip out debugging intrinsics
460 
461   case Intrinsic::eh_typeid_for:
462     // Return something different to eh_selector.
463     CI->replaceAllUsesWith(ConstantInt::get(CI->getType(), 1));
464     break;
465 
466   case Intrinsic::annotation:
467   case Intrinsic::ptr_annotation:
468     // Just drop the annotation, but forward the value
469     CI->replaceAllUsesWith(CI->getOperand(0));
470     break;
471 
472   case Intrinsic::assume:
473   case Intrinsic::var_annotation:
474     break;   // Strip out these intrinsics
475 
476   case Intrinsic::memcpy: {
477     Type *IntPtr = DL.getIntPtrType(Context);
478     Value *Size = Builder.CreateIntCast(CI->getArgOperand(2), IntPtr,
479                                         /* isSigned */ false);
480     Value *Ops[3];
481     Ops[0] = CI->getArgOperand(0);
482     Ops[1] = CI->getArgOperand(1);
483     Ops[2] = Size;
484     ReplaceCallWith("memcpy", CI, Ops, Ops+3, CI->getArgOperand(0)->getType());
485     break;
486   }
487   case Intrinsic::memmove: {
488     Type *IntPtr = DL.getIntPtrType(Context);
489     Value *Size = Builder.CreateIntCast(CI->getArgOperand(2), IntPtr,
490                                         /* isSigned */ false);
491     Value *Ops[3];
492     Ops[0] = CI->getArgOperand(0);
493     Ops[1] = CI->getArgOperand(1);
494     Ops[2] = Size;
495     ReplaceCallWith("memmove", CI, Ops, Ops+3, CI->getArgOperand(0)->getType());
496     break;
497   }
498   case Intrinsic::memset: {
499     Value *Op0 = CI->getArgOperand(0);
500     Type *IntPtr = DL.getIntPtrType(Op0->getType());
501     Value *Size = Builder.CreateIntCast(CI->getArgOperand(2), IntPtr,
502                                         /* isSigned */ false);
503     Value *Ops[3];
504     Ops[0] = Op0;
505     // Extend the amount to i32.
506     Ops[1] = Builder.CreateIntCast(CI->getArgOperand(1),
507                                    Type::getInt32Ty(Context),
508                                    /* isSigned */ false);
509     Ops[2] = Size;
510     ReplaceCallWith("memset", CI, Ops, Ops+3, CI->getArgOperand(0)->getType());
511     break;
512   }
513   case Intrinsic::sqrt: {
514     ReplaceFPIntrinsicWithCall(CI, "sqrtf", "sqrt", "sqrtl");
515     break;
516   }
517   case Intrinsic::log: {
518     ReplaceFPIntrinsicWithCall(CI, "logf", "log", "logl");
519     break;
520   }
521   case Intrinsic::log2: {
522     ReplaceFPIntrinsicWithCall(CI, "log2f", "log2", "log2l");
523     break;
524   }
525   case Intrinsic::log10: {
526     ReplaceFPIntrinsicWithCall(CI, "log10f", "log10", "log10l");
527     break;
528   }
529   case Intrinsic::exp: {
530     ReplaceFPIntrinsicWithCall(CI, "expf", "exp", "expl");
531     break;
532   }
533   case Intrinsic::exp2: {
534     ReplaceFPIntrinsicWithCall(CI, "exp2f", "exp2", "exp2l");
535     break;
536   }
537   case Intrinsic::pow: {
538     ReplaceFPIntrinsicWithCall(CI, "powf", "pow", "powl");
539     break;
540   }
541   case Intrinsic::sin: {
542     ReplaceFPIntrinsicWithCall(CI, "sinf", "sin", "sinl");
543     break;
544   }
545   case Intrinsic::cos: {
546     ReplaceFPIntrinsicWithCall(CI, "cosf", "cos", "cosl");
547     break;
548   }
549   case Intrinsic::floor: {
550     ReplaceFPIntrinsicWithCall(CI, "floorf", "floor", "floorl");
551     break;
552   }
553   case Intrinsic::ceil: {
554     ReplaceFPIntrinsicWithCall(CI, "ceilf", "ceil", "ceill");
555     break;
556   }
557   case Intrinsic::trunc: {
558     ReplaceFPIntrinsicWithCall(CI, "truncf", "trunc", "truncl");
559     break;
560   }
561   case Intrinsic::round: {
562     ReplaceFPIntrinsicWithCall(CI, "roundf", "round", "roundl");
563     break;
564   }
565   case Intrinsic::copysign: {
566     ReplaceFPIntrinsicWithCall(CI, "copysignf", "copysign", "copysignl");
567     break;
568   }
569   case Intrinsic::flt_rounds:
570      // Lower to "round to the nearest"
571      if (!CI->getType()->isVoidTy())
572        CI->replaceAllUsesWith(ConstantInt::get(CI->getType(), 1));
573      break;
574   case Intrinsic::invariant_start:
575   case Intrinsic::lifetime_start:
576     // Discard region information.
577     CI->replaceAllUsesWith(UndefValue::get(CI->getType()));
578     break;
579   case Intrinsic::invariant_end:
580   case Intrinsic::lifetime_end:
581     // Discard region information.
582     break;
583   }
584 
585   assert(CI->use_empty() &&
586          "Lowering should have eliminated any uses of the intrinsic call!");
587   CI->eraseFromParent();
588 }
589 
590 bool IntrinsicLowering::LowerToByteSwap(CallInst *CI) {
591   // Verify this is a simple bswap.
592   if (CI->getNumArgOperands() != 1 ||
593       CI->getType() != CI->getArgOperand(0)->getType() ||
594       !CI->getType()->isIntegerTy())
595     return false;
596 
597   IntegerType *Ty = dyn_cast<IntegerType>(CI->getType());
598   if (!Ty)
599     return false;
600 
601   // Okay, we can do this xform, do so now.
602   Module *M = CI->getModule();
603   Constant *Int = Intrinsic::getDeclaration(M, Intrinsic::bswap, Ty);
604 
605   Value *Op = CI->getArgOperand(0);
606   Op = CallInst::Create(Int, Op, CI->getName(), CI);
607 
608   CI->replaceAllUsesWith(Op);
609   CI->eraseFromParent();
610   return true;
611 }
612