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/Constants.h"
17 #include "llvm/IR/DataLayout.h"
18 #include "llvm/IR/DerivedTypes.h"
19 #include "llvm/IR/IRBuilder.h"
20 #include "llvm/IR/Module.h"
21 #include "llvm/IR/Type.h"
22 #include "llvm/Support/CallSite.h"
23 #include "llvm/Support/ErrorHandling.h"
24 #include "llvm/Support/raw_ostream.h"
25 using namespace llvm;
26
27 template <class ArgIt>
EnsureFunctionExists(Module & M,const char * Name,ArgIt ArgBegin,ArgIt ArgEnd,Type * RetTy)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
EnsureFPIntrinsicsExist(Module & M,Function * Fn,const char * FName,const char * DName,const char * LDName)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 /// ReplaceCallWith - This function is used when we want to lower an intrinsic
61 /// call to a call of an external function. This handles hard cases such as
62 /// when there was already a prototype for the external function, and if that
63 /// prototype doesn't match the arguments we expect to pass in.
64 template <class ArgIt>
ReplaceCallWith(const char * NewFn,CallInst * CI,ArgIt ArgBegin,ArgIt ArgEnd,Type * RetTy)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->getParent()->getParent()->getParent();
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);
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
AddPrototypes(Module & M)95 void IntrinsicLowering::AddPrototypes(Module &M) {
96 LLVMContext &Context = M.getContext();
97 for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
98 if (I->isDeclaration() && !I->use_empty())
99 switch (I->getIntrinsicID()) {
100 default: break;
101 case Intrinsic::setjmp:
102 EnsureFunctionExists(M, "setjmp", I->arg_begin(), I->arg_end(),
103 Type::getInt32Ty(M.getContext()));
104 break;
105 case Intrinsic::longjmp:
106 EnsureFunctionExists(M, "longjmp", I->arg_begin(), I->arg_end(),
107 Type::getVoidTy(M.getContext()));
108 break;
109 case Intrinsic::siglongjmp:
110 EnsureFunctionExists(M, "abort", I->arg_end(), I->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 TD.getIntPtrType(Context), (Type *)0);
119 break;
120 case Intrinsic::memmove:
121 M.getOrInsertFunction("memmove",
122 Type::getInt8PtrTy(Context),
123 Type::getInt8PtrTy(Context),
124 Type::getInt8PtrTy(Context),
125 TD.getIntPtrType(Context), (Type *)0);
126 break;
127 case Intrinsic::memset:
128 M.getOrInsertFunction("memset",
129 Type::getInt8PtrTy(Context),
130 Type::getInt8PtrTy(Context),
131 Type::getInt32Ty(M.getContext()),
132 TD.getIntPtrType(Context), (Type *)0);
133 break;
134 case Intrinsic::sqrt:
135 EnsureFPIntrinsicsExist(M, I, "sqrtf", "sqrt", "sqrtl");
136 break;
137 case Intrinsic::sin:
138 EnsureFPIntrinsicsExist(M, I, "sinf", "sin", "sinl");
139 break;
140 case Intrinsic::cos:
141 EnsureFPIntrinsicsExist(M, I, "cosf", "cos", "cosl");
142 break;
143 case Intrinsic::pow:
144 EnsureFPIntrinsicsExist(M, I, "powf", "pow", "powl");
145 break;
146 case Intrinsic::log:
147 EnsureFPIntrinsicsExist(M, I, "logf", "log", "logl");
148 break;
149 case Intrinsic::log2:
150 EnsureFPIntrinsicsExist(M, I, "log2f", "log2", "log2l");
151 break;
152 case Intrinsic::log10:
153 EnsureFPIntrinsicsExist(M, I, "log10f", "log10", "log10l");
154 break;
155 case Intrinsic::exp:
156 EnsureFPIntrinsicsExist(M, I, "expf", "exp", "expl");
157 break;
158 case Intrinsic::exp2:
159 EnsureFPIntrinsicsExist(M, I, "exp2f", "exp2", "exp2l");
160 break;
161 }
162 }
163
164 /// LowerBSWAP - Emit the code to lower bswap of V before the specified
165 /// instruction IP.
LowerBSWAP(LLVMContext & Context,Value * V,Instruction * IP)166 static Value *LowerBSWAP(LLVMContext &Context, Value *V, Instruction *IP) {
167 assert(V->getType()->isIntegerTy() && "Can't bswap a non-integer type!");
168
169 unsigned BitSize = V->getType()->getPrimitiveSizeInBits();
170
171 IRBuilder<> Builder(IP->getParent(), IP);
172
173 switch(BitSize) {
174 default: llvm_unreachable("Unhandled type size of value to byteswap!");
175 case 16: {
176 Value *Tmp1 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 8),
177 "bswap.2");
178 Value *Tmp2 = Builder.CreateLShr(V, ConstantInt::get(V->getType(), 8),
179 "bswap.1");
180 V = Builder.CreateOr(Tmp1, Tmp2, "bswap.i16");
181 break;
182 }
183 case 32: {
184 Value *Tmp4 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 24),
185 "bswap.4");
186 Value *Tmp3 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 8),
187 "bswap.3");
188 Value *Tmp2 = Builder.CreateLShr(V, ConstantInt::get(V->getType(), 8),
189 "bswap.2");
190 Value *Tmp1 = Builder.CreateLShr(V,ConstantInt::get(V->getType(), 24),
191 "bswap.1");
192 Tmp3 = Builder.CreateAnd(Tmp3,
193 ConstantInt::get(Type::getInt32Ty(Context), 0xFF0000),
194 "bswap.and3");
195 Tmp2 = Builder.CreateAnd(Tmp2,
196 ConstantInt::get(Type::getInt32Ty(Context), 0xFF00),
197 "bswap.and2");
198 Tmp4 = Builder.CreateOr(Tmp4, Tmp3, "bswap.or1");
199 Tmp2 = Builder.CreateOr(Tmp2, Tmp1, "bswap.or2");
200 V = Builder.CreateOr(Tmp4, Tmp2, "bswap.i32");
201 break;
202 }
203 case 64: {
204 Value *Tmp8 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 56),
205 "bswap.8");
206 Value *Tmp7 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 40),
207 "bswap.7");
208 Value *Tmp6 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 24),
209 "bswap.6");
210 Value *Tmp5 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 8),
211 "bswap.5");
212 Value* Tmp4 = Builder.CreateLShr(V, ConstantInt::get(V->getType(), 8),
213 "bswap.4");
214 Value* Tmp3 = Builder.CreateLShr(V,
215 ConstantInt::get(V->getType(), 24),
216 "bswap.3");
217 Value* Tmp2 = Builder.CreateLShr(V,
218 ConstantInt::get(V->getType(), 40),
219 "bswap.2");
220 Value* Tmp1 = Builder.CreateLShr(V,
221 ConstantInt::get(V->getType(), 56),
222 "bswap.1");
223 Tmp7 = Builder.CreateAnd(Tmp7,
224 ConstantInt::get(Type::getInt64Ty(Context),
225 0xFF000000000000ULL),
226 "bswap.and7");
227 Tmp6 = Builder.CreateAnd(Tmp6,
228 ConstantInt::get(Type::getInt64Ty(Context),
229 0xFF0000000000ULL),
230 "bswap.and6");
231 Tmp5 = Builder.CreateAnd(Tmp5,
232 ConstantInt::get(Type::getInt64Ty(Context),
233 0xFF00000000ULL),
234 "bswap.and5");
235 Tmp4 = Builder.CreateAnd(Tmp4,
236 ConstantInt::get(Type::getInt64Ty(Context),
237 0xFF000000ULL),
238 "bswap.and4");
239 Tmp3 = Builder.CreateAnd(Tmp3,
240 ConstantInt::get(Type::getInt64Ty(Context),
241 0xFF0000ULL),
242 "bswap.and3");
243 Tmp2 = Builder.CreateAnd(Tmp2,
244 ConstantInt::get(Type::getInt64Ty(Context),
245 0xFF00ULL),
246 "bswap.and2");
247 Tmp8 = Builder.CreateOr(Tmp8, Tmp7, "bswap.or1");
248 Tmp6 = Builder.CreateOr(Tmp6, Tmp5, "bswap.or2");
249 Tmp4 = Builder.CreateOr(Tmp4, Tmp3, "bswap.or3");
250 Tmp2 = Builder.CreateOr(Tmp2, Tmp1, "bswap.or4");
251 Tmp8 = Builder.CreateOr(Tmp8, Tmp6, "bswap.or5");
252 Tmp4 = Builder.CreateOr(Tmp4, Tmp2, "bswap.or6");
253 V = Builder.CreateOr(Tmp8, Tmp4, "bswap.i64");
254 break;
255 }
256 }
257 return V;
258 }
259
260 /// LowerCTPOP - Emit the code to lower ctpop of V before the specified
261 /// instruction IP.
LowerCTPOP(LLVMContext & Context,Value * V,Instruction * IP)262 static Value *LowerCTPOP(LLVMContext &Context, Value *V, Instruction *IP) {
263 assert(V->getType()->isIntegerTy() && "Can't ctpop a non-integer type!");
264
265 static const uint64_t MaskValues[6] = {
266 0x5555555555555555ULL, 0x3333333333333333ULL,
267 0x0F0F0F0F0F0F0F0FULL, 0x00FF00FF00FF00FFULL,
268 0x0000FFFF0000FFFFULL, 0x00000000FFFFFFFFULL
269 };
270
271 IRBuilder<> Builder(IP->getParent(), IP);
272
273 unsigned BitSize = V->getType()->getPrimitiveSizeInBits();
274 unsigned WordSize = (BitSize + 63) / 64;
275 Value *Count = ConstantInt::get(V->getType(), 0);
276
277 for (unsigned n = 0; n < WordSize; ++n) {
278 Value *PartValue = V;
279 for (unsigned i = 1, ct = 0; i < (BitSize>64 ? 64 : BitSize);
280 i <<= 1, ++ct) {
281 Value *MaskCst = ConstantInt::get(V->getType(), MaskValues[ct]);
282 Value *LHS = Builder.CreateAnd(PartValue, MaskCst, "cppop.and1");
283 Value *VShift = Builder.CreateLShr(PartValue,
284 ConstantInt::get(V->getType(), i),
285 "ctpop.sh");
286 Value *RHS = Builder.CreateAnd(VShift, MaskCst, "cppop.and2");
287 PartValue = Builder.CreateAdd(LHS, RHS, "ctpop.step");
288 }
289 Count = Builder.CreateAdd(PartValue, Count, "ctpop.part");
290 if (BitSize > 64) {
291 V = Builder.CreateLShr(V, ConstantInt::get(V->getType(), 64),
292 "ctpop.part.sh");
293 BitSize -= 64;
294 }
295 }
296
297 return Count;
298 }
299
300 /// LowerCTLZ - Emit the code to lower ctlz of V before the specified
301 /// instruction IP.
LowerCTLZ(LLVMContext & Context,Value * V,Instruction * IP)302 static Value *LowerCTLZ(LLVMContext &Context, Value *V, Instruction *IP) {
303
304 IRBuilder<> Builder(IP->getParent(), IP);
305
306 unsigned BitSize = V->getType()->getPrimitiveSizeInBits();
307 for (unsigned i = 1; i < BitSize; i <<= 1) {
308 Value *ShVal = ConstantInt::get(V->getType(), i);
309 ShVal = Builder.CreateLShr(V, ShVal, "ctlz.sh");
310 V = Builder.CreateOr(V, ShVal, "ctlz.step");
311 }
312
313 V = Builder.CreateNot(V);
314 return LowerCTPOP(Context, V, IP);
315 }
316
ReplaceFPIntrinsicWithCall(CallInst * CI,const char * Fname,const char * Dname,const char * LDname)317 static void ReplaceFPIntrinsicWithCall(CallInst *CI, const char *Fname,
318 const char *Dname,
319 const char *LDname) {
320 CallSite CS(CI);
321 switch (CI->getArgOperand(0)->getType()->getTypeID()) {
322 default: llvm_unreachable("Invalid type in intrinsic");
323 case Type::FloatTyID:
324 ReplaceCallWith(Fname, CI, CS.arg_begin(), CS.arg_end(),
325 Type::getFloatTy(CI->getContext()));
326 break;
327 case Type::DoubleTyID:
328 ReplaceCallWith(Dname, CI, CS.arg_begin(), CS.arg_end(),
329 Type::getDoubleTy(CI->getContext()));
330 break;
331 case Type::X86_FP80TyID:
332 case Type::FP128TyID:
333 case Type::PPC_FP128TyID:
334 ReplaceCallWith(LDname, CI, CS.arg_begin(), CS.arg_end(),
335 CI->getArgOperand(0)->getType());
336 break;
337 }
338 }
339
LowerIntrinsicCall(CallInst * CI)340 void IntrinsicLowering::LowerIntrinsicCall(CallInst *CI) {
341 IRBuilder<> Builder(CI->getParent(), CI);
342 LLVMContext &Context = CI->getContext();
343
344 const Function *Callee = CI->getCalledFunction();
345 assert(Callee && "Cannot lower an indirect call!");
346
347 CallSite CS(CI);
348 switch (Callee->getIntrinsicID()) {
349 case Intrinsic::not_intrinsic:
350 report_fatal_error("Cannot lower a call to a non-intrinsic function '"+
351 Callee->getName() + "'!");
352 default:
353 report_fatal_error("Code generator does not support intrinsic function '"+
354 Callee->getName()+"'!");
355
356 case Intrinsic::expect: {
357 // Just replace __builtin_expect(exp, c) with EXP.
358 Value *V = CI->getArgOperand(0);
359 CI->replaceAllUsesWith(V);
360 break;
361 }
362
363 // The setjmp/longjmp intrinsics should only exist in the code if it was
364 // never optimized (ie, right out of the CFE), or if it has been hacked on
365 // by the lowerinvoke pass. In both cases, the right thing to do is to
366 // convert the call to an explicit setjmp or longjmp call.
367 case Intrinsic::setjmp: {
368 Value *V = ReplaceCallWith("setjmp", CI, CS.arg_begin(), CS.arg_end(),
369 Type::getInt32Ty(Context));
370 if (!CI->getType()->isVoidTy())
371 CI->replaceAllUsesWith(V);
372 break;
373 }
374 case Intrinsic::sigsetjmp:
375 if (!CI->getType()->isVoidTy())
376 CI->replaceAllUsesWith(Constant::getNullValue(CI->getType()));
377 break;
378
379 case Intrinsic::longjmp: {
380 ReplaceCallWith("longjmp", CI, CS.arg_begin(), CS.arg_end(),
381 Type::getVoidTy(Context));
382 break;
383 }
384
385 case Intrinsic::siglongjmp: {
386 // Insert the call to abort
387 ReplaceCallWith("abort", CI, CS.arg_end(), CS.arg_end(),
388 Type::getVoidTy(Context));
389 break;
390 }
391 case Intrinsic::ctpop:
392 CI->replaceAllUsesWith(LowerCTPOP(Context, CI->getArgOperand(0), CI));
393 break;
394
395 case Intrinsic::bswap:
396 CI->replaceAllUsesWith(LowerBSWAP(Context, CI->getArgOperand(0), CI));
397 break;
398
399 case Intrinsic::ctlz:
400 CI->replaceAllUsesWith(LowerCTLZ(Context, CI->getArgOperand(0), CI));
401 break;
402
403 case Intrinsic::cttz: {
404 // cttz(x) -> ctpop(~X & (X-1))
405 Value *Src = CI->getArgOperand(0);
406 Value *NotSrc = Builder.CreateNot(Src);
407 NotSrc->setName(Src->getName() + ".not");
408 Value *SrcM1 = ConstantInt::get(Src->getType(), 1);
409 SrcM1 = Builder.CreateSub(Src, SrcM1);
410 Src = LowerCTPOP(Context, Builder.CreateAnd(NotSrc, SrcM1), CI);
411 CI->replaceAllUsesWith(Src);
412 break;
413 }
414
415 case Intrinsic::stacksave:
416 case Intrinsic::stackrestore: {
417 if (!Warned)
418 errs() << "WARNING: this target does not support the llvm.stack"
419 << (Callee->getIntrinsicID() == Intrinsic::stacksave ?
420 "save" : "restore") << " intrinsic.\n";
421 Warned = true;
422 if (Callee->getIntrinsicID() == Intrinsic::stacksave)
423 CI->replaceAllUsesWith(Constant::getNullValue(CI->getType()));
424 break;
425 }
426
427 case Intrinsic::returnaddress:
428 case Intrinsic::frameaddress:
429 errs() << "WARNING: this target does not support the llvm."
430 << (Callee->getIntrinsicID() == Intrinsic::returnaddress ?
431 "return" : "frame") << "address intrinsic.\n";
432 CI->replaceAllUsesWith(ConstantPointerNull::get(
433 cast<PointerType>(CI->getType())));
434 break;
435
436 case Intrinsic::prefetch:
437 break; // Simply strip out prefetches on unsupported architectures
438
439 case Intrinsic::pcmarker:
440 break; // Simply strip out pcmarker on unsupported architectures
441 case Intrinsic::readcyclecounter: {
442 errs() << "WARNING: this target does not support the llvm.readcyclecoun"
443 << "ter intrinsic. It is being lowered to a constant 0\n";
444 CI->replaceAllUsesWith(ConstantInt::get(Type::getInt64Ty(Context), 0));
445 break;
446 }
447
448 case Intrinsic::dbg_declare:
449 break; // Simply strip out debugging intrinsics
450
451 case Intrinsic::eh_typeid_for:
452 // Return something different to eh_selector.
453 CI->replaceAllUsesWith(ConstantInt::get(CI->getType(), 1));
454 break;
455
456 case Intrinsic::annotation:
457 case Intrinsic::ptr_annotation:
458 // Just drop the annotation, but forward the value
459 CI->replaceAllUsesWith(CI->getOperand(0));
460 break;
461
462 case Intrinsic::var_annotation:
463 break; // Strip out annotate intrinsic
464
465 case Intrinsic::memcpy: {
466 Type *IntPtr = TD.getIntPtrType(Context);
467 Value *Size = Builder.CreateIntCast(CI->getArgOperand(2), IntPtr,
468 /* isSigned */ false);
469 Value *Ops[3];
470 Ops[0] = CI->getArgOperand(0);
471 Ops[1] = CI->getArgOperand(1);
472 Ops[2] = Size;
473 ReplaceCallWith("memcpy", CI, Ops, Ops+3, CI->getArgOperand(0)->getType());
474 break;
475 }
476 case Intrinsic::memmove: {
477 Type *IntPtr = TD.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("memmove", CI, Ops, Ops+3, CI->getArgOperand(0)->getType());
485 break;
486 }
487 case Intrinsic::memset: {
488 Type *IntPtr = TD.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 // Extend the amount to i32.
494 Ops[1] = Builder.CreateIntCast(CI->getArgOperand(1),
495 Type::getInt32Ty(Context),
496 /* isSigned */ false);
497 Ops[2] = Size;
498 ReplaceCallWith("memset", CI, Ops, Ops+3, CI->getArgOperand(0)->getType());
499 break;
500 }
501 case Intrinsic::sqrt: {
502 ReplaceFPIntrinsicWithCall(CI, "sqrtf", "sqrt", "sqrtl");
503 break;
504 }
505 case Intrinsic::log: {
506 ReplaceFPIntrinsicWithCall(CI, "logf", "log", "logl");
507 break;
508 }
509 case Intrinsic::log2: {
510 ReplaceFPIntrinsicWithCall(CI, "log2f", "log2", "log2l");
511 break;
512 }
513 case Intrinsic::log10: {
514 ReplaceFPIntrinsicWithCall(CI, "log10f", "log10", "log10l");
515 break;
516 }
517 case Intrinsic::exp: {
518 ReplaceFPIntrinsicWithCall(CI, "expf", "exp", "expl");
519 break;
520 }
521 case Intrinsic::exp2: {
522 ReplaceFPIntrinsicWithCall(CI, "exp2f", "exp2", "exp2l");
523 break;
524 }
525 case Intrinsic::pow: {
526 ReplaceFPIntrinsicWithCall(CI, "powf", "pow", "powl");
527 break;
528 }
529 case Intrinsic::flt_rounds:
530 // Lower to "round to the nearest"
531 if (!CI->getType()->isVoidTy())
532 CI->replaceAllUsesWith(ConstantInt::get(CI->getType(), 1));
533 break;
534 case Intrinsic::invariant_start:
535 case Intrinsic::lifetime_start:
536 // Discard region information.
537 CI->replaceAllUsesWith(UndefValue::get(CI->getType()));
538 break;
539 case Intrinsic::invariant_end:
540 case Intrinsic::lifetime_end:
541 // Discard region information.
542 break;
543 }
544
545 assert(CI->use_empty() &&
546 "Lowering should have eliminated any uses of the intrinsic call!");
547 CI->eraseFromParent();
548 }
549
LowerToByteSwap(CallInst * CI)550 bool IntrinsicLowering::LowerToByteSwap(CallInst *CI) {
551 // Verify this is a simple bswap.
552 if (CI->getNumArgOperands() != 1 ||
553 CI->getType() != CI->getArgOperand(0)->getType() ||
554 !CI->getType()->isIntegerTy())
555 return false;
556
557 IntegerType *Ty = dyn_cast<IntegerType>(CI->getType());
558 if (!Ty)
559 return false;
560
561 // Okay, we can do this xform, do so now.
562 Module *M = CI->getParent()->getParent()->getParent();
563 Constant *Int = Intrinsic::getDeclaration(M, Intrinsic::bswap, Ty);
564
565 Value *Op = CI->getArgOperand(0);
566 Op = CallInst::Create(Int, Op, CI->getName(), CI);
567
568 CI->replaceAllUsesWith(Op);
569 CI->eraseFromParent();
570 return true;
571 }
572