1 //===- ARMLegalizerInfo.cpp --------------------------------------*- C++ -*-==//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 /// \file
9 /// This file implements the targeting of the Machinelegalizer class for ARM.
10 /// \todo This should be generated by TableGen.
11 //===----------------------------------------------------------------------===//
12 
13 #include "ARMLegalizerInfo.h"
14 #include "ARMCallLowering.h"
15 #include "ARMSubtarget.h"
16 #include "llvm/CodeGen/GlobalISel/LegalizerHelper.h"
17 #include "llvm/CodeGen/LowLevelType.h"
18 #include "llvm/CodeGen/MachineRegisterInfo.h"
19 #include "llvm/CodeGen/TargetOpcodes.h"
20 #include "llvm/CodeGen/ValueTypes.h"
21 #include "llvm/IR/DerivedTypes.h"
22 #include "llvm/IR/Type.h"
23 
24 using namespace llvm;
25 using namespace LegalizeActions;
26 
27 /// FIXME: The following static functions are SizeChangeStrategy functions
28 /// that are meant to temporarily mimic the behaviour of the old legalization
29 /// based on doubling/halving non-legal types as closely as possible. This is
30 /// not entirly possible as only legalizing the types that are exactly a power
31 /// of 2 times the size of the legal types would require specifying all those
32 /// sizes explicitly.
33 /// In practice, not specifying those isn't a problem, and the below functions
34 /// should disappear quickly as we add support for legalizing non-power-of-2
35 /// sized types further.
36 static void
37 addAndInterleaveWithUnsupported(LegalizerInfo::SizeAndActionsVec &result,
38                                 const LegalizerInfo::SizeAndActionsVec &v) {
39   for (unsigned i = 0; i < v.size(); ++i) {
40     result.push_back(v[i]);
41     if (i + 1 < v[i].first && i + 1 < v.size() &&
42         v[i + 1].first != v[i].first + 1)
43       result.push_back({v[i].first + 1, Unsupported});
44   }
45 }
46 
47 static LegalizerInfo::SizeAndActionsVec
48 widen_8_16(const LegalizerInfo::SizeAndActionsVec &v) {
49   assert(v.size() >= 1);
50   assert(v[0].first > 17);
51   LegalizerInfo::SizeAndActionsVec result = {{1, Unsupported},
52                                              {8, WidenScalar},
53                                              {9, Unsupported},
54                                              {16, WidenScalar},
55                                              {17, Unsupported}};
56   addAndInterleaveWithUnsupported(result, v);
57   auto Largest = result.back().first;
58   result.push_back({Largest + 1, Unsupported});
59   return result;
60 }
61 
62 static bool AEABI(const ARMSubtarget &ST) {
63   return ST.isTargetAEABI() || ST.isTargetGNUAEABI() || ST.isTargetMuslAEABI();
64 }
65 
66 ARMLegalizerInfo::ARMLegalizerInfo(const ARMSubtarget &ST) {
67   using namespace TargetOpcode;
68 
69   const LLT p0 = LLT::pointer(0, 32);
70 
71   const LLT s1 = LLT::scalar(1);
72   const LLT s8 = LLT::scalar(8);
73   const LLT s16 = LLT::scalar(16);
74   const LLT s32 = LLT::scalar(32);
75   const LLT s64 = LLT::scalar(64);
76 
77   if (ST.isThumb1Only()) {
78     // Thumb1 is not supported yet.
79     computeTables();
80     verify(*ST.getInstrInfo());
81     return;
82   }
83 
84   getActionDefinitionsBuilder({G_SEXT, G_ZEXT, G_ANYEXT})
85       .legalForCartesianProduct({s32}, {s1, s8, s16});
86 
87   getActionDefinitionsBuilder({G_ADD, G_SUB, G_MUL, G_AND, G_OR, G_XOR})
88       .legalFor({s32})
89       .minScalar(0, s32);
90 
91   getActionDefinitionsBuilder({G_ASHR, G_LSHR, G_SHL})
92     .legalFor({{s32, s32}})
93     .minScalar(0, s32)
94     .clampScalar(1, s32, s32);
95 
96   bool HasHWDivide = (!ST.isThumb() && ST.hasDivideInARMMode()) ||
97                      (ST.isThumb() && ST.hasDivideInThumbMode());
98   if (HasHWDivide)
99     getActionDefinitionsBuilder({G_SDIV, G_UDIV})
100         .legalFor({s32})
101         .clampScalar(0, s32, s32);
102   else
103     getActionDefinitionsBuilder({G_SDIV, G_UDIV})
104         .libcallFor({s32})
105         .clampScalar(0, s32, s32);
106 
107   for (unsigned Op : {G_SREM, G_UREM}) {
108     setLegalizeScalarToDifferentSizeStrategy(Op, 0, widen_8_16);
109     if (HasHWDivide)
110       setAction({Op, s32}, Lower);
111     else if (AEABI(ST))
112       setAction({Op, s32}, Custom);
113     else
114       setAction({Op, s32}, Libcall);
115   }
116 
117   getActionDefinitionsBuilder(G_INTTOPTR).legalFor({{p0, s32}});
118   getActionDefinitionsBuilder(G_PTRTOINT).legalFor({{s32, p0}});
119 
120   getActionDefinitionsBuilder(G_CONSTANT)
121       .legalFor({s32, p0})
122       .clampScalar(0, s32, s32);
123 
124   getActionDefinitionsBuilder(G_ICMP)
125       .legalForCartesianProduct({s1}, {s32, p0})
126       .minScalar(1, s32);
127 
128   getActionDefinitionsBuilder(G_SELECT).legalForCartesianProduct({s32, p0},
129                                                                  {s1});
130 
131   // We're keeping these builders around because we'll want to add support for
132   // floating point to them.
133   auto &LoadStoreBuilder = getActionDefinitionsBuilder({G_LOAD, G_STORE})
134                                .legalForTypesWithMemDesc({{s1, p0, 8, 8},
135                                                           {s8, p0, 8, 8},
136                                                           {s16, p0, 16, 8},
137                                                           {s32, p0, 32, 8},
138                                                           {p0, p0, 32, 8}})
139                                .unsupportedIfMemSizeNotPow2();
140 
141   getActionDefinitionsBuilder(G_FRAME_INDEX).legalFor({p0});
142   getActionDefinitionsBuilder(G_GLOBAL_VALUE).legalFor({p0});
143 
144   auto &PhiBuilder =
145       getActionDefinitionsBuilder(G_PHI)
146           .legalFor({s32, p0})
147           .minScalar(0, s32);
148 
149   getActionDefinitionsBuilder(G_GEP).legalFor({{p0, s32}});
150 
151   getActionDefinitionsBuilder(G_BRCOND).legalFor({s1});
152 
153   if (!ST.useSoftFloat() && ST.hasVFP2()) {
154     getActionDefinitionsBuilder(
155         {G_FADD, G_FSUB, G_FMUL, G_FDIV, G_FCONSTANT, G_FNEG})
156         .legalFor({s32, s64});
157 
158     LoadStoreBuilder
159         .legalForTypesWithMemDesc({{s64, p0, 64, 32}})
160         .maxScalar(0, s32);
161     PhiBuilder.legalFor({s64});
162 
163     getActionDefinitionsBuilder(G_FCMP).legalForCartesianProduct({s1},
164                                                                  {s32, s64});
165 
166     getActionDefinitionsBuilder(G_MERGE_VALUES).legalFor({{s64, s32}});
167     getActionDefinitionsBuilder(G_UNMERGE_VALUES).legalFor({{s32, s64}});
168 
169     getActionDefinitionsBuilder(G_FPEXT).legalFor({{s64, s32}});
170     getActionDefinitionsBuilder(G_FPTRUNC).legalFor({{s32, s64}});
171 
172     getActionDefinitionsBuilder({G_FPTOSI, G_FPTOUI})
173         .legalForCartesianProduct({s32}, {s32, s64});
174     getActionDefinitionsBuilder({G_SITOFP, G_UITOFP})
175         .legalForCartesianProduct({s32, s64}, {s32});
176   } else {
177     getActionDefinitionsBuilder({G_FADD, G_FSUB, G_FMUL, G_FDIV})
178         .libcallFor({s32, s64});
179 
180     LoadStoreBuilder.maxScalar(0, s32);
181 
182     for (auto Ty : {s32, s64})
183       setAction({G_FNEG, Ty}, Lower);
184 
185     getActionDefinitionsBuilder(G_FCONSTANT).customFor({s32, s64});
186 
187     getActionDefinitionsBuilder(G_FCMP).customForCartesianProduct({s1},
188                                                                   {s32, s64});
189 
190     if (AEABI(ST))
191       setFCmpLibcallsAEABI();
192     else
193       setFCmpLibcallsGNU();
194 
195     getActionDefinitionsBuilder(G_FPEXT).libcallFor({{s64, s32}});
196     getActionDefinitionsBuilder(G_FPTRUNC).libcallFor({{s32, s64}});
197 
198     getActionDefinitionsBuilder({G_FPTOSI, G_FPTOUI})
199         .libcallForCartesianProduct({s32}, {s32, s64});
200     getActionDefinitionsBuilder({G_SITOFP, G_UITOFP})
201         .libcallForCartesianProduct({s32, s64}, {s32});
202   }
203 
204   if (!ST.useSoftFloat() && ST.hasVFP4())
205     getActionDefinitionsBuilder(G_FMA).legalFor({s32, s64});
206   else
207     getActionDefinitionsBuilder(G_FMA).libcallFor({s32, s64});
208 
209   getActionDefinitionsBuilder({G_FREM, G_FPOW}).libcallFor({s32, s64});
210 
211   if (ST.hasV5TOps()) {
212     getActionDefinitionsBuilder(G_CTLZ)
213         .legalFor({s32, s32})
214         .clampScalar(1, s32, s32)
215         .clampScalar(0, s32, s32);
216     getActionDefinitionsBuilder(G_CTLZ_ZERO_UNDEF)
217         .lowerFor({s32, s32})
218         .clampScalar(1, s32, s32)
219         .clampScalar(0, s32, s32);
220   } else {
221     getActionDefinitionsBuilder(G_CTLZ_ZERO_UNDEF)
222         .libcallFor({s32, s32})
223         .clampScalar(1, s32, s32)
224         .clampScalar(0, s32, s32);
225     getActionDefinitionsBuilder(G_CTLZ)
226         .lowerFor({s32, s32})
227         .clampScalar(1, s32, s32)
228         .clampScalar(0, s32, s32);
229   }
230 
231   computeTables();
232   verify(*ST.getInstrInfo());
233 }
234 
235 void ARMLegalizerInfo::setFCmpLibcallsAEABI() {
236   // FCMP_TRUE and FCMP_FALSE don't need libcalls, they should be
237   // default-initialized.
238   FCmp32Libcalls.resize(CmpInst::LAST_FCMP_PREDICATE + 1);
239   FCmp32Libcalls[CmpInst::FCMP_OEQ] = {
240       {RTLIB::OEQ_F32, CmpInst::BAD_ICMP_PREDICATE}};
241   FCmp32Libcalls[CmpInst::FCMP_OGE] = {
242       {RTLIB::OGE_F32, CmpInst::BAD_ICMP_PREDICATE}};
243   FCmp32Libcalls[CmpInst::FCMP_OGT] = {
244       {RTLIB::OGT_F32, CmpInst::BAD_ICMP_PREDICATE}};
245   FCmp32Libcalls[CmpInst::FCMP_OLE] = {
246       {RTLIB::OLE_F32, CmpInst::BAD_ICMP_PREDICATE}};
247   FCmp32Libcalls[CmpInst::FCMP_OLT] = {
248       {RTLIB::OLT_F32, CmpInst::BAD_ICMP_PREDICATE}};
249   FCmp32Libcalls[CmpInst::FCMP_ORD] = {{RTLIB::O_F32, CmpInst::ICMP_EQ}};
250   FCmp32Libcalls[CmpInst::FCMP_UGE] = {{RTLIB::OLT_F32, CmpInst::ICMP_EQ}};
251   FCmp32Libcalls[CmpInst::FCMP_UGT] = {{RTLIB::OLE_F32, CmpInst::ICMP_EQ}};
252   FCmp32Libcalls[CmpInst::FCMP_ULE] = {{RTLIB::OGT_F32, CmpInst::ICMP_EQ}};
253   FCmp32Libcalls[CmpInst::FCMP_ULT] = {{RTLIB::OGE_F32, CmpInst::ICMP_EQ}};
254   FCmp32Libcalls[CmpInst::FCMP_UNE] = {{RTLIB::UNE_F32, CmpInst::ICMP_EQ}};
255   FCmp32Libcalls[CmpInst::FCMP_UNO] = {
256       {RTLIB::UO_F32, CmpInst::BAD_ICMP_PREDICATE}};
257   FCmp32Libcalls[CmpInst::FCMP_ONE] = {
258       {RTLIB::OGT_F32, CmpInst::BAD_ICMP_PREDICATE},
259       {RTLIB::OLT_F32, CmpInst::BAD_ICMP_PREDICATE}};
260   FCmp32Libcalls[CmpInst::FCMP_UEQ] = {
261       {RTLIB::OEQ_F32, CmpInst::BAD_ICMP_PREDICATE},
262       {RTLIB::UO_F32, CmpInst::BAD_ICMP_PREDICATE}};
263 
264   FCmp64Libcalls.resize(CmpInst::LAST_FCMP_PREDICATE + 1);
265   FCmp64Libcalls[CmpInst::FCMP_OEQ] = {
266       {RTLIB::OEQ_F64, CmpInst::BAD_ICMP_PREDICATE}};
267   FCmp64Libcalls[CmpInst::FCMP_OGE] = {
268       {RTLIB::OGE_F64, CmpInst::BAD_ICMP_PREDICATE}};
269   FCmp64Libcalls[CmpInst::FCMP_OGT] = {
270       {RTLIB::OGT_F64, CmpInst::BAD_ICMP_PREDICATE}};
271   FCmp64Libcalls[CmpInst::FCMP_OLE] = {
272       {RTLIB::OLE_F64, CmpInst::BAD_ICMP_PREDICATE}};
273   FCmp64Libcalls[CmpInst::FCMP_OLT] = {
274       {RTLIB::OLT_F64, CmpInst::BAD_ICMP_PREDICATE}};
275   FCmp64Libcalls[CmpInst::FCMP_ORD] = {{RTLIB::O_F64, CmpInst::ICMP_EQ}};
276   FCmp64Libcalls[CmpInst::FCMP_UGE] = {{RTLIB::OLT_F64, CmpInst::ICMP_EQ}};
277   FCmp64Libcalls[CmpInst::FCMP_UGT] = {{RTLIB::OLE_F64, CmpInst::ICMP_EQ}};
278   FCmp64Libcalls[CmpInst::FCMP_ULE] = {{RTLIB::OGT_F64, CmpInst::ICMP_EQ}};
279   FCmp64Libcalls[CmpInst::FCMP_ULT] = {{RTLIB::OGE_F64, CmpInst::ICMP_EQ}};
280   FCmp64Libcalls[CmpInst::FCMP_UNE] = {{RTLIB::UNE_F64, CmpInst::ICMP_EQ}};
281   FCmp64Libcalls[CmpInst::FCMP_UNO] = {
282       {RTLIB::UO_F64, CmpInst::BAD_ICMP_PREDICATE}};
283   FCmp64Libcalls[CmpInst::FCMP_ONE] = {
284       {RTLIB::OGT_F64, CmpInst::BAD_ICMP_PREDICATE},
285       {RTLIB::OLT_F64, CmpInst::BAD_ICMP_PREDICATE}};
286   FCmp64Libcalls[CmpInst::FCMP_UEQ] = {
287       {RTLIB::OEQ_F64, CmpInst::BAD_ICMP_PREDICATE},
288       {RTLIB::UO_F64, CmpInst::BAD_ICMP_PREDICATE}};
289 }
290 
291 void ARMLegalizerInfo::setFCmpLibcallsGNU() {
292   // FCMP_TRUE and FCMP_FALSE don't need libcalls, they should be
293   // default-initialized.
294   FCmp32Libcalls.resize(CmpInst::LAST_FCMP_PREDICATE + 1);
295   FCmp32Libcalls[CmpInst::FCMP_OEQ] = {{RTLIB::OEQ_F32, CmpInst::ICMP_EQ}};
296   FCmp32Libcalls[CmpInst::FCMP_OGE] = {{RTLIB::OGE_F32, CmpInst::ICMP_SGE}};
297   FCmp32Libcalls[CmpInst::FCMP_OGT] = {{RTLIB::OGT_F32, CmpInst::ICMP_SGT}};
298   FCmp32Libcalls[CmpInst::FCMP_OLE] = {{RTLIB::OLE_F32, CmpInst::ICMP_SLE}};
299   FCmp32Libcalls[CmpInst::FCMP_OLT] = {{RTLIB::OLT_F32, CmpInst::ICMP_SLT}};
300   FCmp32Libcalls[CmpInst::FCMP_ORD] = {{RTLIB::O_F32, CmpInst::ICMP_EQ}};
301   FCmp32Libcalls[CmpInst::FCMP_UGE] = {{RTLIB::OLT_F32, CmpInst::ICMP_SGE}};
302   FCmp32Libcalls[CmpInst::FCMP_UGT] = {{RTLIB::OLE_F32, CmpInst::ICMP_SGT}};
303   FCmp32Libcalls[CmpInst::FCMP_ULE] = {{RTLIB::OGT_F32, CmpInst::ICMP_SLE}};
304   FCmp32Libcalls[CmpInst::FCMP_ULT] = {{RTLIB::OGE_F32, CmpInst::ICMP_SLT}};
305   FCmp32Libcalls[CmpInst::FCMP_UNE] = {{RTLIB::UNE_F32, CmpInst::ICMP_NE}};
306   FCmp32Libcalls[CmpInst::FCMP_UNO] = {{RTLIB::UO_F32, CmpInst::ICMP_NE}};
307   FCmp32Libcalls[CmpInst::FCMP_ONE] = {{RTLIB::OGT_F32, CmpInst::ICMP_SGT},
308                                        {RTLIB::OLT_F32, CmpInst::ICMP_SLT}};
309   FCmp32Libcalls[CmpInst::FCMP_UEQ] = {{RTLIB::OEQ_F32, CmpInst::ICMP_EQ},
310                                        {RTLIB::UO_F32, CmpInst::ICMP_NE}};
311 
312   FCmp64Libcalls.resize(CmpInst::LAST_FCMP_PREDICATE + 1);
313   FCmp64Libcalls[CmpInst::FCMP_OEQ] = {{RTLIB::OEQ_F64, CmpInst::ICMP_EQ}};
314   FCmp64Libcalls[CmpInst::FCMP_OGE] = {{RTLIB::OGE_F64, CmpInst::ICMP_SGE}};
315   FCmp64Libcalls[CmpInst::FCMP_OGT] = {{RTLIB::OGT_F64, CmpInst::ICMP_SGT}};
316   FCmp64Libcalls[CmpInst::FCMP_OLE] = {{RTLIB::OLE_F64, CmpInst::ICMP_SLE}};
317   FCmp64Libcalls[CmpInst::FCMP_OLT] = {{RTLIB::OLT_F64, CmpInst::ICMP_SLT}};
318   FCmp64Libcalls[CmpInst::FCMP_ORD] = {{RTLIB::O_F64, CmpInst::ICMP_EQ}};
319   FCmp64Libcalls[CmpInst::FCMP_UGE] = {{RTLIB::OLT_F64, CmpInst::ICMP_SGE}};
320   FCmp64Libcalls[CmpInst::FCMP_UGT] = {{RTLIB::OLE_F64, CmpInst::ICMP_SGT}};
321   FCmp64Libcalls[CmpInst::FCMP_ULE] = {{RTLIB::OGT_F64, CmpInst::ICMP_SLE}};
322   FCmp64Libcalls[CmpInst::FCMP_ULT] = {{RTLIB::OGE_F64, CmpInst::ICMP_SLT}};
323   FCmp64Libcalls[CmpInst::FCMP_UNE] = {{RTLIB::UNE_F64, CmpInst::ICMP_NE}};
324   FCmp64Libcalls[CmpInst::FCMP_UNO] = {{RTLIB::UO_F64, CmpInst::ICMP_NE}};
325   FCmp64Libcalls[CmpInst::FCMP_ONE] = {{RTLIB::OGT_F64, CmpInst::ICMP_SGT},
326                                        {RTLIB::OLT_F64, CmpInst::ICMP_SLT}};
327   FCmp64Libcalls[CmpInst::FCMP_UEQ] = {{RTLIB::OEQ_F64, CmpInst::ICMP_EQ},
328                                        {RTLIB::UO_F64, CmpInst::ICMP_NE}};
329 }
330 
331 ARMLegalizerInfo::FCmpLibcallsList
332 ARMLegalizerInfo::getFCmpLibcalls(CmpInst::Predicate Predicate,
333                                   unsigned Size) const {
334   assert(CmpInst::isFPPredicate(Predicate) && "Unsupported FCmp predicate");
335   if (Size == 32)
336     return FCmp32Libcalls[Predicate];
337   if (Size == 64)
338     return FCmp64Libcalls[Predicate];
339   llvm_unreachable("Unsupported size for FCmp predicate");
340 }
341 
342 bool ARMLegalizerInfo::legalizeCustom(MachineInstr &MI,
343                                       MachineRegisterInfo &MRI,
344                                       MachineIRBuilder &MIRBuilder,
345                                       GISelChangeObserver &Observer) const {
346   using namespace TargetOpcode;
347 
348   MIRBuilder.setInstr(MI);
349   LLVMContext &Ctx = MIRBuilder.getMF().getFunction().getContext();
350 
351   switch (MI.getOpcode()) {
352   default:
353     return false;
354   case G_SREM:
355   case G_UREM: {
356     unsigned OriginalResult = MI.getOperand(0).getReg();
357     auto Size = MRI.getType(OriginalResult).getSizeInBits();
358     if (Size != 32)
359       return false;
360 
361     auto Libcall =
362         MI.getOpcode() == G_SREM ? RTLIB::SDIVREM_I32 : RTLIB::UDIVREM_I32;
363 
364     // Our divmod libcalls return a struct containing the quotient and the
365     // remainder. We need to create a virtual register for it.
366     Type *ArgTy = Type::getInt32Ty(Ctx);
367     StructType *RetTy = StructType::get(Ctx, {ArgTy, ArgTy}, /* Packed */ true);
368     auto RetVal = MRI.createGenericVirtualRegister(
369         getLLTForType(*RetTy, MIRBuilder.getMF().getDataLayout()));
370 
371     auto Status = createLibcall(MIRBuilder, Libcall, {RetVal, RetTy},
372                                 {{MI.getOperand(1).getReg(), ArgTy},
373                                  {MI.getOperand(2).getReg(), ArgTy}});
374     if (Status != LegalizerHelper::Legalized)
375       return false;
376 
377     // The remainder is the second result of divmod. Split the return value into
378     // a new, unused register for the quotient and the destination of the
379     // original instruction for the remainder.
380     MIRBuilder.buildUnmerge(
381         {MRI.createGenericVirtualRegister(LLT::scalar(32)), OriginalResult},
382         RetVal);
383     break;
384   }
385   case G_FCMP: {
386     assert(MRI.getType(MI.getOperand(2).getReg()) ==
387                MRI.getType(MI.getOperand(3).getReg()) &&
388            "Mismatched operands for G_FCMP");
389     auto OpSize = MRI.getType(MI.getOperand(2).getReg()).getSizeInBits();
390 
391     auto OriginalResult = MI.getOperand(0).getReg();
392     auto Predicate =
393         static_cast<CmpInst::Predicate>(MI.getOperand(1).getPredicate());
394     auto Libcalls = getFCmpLibcalls(Predicate, OpSize);
395 
396     if (Libcalls.empty()) {
397       assert((Predicate == CmpInst::FCMP_TRUE ||
398               Predicate == CmpInst::FCMP_FALSE) &&
399              "Predicate needs libcalls, but none specified");
400       MIRBuilder.buildConstant(OriginalResult,
401                                Predicate == CmpInst::FCMP_TRUE ? 1 : 0);
402       MI.eraseFromParent();
403       return true;
404     }
405 
406     assert((OpSize == 32 || OpSize == 64) && "Unsupported operand size");
407     auto *ArgTy = OpSize == 32 ? Type::getFloatTy(Ctx) : Type::getDoubleTy(Ctx);
408     auto *RetTy = Type::getInt32Ty(Ctx);
409 
410     SmallVector<unsigned, 2> Results;
411     for (auto Libcall : Libcalls) {
412       auto LibcallResult = MRI.createGenericVirtualRegister(LLT::scalar(32));
413       auto Status =
414           createLibcall(MIRBuilder, Libcall.LibcallID, {LibcallResult, RetTy},
415                         {{MI.getOperand(2).getReg(), ArgTy},
416                          {MI.getOperand(3).getReg(), ArgTy}});
417 
418       if (Status != LegalizerHelper::Legalized)
419         return false;
420 
421       auto ProcessedResult =
422           Libcalls.size() == 1
423               ? OriginalResult
424               : MRI.createGenericVirtualRegister(MRI.getType(OriginalResult));
425 
426       // We have a result, but we need to transform it into a proper 1-bit 0 or
427       // 1, taking into account the different peculiarities of the values
428       // returned by the comparison functions.
429       CmpInst::Predicate ResultPred = Libcall.Predicate;
430       if (ResultPred == CmpInst::BAD_ICMP_PREDICATE) {
431         // We have a nice 0 or 1, and we just need to truncate it back to 1 bit
432         // to keep the types consistent.
433         MIRBuilder.buildTrunc(ProcessedResult, LibcallResult);
434       } else {
435         // We need to compare against 0.
436         assert(CmpInst::isIntPredicate(ResultPred) && "Unsupported predicate");
437         auto Zero = MRI.createGenericVirtualRegister(LLT::scalar(32));
438         MIRBuilder.buildConstant(Zero, 0);
439         MIRBuilder.buildICmp(ResultPred, ProcessedResult, LibcallResult, Zero);
440       }
441       Results.push_back(ProcessedResult);
442     }
443 
444     if (Results.size() != 1) {
445       assert(Results.size() == 2 && "Unexpected number of results");
446       MIRBuilder.buildOr(OriginalResult, Results[0], Results[1]);
447     }
448     break;
449   }
450   case G_FCONSTANT: {
451     // Convert to integer constants, while preserving the binary representation.
452     auto AsInteger =
453         MI.getOperand(1).getFPImm()->getValueAPF().bitcastToAPInt();
454     MIRBuilder.buildConstant(MI.getOperand(0).getReg(),
455                              *ConstantInt::get(Ctx, AsInteger));
456     break;
457   }
458   }
459 
460   MI.eraseFromParent();
461   return true;
462 }
463