xref: /llvm-project/llvm/lib/Target/ARM/ARMLegalizerInfo.cpp (revision 0a47fb88847774eacc0ee4d33d734e5c31f9e2ad)
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({s8, s16, 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)
118       .legalFor({{p0, s32}})
119       .minScalar(1, s32);
120   getActionDefinitionsBuilder(G_PTRTOINT)
121       .legalFor({{s32, p0}})
122       .minScalar(0, s32);
123 
124   getActionDefinitionsBuilder(G_CONSTANT)
125       .legalFor({s32, p0})
126       .clampScalar(0, s32, s32);
127 
128   getActionDefinitionsBuilder(G_ICMP)
129       .legalForCartesianProduct({s1}, {s32, p0})
130       .minScalar(1, s32);
131 
132   getActionDefinitionsBuilder(G_SELECT)
133       .legalForCartesianProduct({s32, p0}, {s1})
134       .minScalar(0, s32);
135 
136   // We're keeping these builders around because we'll want to add support for
137   // floating point to them.
138   auto &LoadStoreBuilder = getActionDefinitionsBuilder({G_LOAD, G_STORE})
139                                .legalForTypesWithMemDesc({{s1, p0, 8, 8},
140                                                           {s8, p0, 8, 8},
141                                                           {s16, p0, 16, 8},
142                                                           {s32, p0, 32, 8},
143                                                           {p0, p0, 32, 8}})
144                                .unsupportedIfMemSizeNotPow2();
145 
146   getActionDefinitionsBuilder(G_FRAME_INDEX).legalFor({p0});
147   getActionDefinitionsBuilder(G_GLOBAL_VALUE).legalFor({p0});
148 
149   auto &PhiBuilder =
150       getActionDefinitionsBuilder(G_PHI)
151           .legalFor({s32, p0})
152           .minScalar(0, s32);
153 
154   getActionDefinitionsBuilder(G_GEP)
155       .legalFor({{p0, s32}})
156       .minScalar(1, s32);
157 
158   getActionDefinitionsBuilder(G_BRCOND).legalFor({s1});
159 
160   if (!ST.useSoftFloat() && ST.hasVFP2()) {
161     getActionDefinitionsBuilder(
162         {G_FADD, G_FSUB, G_FMUL, G_FDIV, G_FCONSTANT, G_FNEG})
163         .legalFor({s32, s64});
164 
165     LoadStoreBuilder
166         .legalForTypesWithMemDesc({{s64, p0, 64, 32}})
167         .maxScalar(0, s32);
168     PhiBuilder.legalFor({s64});
169 
170     getActionDefinitionsBuilder(G_FCMP).legalForCartesianProduct({s1},
171                                                                  {s32, s64});
172 
173     getActionDefinitionsBuilder(G_MERGE_VALUES).legalFor({{s64, s32}});
174     getActionDefinitionsBuilder(G_UNMERGE_VALUES).legalFor({{s32, s64}});
175 
176     getActionDefinitionsBuilder(G_FPEXT).legalFor({{s64, s32}});
177     getActionDefinitionsBuilder(G_FPTRUNC).legalFor({{s32, s64}});
178 
179     getActionDefinitionsBuilder({G_FPTOSI, G_FPTOUI})
180         .legalForCartesianProduct({s32}, {s32, s64});
181     getActionDefinitionsBuilder({G_SITOFP, G_UITOFP})
182         .legalForCartesianProduct({s32, s64}, {s32});
183   } else {
184     getActionDefinitionsBuilder({G_FADD, G_FSUB, G_FMUL, G_FDIV})
185         .libcallFor({s32, s64});
186 
187     LoadStoreBuilder.maxScalar(0, s32);
188 
189     for (auto Ty : {s32, s64})
190       setAction({G_FNEG, Ty}, Lower);
191 
192     getActionDefinitionsBuilder(G_FCONSTANT).customFor({s32, s64});
193 
194     getActionDefinitionsBuilder(G_FCMP).customForCartesianProduct({s1},
195                                                                   {s32, s64});
196 
197     if (AEABI(ST))
198       setFCmpLibcallsAEABI();
199     else
200       setFCmpLibcallsGNU();
201 
202     getActionDefinitionsBuilder(G_FPEXT).libcallFor({{s64, s32}});
203     getActionDefinitionsBuilder(G_FPTRUNC).libcallFor({{s32, s64}});
204 
205     getActionDefinitionsBuilder({G_FPTOSI, G_FPTOUI})
206         .libcallForCartesianProduct({s32}, {s32, s64});
207     getActionDefinitionsBuilder({G_SITOFP, G_UITOFP})
208         .libcallForCartesianProduct({s32, s64}, {s32});
209   }
210 
211   if (!ST.useSoftFloat() && ST.hasVFP4())
212     getActionDefinitionsBuilder(G_FMA).legalFor({s32, s64});
213   else
214     getActionDefinitionsBuilder(G_FMA).libcallFor({s32, s64});
215 
216   getActionDefinitionsBuilder({G_FREM, G_FPOW}).libcallFor({s32, s64});
217 
218   if (ST.hasV5TOps()) {
219     getActionDefinitionsBuilder(G_CTLZ)
220         .legalFor({s32, s32})
221         .clampScalar(1, s32, s32)
222         .clampScalar(0, s32, s32);
223     getActionDefinitionsBuilder(G_CTLZ_ZERO_UNDEF)
224         .lowerFor({s32, s32})
225         .clampScalar(1, s32, s32)
226         .clampScalar(0, s32, s32);
227   } else {
228     getActionDefinitionsBuilder(G_CTLZ_ZERO_UNDEF)
229         .libcallFor({s32, s32})
230         .clampScalar(1, s32, s32)
231         .clampScalar(0, s32, s32);
232     getActionDefinitionsBuilder(G_CTLZ)
233         .lowerFor({s32, s32})
234         .clampScalar(1, s32, s32)
235         .clampScalar(0, s32, s32);
236   }
237 
238   computeTables();
239   verify(*ST.getInstrInfo());
240 }
241 
242 void ARMLegalizerInfo::setFCmpLibcallsAEABI() {
243   // FCMP_TRUE and FCMP_FALSE don't need libcalls, they should be
244   // default-initialized.
245   FCmp32Libcalls.resize(CmpInst::LAST_FCMP_PREDICATE + 1);
246   FCmp32Libcalls[CmpInst::FCMP_OEQ] = {
247       {RTLIB::OEQ_F32, CmpInst::BAD_ICMP_PREDICATE}};
248   FCmp32Libcalls[CmpInst::FCMP_OGE] = {
249       {RTLIB::OGE_F32, CmpInst::BAD_ICMP_PREDICATE}};
250   FCmp32Libcalls[CmpInst::FCMP_OGT] = {
251       {RTLIB::OGT_F32, CmpInst::BAD_ICMP_PREDICATE}};
252   FCmp32Libcalls[CmpInst::FCMP_OLE] = {
253       {RTLIB::OLE_F32, CmpInst::BAD_ICMP_PREDICATE}};
254   FCmp32Libcalls[CmpInst::FCMP_OLT] = {
255       {RTLIB::OLT_F32, CmpInst::BAD_ICMP_PREDICATE}};
256   FCmp32Libcalls[CmpInst::FCMP_ORD] = {{RTLIB::O_F32, CmpInst::ICMP_EQ}};
257   FCmp32Libcalls[CmpInst::FCMP_UGE] = {{RTLIB::OLT_F32, CmpInst::ICMP_EQ}};
258   FCmp32Libcalls[CmpInst::FCMP_UGT] = {{RTLIB::OLE_F32, CmpInst::ICMP_EQ}};
259   FCmp32Libcalls[CmpInst::FCMP_ULE] = {{RTLIB::OGT_F32, CmpInst::ICMP_EQ}};
260   FCmp32Libcalls[CmpInst::FCMP_ULT] = {{RTLIB::OGE_F32, CmpInst::ICMP_EQ}};
261   FCmp32Libcalls[CmpInst::FCMP_UNE] = {{RTLIB::UNE_F32, CmpInst::ICMP_EQ}};
262   FCmp32Libcalls[CmpInst::FCMP_UNO] = {
263       {RTLIB::UO_F32, CmpInst::BAD_ICMP_PREDICATE}};
264   FCmp32Libcalls[CmpInst::FCMP_ONE] = {
265       {RTLIB::OGT_F32, CmpInst::BAD_ICMP_PREDICATE},
266       {RTLIB::OLT_F32, CmpInst::BAD_ICMP_PREDICATE}};
267   FCmp32Libcalls[CmpInst::FCMP_UEQ] = {
268       {RTLIB::OEQ_F32, CmpInst::BAD_ICMP_PREDICATE},
269       {RTLIB::UO_F32, CmpInst::BAD_ICMP_PREDICATE}};
270 
271   FCmp64Libcalls.resize(CmpInst::LAST_FCMP_PREDICATE + 1);
272   FCmp64Libcalls[CmpInst::FCMP_OEQ] = {
273       {RTLIB::OEQ_F64, CmpInst::BAD_ICMP_PREDICATE}};
274   FCmp64Libcalls[CmpInst::FCMP_OGE] = {
275       {RTLIB::OGE_F64, CmpInst::BAD_ICMP_PREDICATE}};
276   FCmp64Libcalls[CmpInst::FCMP_OGT] = {
277       {RTLIB::OGT_F64, CmpInst::BAD_ICMP_PREDICATE}};
278   FCmp64Libcalls[CmpInst::FCMP_OLE] = {
279       {RTLIB::OLE_F64, CmpInst::BAD_ICMP_PREDICATE}};
280   FCmp64Libcalls[CmpInst::FCMP_OLT] = {
281       {RTLIB::OLT_F64, CmpInst::BAD_ICMP_PREDICATE}};
282   FCmp64Libcalls[CmpInst::FCMP_ORD] = {{RTLIB::O_F64, CmpInst::ICMP_EQ}};
283   FCmp64Libcalls[CmpInst::FCMP_UGE] = {{RTLIB::OLT_F64, CmpInst::ICMP_EQ}};
284   FCmp64Libcalls[CmpInst::FCMP_UGT] = {{RTLIB::OLE_F64, CmpInst::ICMP_EQ}};
285   FCmp64Libcalls[CmpInst::FCMP_ULE] = {{RTLIB::OGT_F64, CmpInst::ICMP_EQ}};
286   FCmp64Libcalls[CmpInst::FCMP_ULT] = {{RTLIB::OGE_F64, CmpInst::ICMP_EQ}};
287   FCmp64Libcalls[CmpInst::FCMP_UNE] = {{RTLIB::UNE_F64, CmpInst::ICMP_EQ}};
288   FCmp64Libcalls[CmpInst::FCMP_UNO] = {
289       {RTLIB::UO_F64, CmpInst::BAD_ICMP_PREDICATE}};
290   FCmp64Libcalls[CmpInst::FCMP_ONE] = {
291       {RTLIB::OGT_F64, CmpInst::BAD_ICMP_PREDICATE},
292       {RTLIB::OLT_F64, CmpInst::BAD_ICMP_PREDICATE}};
293   FCmp64Libcalls[CmpInst::FCMP_UEQ] = {
294       {RTLIB::OEQ_F64, CmpInst::BAD_ICMP_PREDICATE},
295       {RTLIB::UO_F64, CmpInst::BAD_ICMP_PREDICATE}};
296 }
297 
298 void ARMLegalizerInfo::setFCmpLibcallsGNU() {
299   // FCMP_TRUE and FCMP_FALSE don't need libcalls, they should be
300   // default-initialized.
301   FCmp32Libcalls.resize(CmpInst::LAST_FCMP_PREDICATE + 1);
302   FCmp32Libcalls[CmpInst::FCMP_OEQ] = {{RTLIB::OEQ_F32, CmpInst::ICMP_EQ}};
303   FCmp32Libcalls[CmpInst::FCMP_OGE] = {{RTLIB::OGE_F32, CmpInst::ICMP_SGE}};
304   FCmp32Libcalls[CmpInst::FCMP_OGT] = {{RTLIB::OGT_F32, CmpInst::ICMP_SGT}};
305   FCmp32Libcalls[CmpInst::FCMP_OLE] = {{RTLIB::OLE_F32, CmpInst::ICMP_SLE}};
306   FCmp32Libcalls[CmpInst::FCMP_OLT] = {{RTLIB::OLT_F32, CmpInst::ICMP_SLT}};
307   FCmp32Libcalls[CmpInst::FCMP_ORD] = {{RTLIB::O_F32, CmpInst::ICMP_EQ}};
308   FCmp32Libcalls[CmpInst::FCMP_UGE] = {{RTLIB::OLT_F32, CmpInst::ICMP_SGE}};
309   FCmp32Libcalls[CmpInst::FCMP_UGT] = {{RTLIB::OLE_F32, CmpInst::ICMP_SGT}};
310   FCmp32Libcalls[CmpInst::FCMP_ULE] = {{RTLIB::OGT_F32, CmpInst::ICMP_SLE}};
311   FCmp32Libcalls[CmpInst::FCMP_ULT] = {{RTLIB::OGE_F32, CmpInst::ICMP_SLT}};
312   FCmp32Libcalls[CmpInst::FCMP_UNE] = {{RTLIB::UNE_F32, CmpInst::ICMP_NE}};
313   FCmp32Libcalls[CmpInst::FCMP_UNO] = {{RTLIB::UO_F32, CmpInst::ICMP_NE}};
314   FCmp32Libcalls[CmpInst::FCMP_ONE] = {{RTLIB::OGT_F32, CmpInst::ICMP_SGT},
315                                        {RTLIB::OLT_F32, CmpInst::ICMP_SLT}};
316   FCmp32Libcalls[CmpInst::FCMP_UEQ] = {{RTLIB::OEQ_F32, CmpInst::ICMP_EQ},
317                                        {RTLIB::UO_F32, CmpInst::ICMP_NE}};
318 
319   FCmp64Libcalls.resize(CmpInst::LAST_FCMP_PREDICATE + 1);
320   FCmp64Libcalls[CmpInst::FCMP_OEQ] = {{RTLIB::OEQ_F64, CmpInst::ICMP_EQ}};
321   FCmp64Libcalls[CmpInst::FCMP_OGE] = {{RTLIB::OGE_F64, CmpInst::ICMP_SGE}};
322   FCmp64Libcalls[CmpInst::FCMP_OGT] = {{RTLIB::OGT_F64, CmpInst::ICMP_SGT}};
323   FCmp64Libcalls[CmpInst::FCMP_OLE] = {{RTLIB::OLE_F64, CmpInst::ICMP_SLE}};
324   FCmp64Libcalls[CmpInst::FCMP_OLT] = {{RTLIB::OLT_F64, CmpInst::ICMP_SLT}};
325   FCmp64Libcalls[CmpInst::FCMP_ORD] = {{RTLIB::O_F64, CmpInst::ICMP_EQ}};
326   FCmp64Libcalls[CmpInst::FCMP_UGE] = {{RTLIB::OLT_F64, CmpInst::ICMP_SGE}};
327   FCmp64Libcalls[CmpInst::FCMP_UGT] = {{RTLIB::OLE_F64, CmpInst::ICMP_SGT}};
328   FCmp64Libcalls[CmpInst::FCMP_ULE] = {{RTLIB::OGT_F64, CmpInst::ICMP_SLE}};
329   FCmp64Libcalls[CmpInst::FCMP_ULT] = {{RTLIB::OGE_F64, CmpInst::ICMP_SLT}};
330   FCmp64Libcalls[CmpInst::FCMP_UNE] = {{RTLIB::UNE_F64, CmpInst::ICMP_NE}};
331   FCmp64Libcalls[CmpInst::FCMP_UNO] = {{RTLIB::UO_F64, CmpInst::ICMP_NE}};
332   FCmp64Libcalls[CmpInst::FCMP_ONE] = {{RTLIB::OGT_F64, CmpInst::ICMP_SGT},
333                                        {RTLIB::OLT_F64, CmpInst::ICMP_SLT}};
334   FCmp64Libcalls[CmpInst::FCMP_UEQ] = {{RTLIB::OEQ_F64, CmpInst::ICMP_EQ},
335                                        {RTLIB::UO_F64, CmpInst::ICMP_NE}};
336 }
337 
338 ARMLegalizerInfo::FCmpLibcallsList
339 ARMLegalizerInfo::getFCmpLibcalls(CmpInst::Predicate Predicate,
340                                   unsigned Size) const {
341   assert(CmpInst::isFPPredicate(Predicate) && "Unsupported FCmp predicate");
342   if (Size == 32)
343     return FCmp32Libcalls[Predicate];
344   if (Size == 64)
345     return FCmp64Libcalls[Predicate];
346   llvm_unreachable("Unsupported size for FCmp predicate");
347 }
348 
349 bool ARMLegalizerInfo::legalizeCustom(MachineInstr &MI,
350                                       MachineRegisterInfo &MRI,
351                                       MachineIRBuilder &MIRBuilder,
352                                       GISelChangeObserver &Observer) const {
353   using namespace TargetOpcode;
354 
355   MIRBuilder.setInstr(MI);
356   LLVMContext &Ctx = MIRBuilder.getMF().getFunction().getContext();
357 
358   switch (MI.getOpcode()) {
359   default:
360     return false;
361   case G_SREM:
362   case G_UREM: {
363     unsigned OriginalResult = MI.getOperand(0).getReg();
364     auto Size = MRI.getType(OriginalResult).getSizeInBits();
365     if (Size != 32)
366       return false;
367 
368     auto Libcall =
369         MI.getOpcode() == G_SREM ? RTLIB::SDIVREM_I32 : RTLIB::UDIVREM_I32;
370 
371     // Our divmod libcalls return a struct containing the quotient and the
372     // remainder. We need to create a virtual register for it.
373     Type *ArgTy = Type::getInt32Ty(Ctx);
374     StructType *RetTy = StructType::get(Ctx, {ArgTy, ArgTy}, /* Packed */ true);
375     auto RetVal = MRI.createGenericVirtualRegister(
376         getLLTForType(*RetTy, MIRBuilder.getMF().getDataLayout()));
377 
378     auto Status = createLibcall(MIRBuilder, Libcall, {RetVal, RetTy},
379                                 {{MI.getOperand(1).getReg(), ArgTy},
380                                  {MI.getOperand(2).getReg(), ArgTy}});
381     if (Status != LegalizerHelper::Legalized)
382       return false;
383 
384     // The remainder is the second result of divmod. Split the return value into
385     // a new, unused register for the quotient and the destination of the
386     // original instruction for the remainder.
387     MIRBuilder.buildUnmerge(
388         {MRI.createGenericVirtualRegister(LLT::scalar(32)), OriginalResult},
389         RetVal);
390     break;
391   }
392   case G_FCMP: {
393     assert(MRI.getType(MI.getOperand(2).getReg()) ==
394                MRI.getType(MI.getOperand(3).getReg()) &&
395            "Mismatched operands for G_FCMP");
396     auto OpSize = MRI.getType(MI.getOperand(2).getReg()).getSizeInBits();
397 
398     auto OriginalResult = MI.getOperand(0).getReg();
399     auto Predicate =
400         static_cast<CmpInst::Predicate>(MI.getOperand(1).getPredicate());
401     auto Libcalls = getFCmpLibcalls(Predicate, OpSize);
402 
403     if (Libcalls.empty()) {
404       assert((Predicate == CmpInst::FCMP_TRUE ||
405               Predicate == CmpInst::FCMP_FALSE) &&
406              "Predicate needs libcalls, but none specified");
407       MIRBuilder.buildConstant(OriginalResult,
408                                Predicate == CmpInst::FCMP_TRUE ? 1 : 0);
409       MI.eraseFromParent();
410       return true;
411     }
412 
413     assert((OpSize == 32 || OpSize == 64) && "Unsupported operand size");
414     auto *ArgTy = OpSize == 32 ? Type::getFloatTy(Ctx) : Type::getDoubleTy(Ctx);
415     auto *RetTy = Type::getInt32Ty(Ctx);
416 
417     SmallVector<unsigned, 2> Results;
418     for (auto Libcall : Libcalls) {
419       auto LibcallResult = MRI.createGenericVirtualRegister(LLT::scalar(32));
420       auto Status =
421           createLibcall(MIRBuilder, Libcall.LibcallID, {LibcallResult, RetTy},
422                         {{MI.getOperand(2).getReg(), ArgTy},
423                          {MI.getOperand(3).getReg(), ArgTy}});
424 
425       if (Status != LegalizerHelper::Legalized)
426         return false;
427 
428       auto ProcessedResult =
429           Libcalls.size() == 1
430               ? OriginalResult
431               : MRI.createGenericVirtualRegister(MRI.getType(OriginalResult));
432 
433       // We have a result, but we need to transform it into a proper 1-bit 0 or
434       // 1, taking into account the different peculiarities of the values
435       // returned by the comparison functions.
436       CmpInst::Predicate ResultPred = Libcall.Predicate;
437       if (ResultPred == CmpInst::BAD_ICMP_PREDICATE) {
438         // We have a nice 0 or 1, and we just need to truncate it back to 1 bit
439         // to keep the types consistent.
440         MIRBuilder.buildTrunc(ProcessedResult, LibcallResult);
441       } else {
442         // We need to compare against 0.
443         assert(CmpInst::isIntPredicate(ResultPred) && "Unsupported predicate");
444         auto Zero = MRI.createGenericVirtualRegister(LLT::scalar(32));
445         MIRBuilder.buildConstant(Zero, 0);
446         MIRBuilder.buildICmp(ResultPred, ProcessedResult, LibcallResult, Zero);
447       }
448       Results.push_back(ProcessedResult);
449     }
450 
451     if (Results.size() != 1) {
452       assert(Results.size() == 2 && "Unexpected number of results");
453       MIRBuilder.buildOr(OriginalResult, Results[0], Results[1]);
454     }
455     break;
456   }
457   case G_FCONSTANT: {
458     // Convert to integer constants, while preserving the binary representation.
459     auto AsInteger =
460         MI.getOperand(1).getFPImm()->getValueAPF().bitcastToAPInt();
461     MIRBuilder.buildConstant(MI.getOperand(0).getReg(),
462                              *ConstantInt::get(Ctx, AsInteger));
463     break;
464   }
465   }
466 
467   MI.eraseFromParent();
468   return true;
469 }
470