xref: /llvm-project/llvm/lib/Target/ARM/ARMLegalizerInfo.cpp (revision 2ae8bee8f11f8d5cc26cf6b4bb71001706ca0104)
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/GlobalISel/MachineIRBuilder.h"
18 #include "llvm/CodeGen/LowLevelTypeUtils.h"
19 #include "llvm/CodeGen/MachineRegisterInfo.h"
20 #include "llvm/CodeGen/TargetOpcodes.h"
21 #include "llvm/CodeGen/ValueTypes.h"
22 #include "llvm/IR/DerivedTypes.h"
23 #include "llvm/IR/Type.h"
24 
25 using namespace llvm;
26 using namespace LegalizeActions;
27 
28 static bool AEABI(const ARMSubtarget &ST) {
29   return ST.isTargetAEABI() || ST.isTargetGNUAEABI() || ST.isTargetMuslAEABI();
30 }
31 
32 ARMLegalizerInfo::ARMLegalizerInfo(const ARMSubtarget &ST) {
33   using namespace TargetOpcode;
34 
35   const LLT p0 = LLT::pointer(0, 32);
36 
37   const LLT s1 = LLT::scalar(1);
38   const LLT s8 = LLT::scalar(8);
39   const LLT s16 = LLT::scalar(16);
40   const LLT s32 = LLT::scalar(32);
41   const LLT s64 = LLT::scalar(64);
42 
43   auto &LegacyInfo = getLegacyLegalizerInfo();
44   if (ST.isThumb1Only()) {
45     // Thumb1 is not supported yet.
46     LegacyInfo.computeTables();
47     verify(*ST.getInstrInfo());
48     return;
49   }
50 
51   getActionDefinitionsBuilder({G_SEXT, G_ZEXT, G_ANYEXT})
52       .legalForCartesianProduct({s8, s16, s32}, {s1, s8, s16});
53 
54   getActionDefinitionsBuilder(G_SEXT_INREG).lower();
55 
56   getActionDefinitionsBuilder({G_MUL, G_AND, G_OR, G_XOR})
57       .legalFor({s32})
58       .clampScalar(0, s32, s32);
59 
60   if (ST.hasNEON())
61     getActionDefinitionsBuilder({G_ADD, G_SUB})
62         .legalFor({s32, s64})
63         .minScalar(0, s32);
64   else
65     getActionDefinitionsBuilder({G_ADD, G_SUB})
66         .legalFor({s32})
67         .minScalar(0, s32);
68 
69   getActionDefinitionsBuilder({G_ASHR, G_LSHR, G_SHL})
70     .legalFor({{s32, s32}})
71     .minScalar(0, s32)
72     .clampScalar(1, s32, s32);
73 
74   bool HasHWDivide = (!ST.isThumb() && ST.hasDivideInARMMode()) ||
75                      (ST.isThumb() && ST.hasDivideInThumbMode());
76   if (HasHWDivide)
77     getActionDefinitionsBuilder({G_SDIV, G_UDIV})
78         .legalFor({s32})
79         .clampScalar(0, s32, s32);
80   else
81     getActionDefinitionsBuilder({G_SDIV, G_UDIV})
82         .libcallFor({s32})
83         .clampScalar(0, s32, s32);
84 
85   auto &REMBuilder =
86       getActionDefinitionsBuilder({G_SREM, G_UREM}).minScalar(0, s32);
87   if (HasHWDivide)
88     REMBuilder.lowerFor({s32});
89   else if (AEABI(ST))
90     REMBuilder.customFor({s32});
91   else
92     REMBuilder.libcallFor({s32});
93 
94   getActionDefinitionsBuilder(G_INTTOPTR)
95       .legalFor({{p0, s32}})
96       .minScalar(1, s32);
97   getActionDefinitionsBuilder(G_PTRTOINT)
98       .legalFor({{s32, p0}})
99       .minScalar(0, s32);
100 
101   getActionDefinitionsBuilder(G_CONSTANT)
102       .legalFor({s32, p0})
103       .clampScalar(0, s32, s32);
104 
105   getActionDefinitionsBuilder(G_ICMP)
106       .legalForCartesianProduct({s1}, {s32, p0})
107       .minScalar(1, s32);
108 
109   getActionDefinitionsBuilder(G_SELECT)
110       .legalForCartesianProduct({s32, p0}, {s1})
111       .minScalar(0, s32);
112 
113   // We're keeping these builders around because we'll want to add support for
114   // floating point to them.
115   auto &LoadStoreBuilder = getActionDefinitionsBuilder({G_LOAD, G_STORE})
116                                .legalForTypesWithMemDesc({{s8, p0, s8, 8},
117                                                           {s16, p0, s16, 8},
118                                                           {s32, p0, s32, 8},
119                                                           {p0, p0, p0, 8}})
120                                .unsupportedIfMemSizeNotPow2();
121 
122   getActionDefinitionsBuilder(G_FRAME_INDEX).legalFor({p0});
123   getActionDefinitionsBuilder(G_GLOBAL_VALUE).legalFor({p0});
124 
125   auto &PhiBuilder =
126       getActionDefinitionsBuilder(G_PHI)
127           .legalFor({s32, p0})
128           .minScalar(0, s32);
129 
130   getActionDefinitionsBuilder(G_PTR_ADD)
131       .legalFor({{p0, s32}})
132       .minScalar(1, s32);
133 
134   getActionDefinitionsBuilder(G_BRCOND).legalFor({s1});
135 
136   if (!ST.useSoftFloat() && ST.hasVFP2Base()) {
137     getActionDefinitionsBuilder(
138         {G_FADD, G_FSUB, G_FMUL, G_FDIV, G_FCONSTANT, G_FNEG})
139         .legalFor({s32, s64});
140 
141     LoadStoreBuilder
142         .legalForTypesWithMemDesc({{s64, p0, s64, 32}})
143         .maxScalar(0, s32);
144     PhiBuilder.legalFor({s64});
145 
146     getActionDefinitionsBuilder(G_FCMP).legalForCartesianProduct({s1},
147                                                                  {s32, s64});
148 
149     getActionDefinitionsBuilder(G_MERGE_VALUES).legalFor({{s64, s32}});
150     getActionDefinitionsBuilder(G_UNMERGE_VALUES).legalFor({{s32, s64}});
151 
152     getActionDefinitionsBuilder(G_FPEXT).legalFor({{s64, s32}});
153     getActionDefinitionsBuilder(G_FPTRUNC).legalFor({{s32, s64}});
154 
155     getActionDefinitionsBuilder({G_FPTOSI, G_FPTOUI})
156         .legalForCartesianProduct({s32}, {s32, s64});
157     getActionDefinitionsBuilder({G_SITOFP, G_UITOFP})
158         .legalForCartesianProduct({s32, s64}, {s32});
159 
160     getActionDefinitionsBuilder({G_GET_FPENV, G_SET_FPENV}).legalFor({s32});
161     getActionDefinitionsBuilder(G_RESET_FPENV).alwaysLegal();
162   } else {
163     getActionDefinitionsBuilder({G_FADD, G_FSUB, G_FMUL, G_FDIV})
164         .libcallFor({s32, s64});
165 
166     LoadStoreBuilder.maxScalar(0, s32);
167 
168     getActionDefinitionsBuilder(G_FNEG).lowerFor({s32, s64});
169 
170     getActionDefinitionsBuilder(G_FCONSTANT).customFor({s32, s64});
171 
172     getActionDefinitionsBuilder(G_FCMP).customForCartesianProduct({s1},
173                                                                   {s32, s64});
174 
175     if (AEABI(ST))
176       setFCmpLibcallsAEABI();
177     else
178       setFCmpLibcallsGNU();
179 
180     getActionDefinitionsBuilder(G_FPEXT).libcallFor({{s64, s32}});
181     getActionDefinitionsBuilder(G_FPTRUNC).libcallFor({{s32, s64}});
182 
183     getActionDefinitionsBuilder({G_FPTOSI, G_FPTOUI})
184         .libcallForCartesianProduct({s32}, {s32, s64});
185     getActionDefinitionsBuilder({G_SITOFP, G_UITOFP})
186         .libcallForCartesianProduct({s32, s64}, {s32});
187 
188     getActionDefinitionsBuilder({G_GET_FPENV, G_SET_FPENV, G_RESET_FPENV})
189         .libcall();
190   }
191 
192   // Just expand whatever loads and stores are left.
193   LoadStoreBuilder.lower();
194 
195   if (!ST.useSoftFloat() && ST.hasVFP4Base())
196     getActionDefinitionsBuilder(G_FMA).legalFor({s32, s64});
197   else
198     getActionDefinitionsBuilder(G_FMA).libcallFor({s32, s64});
199 
200   getActionDefinitionsBuilder({G_FREM, G_FPOW}).libcallFor({s32, s64});
201 
202   if (ST.hasV5TOps()) {
203     getActionDefinitionsBuilder(G_CTLZ)
204         .legalFor({s32, s32})
205         .clampScalar(1, s32, s32)
206         .clampScalar(0, s32, s32);
207     getActionDefinitionsBuilder(G_CTLZ_ZERO_UNDEF)
208         .lowerFor({s32, s32})
209         .clampScalar(1, s32, s32)
210         .clampScalar(0, s32, s32);
211   } else {
212     getActionDefinitionsBuilder(G_CTLZ_ZERO_UNDEF)
213         .libcallFor({s32, s32})
214         .clampScalar(1, s32, s32)
215         .clampScalar(0, s32, s32);
216     getActionDefinitionsBuilder(G_CTLZ)
217         .lowerFor({s32, s32})
218         .clampScalar(1, s32, s32)
219         .clampScalar(0, s32, s32);
220   }
221 
222   LegacyInfo.computeTables();
223   verify(*ST.getInstrInfo());
224 }
225 
226 void ARMLegalizerInfo::setFCmpLibcallsAEABI() {
227   // FCMP_TRUE and FCMP_FALSE don't need libcalls, they should be
228   // default-initialized.
229   FCmp32Libcalls.resize(CmpInst::LAST_FCMP_PREDICATE + 1);
230   FCmp32Libcalls[CmpInst::FCMP_OEQ] = {
231       {RTLIB::OEQ_F32, CmpInst::BAD_ICMP_PREDICATE}};
232   FCmp32Libcalls[CmpInst::FCMP_OGE] = {
233       {RTLIB::OGE_F32, CmpInst::BAD_ICMP_PREDICATE}};
234   FCmp32Libcalls[CmpInst::FCMP_OGT] = {
235       {RTLIB::OGT_F32, CmpInst::BAD_ICMP_PREDICATE}};
236   FCmp32Libcalls[CmpInst::FCMP_OLE] = {
237       {RTLIB::OLE_F32, CmpInst::BAD_ICMP_PREDICATE}};
238   FCmp32Libcalls[CmpInst::FCMP_OLT] = {
239       {RTLIB::OLT_F32, CmpInst::BAD_ICMP_PREDICATE}};
240   FCmp32Libcalls[CmpInst::FCMP_ORD] = {{RTLIB::UO_F32, CmpInst::ICMP_EQ}};
241   FCmp32Libcalls[CmpInst::FCMP_UGE] = {{RTLIB::OLT_F32, CmpInst::ICMP_EQ}};
242   FCmp32Libcalls[CmpInst::FCMP_UGT] = {{RTLIB::OLE_F32, CmpInst::ICMP_EQ}};
243   FCmp32Libcalls[CmpInst::FCMP_ULE] = {{RTLIB::OGT_F32, CmpInst::ICMP_EQ}};
244   FCmp32Libcalls[CmpInst::FCMP_ULT] = {{RTLIB::OGE_F32, CmpInst::ICMP_EQ}};
245   FCmp32Libcalls[CmpInst::FCMP_UNE] = {{RTLIB::UNE_F32, CmpInst::ICMP_EQ}};
246   FCmp32Libcalls[CmpInst::FCMP_UNO] = {
247       {RTLIB::UO_F32, CmpInst::BAD_ICMP_PREDICATE}};
248   FCmp32Libcalls[CmpInst::FCMP_ONE] = {
249       {RTLIB::OGT_F32, CmpInst::BAD_ICMP_PREDICATE},
250       {RTLIB::OLT_F32, CmpInst::BAD_ICMP_PREDICATE}};
251   FCmp32Libcalls[CmpInst::FCMP_UEQ] = {
252       {RTLIB::OEQ_F32, CmpInst::BAD_ICMP_PREDICATE},
253       {RTLIB::UO_F32, CmpInst::BAD_ICMP_PREDICATE}};
254 
255   FCmp64Libcalls.resize(CmpInst::LAST_FCMP_PREDICATE + 1);
256   FCmp64Libcalls[CmpInst::FCMP_OEQ] = {
257       {RTLIB::OEQ_F64, CmpInst::BAD_ICMP_PREDICATE}};
258   FCmp64Libcalls[CmpInst::FCMP_OGE] = {
259       {RTLIB::OGE_F64, CmpInst::BAD_ICMP_PREDICATE}};
260   FCmp64Libcalls[CmpInst::FCMP_OGT] = {
261       {RTLIB::OGT_F64, CmpInst::BAD_ICMP_PREDICATE}};
262   FCmp64Libcalls[CmpInst::FCMP_OLE] = {
263       {RTLIB::OLE_F64, CmpInst::BAD_ICMP_PREDICATE}};
264   FCmp64Libcalls[CmpInst::FCMP_OLT] = {
265       {RTLIB::OLT_F64, CmpInst::BAD_ICMP_PREDICATE}};
266   FCmp64Libcalls[CmpInst::FCMP_ORD] = {{RTLIB::UO_F64, CmpInst::ICMP_EQ}};
267   FCmp64Libcalls[CmpInst::FCMP_UGE] = {{RTLIB::OLT_F64, CmpInst::ICMP_EQ}};
268   FCmp64Libcalls[CmpInst::FCMP_UGT] = {{RTLIB::OLE_F64, CmpInst::ICMP_EQ}};
269   FCmp64Libcalls[CmpInst::FCMP_ULE] = {{RTLIB::OGT_F64, CmpInst::ICMP_EQ}};
270   FCmp64Libcalls[CmpInst::FCMP_ULT] = {{RTLIB::OGE_F64, CmpInst::ICMP_EQ}};
271   FCmp64Libcalls[CmpInst::FCMP_UNE] = {{RTLIB::UNE_F64, CmpInst::ICMP_EQ}};
272   FCmp64Libcalls[CmpInst::FCMP_UNO] = {
273       {RTLIB::UO_F64, CmpInst::BAD_ICMP_PREDICATE}};
274   FCmp64Libcalls[CmpInst::FCMP_ONE] = {
275       {RTLIB::OGT_F64, CmpInst::BAD_ICMP_PREDICATE},
276       {RTLIB::OLT_F64, CmpInst::BAD_ICMP_PREDICATE}};
277   FCmp64Libcalls[CmpInst::FCMP_UEQ] = {
278       {RTLIB::OEQ_F64, CmpInst::BAD_ICMP_PREDICATE},
279       {RTLIB::UO_F64, CmpInst::BAD_ICMP_PREDICATE}};
280 }
281 
282 void ARMLegalizerInfo::setFCmpLibcallsGNU() {
283   // FCMP_TRUE and FCMP_FALSE don't need libcalls, they should be
284   // default-initialized.
285   FCmp32Libcalls.resize(CmpInst::LAST_FCMP_PREDICATE + 1);
286   FCmp32Libcalls[CmpInst::FCMP_OEQ] = {{RTLIB::OEQ_F32, CmpInst::ICMP_EQ}};
287   FCmp32Libcalls[CmpInst::FCMP_OGE] = {{RTLIB::OGE_F32, CmpInst::ICMP_SGE}};
288   FCmp32Libcalls[CmpInst::FCMP_OGT] = {{RTLIB::OGT_F32, CmpInst::ICMP_SGT}};
289   FCmp32Libcalls[CmpInst::FCMP_OLE] = {{RTLIB::OLE_F32, CmpInst::ICMP_SLE}};
290   FCmp32Libcalls[CmpInst::FCMP_OLT] = {{RTLIB::OLT_F32, CmpInst::ICMP_SLT}};
291   FCmp32Libcalls[CmpInst::FCMP_ORD] = {{RTLIB::UO_F32, CmpInst::ICMP_EQ}};
292   FCmp32Libcalls[CmpInst::FCMP_UGE] = {{RTLIB::OLT_F32, CmpInst::ICMP_SGE}};
293   FCmp32Libcalls[CmpInst::FCMP_UGT] = {{RTLIB::OLE_F32, CmpInst::ICMP_SGT}};
294   FCmp32Libcalls[CmpInst::FCMP_ULE] = {{RTLIB::OGT_F32, CmpInst::ICMP_SLE}};
295   FCmp32Libcalls[CmpInst::FCMP_ULT] = {{RTLIB::OGE_F32, CmpInst::ICMP_SLT}};
296   FCmp32Libcalls[CmpInst::FCMP_UNE] = {{RTLIB::UNE_F32, CmpInst::ICMP_NE}};
297   FCmp32Libcalls[CmpInst::FCMP_UNO] = {{RTLIB::UO_F32, CmpInst::ICMP_NE}};
298   FCmp32Libcalls[CmpInst::FCMP_ONE] = {{RTLIB::OGT_F32, CmpInst::ICMP_SGT},
299                                        {RTLIB::OLT_F32, CmpInst::ICMP_SLT}};
300   FCmp32Libcalls[CmpInst::FCMP_UEQ] = {{RTLIB::OEQ_F32, CmpInst::ICMP_EQ},
301                                        {RTLIB::UO_F32, CmpInst::ICMP_NE}};
302 
303   FCmp64Libcalls.resize(CmpInst::LAST_FCMP_PREDICATE + 1);
304   FCmp64Libcalls[CmpInst::FCMP_OEQ] = {{RTLIB::OEQ_F64, CmpInst::ICMP_EQ}};
305   FCmp64Libcalls[CmpInst::FCMP_OGE] = {{RTLIB::OGE_F64, CmpInst::ICMP_SGE}};
306   FCmp64Libcalls[CmpInst::FCMP_OGT] = {{RTLIB::OGT_F64, CmpInst::ICMP_SGT}};
307   FCmp64Libcalls[CmpInst::FCMP_OLE] = {{RTLIB::OLE_F64, CmpInst::ICMP_SLE}};
308   FCmp64Libcalls[CmpInst::FCMP_OLT] = {{RTLIB::OLT_F64, CmpInst::ICMP_SLT}};
309   FCmp64Libcalls[CmpInst::FCMP_ORD] = {{RTLIB::UO_F64, CmpInst::ICMP_EQ}};
310   FCmp64Libcalls[CmpInst::FCMP_UGE] = {{RTLIB::OLT_F64, CmpInst::ICMP_SGE}};
311   FCmp64Libcalls[CmpInst::FCMP_UGT] = {{RTLIB::OLE_F64, CmpInst::ICMP_SGT}};
312   FCmp64Libcalls[CmpInst::FCMP_ULE] = {{RTLIB::OGT_F64, CmpInst::ICMP_SLE}};
313   FCmp64Libcalls[CmpInst::FCMP_ULT] = {{RTLIB::OGE_F64, CmpInst::ICMP_SLT}};
314   FCmp64Libcalls[CmpInst::FCMP_UNE] = {{RTLIB::UNE_F64, CmpInst::ICMP_NE}};
315   FCmp64Libcalls[CmpInst::FCMP_UNO] = {{RTLIB::UO_F64, CmpInst::ICMP_NE}};
316   FCmp64Libcalls[CmpInst::FCMP_ONE] = {{RTLIB::OGT_F64, CmpInst::ICMP_SGT},
317                                        {RTLIB::OLT_F64, CmpInst::ICMP_SLT}};
318   FCmp64Libcalls[CmpInst::FCMP_UEQ] = {{RTLIB::OEQ_F64, CmpInst::ICMP_EQ},
319                                        {RTLIB::UO_F64, CmpInst::ICMP_NE}};
320 }
321 
322 ARMLegalizerInfo::FCmpLibcallsList
323 ARMLegalizerInfo::getFCmpLibcalls(CmpInst::Predicate Predicate,
324                                   unsigned Size) const {
325   assert(CmpInst::isFPPredicate(Predicate) && "Unsupported FCmp predicate");
326   if (Size == 32)
327     return FCmp32Libcalls[Predicate];
328   if (Size == 64)
329     return FCmp64Libcalls[Predicate];
330   llvm_unreachable("Unsupported size for FCmp predicate");
331 }
332 
333 bool ARMLegalizerInfo::legalizeCustom(LegalizerHelper &Helper, MachineInstr &MI,
334                                       LostDebugLocObserver &LocObserver) const {
335   using namespace TargetOpcode;
336 
337   MachineIRBuilder &MIRBuilder = Helper.MIRBuilder;
338   MachineRegisterInfo &MRI = *MIRBuilder.getMRI();
339   LLVMContext &Ctx = MIRBuilder.getMF().getFunction().getContext();
340 
341   switch (MI.getOpcode()) {
342   default:
343     return false;
344   case G_SREM:
345   case G_UREM: {
346     Register OriginalResult = MI.getOperand(0).getReg();
347     auto Size = MRI.getType(OriginalResult).getSizeInBits();
348     if (Size != 32)
349       return false;
350 
351     auto Libcall =
352         MI.getOpcode() == G_SREM ? RTLIB::SDIVREM_I32 : RTLIB::UDIVREM_I32;
353 
354     // Our divmod libcalls return a struct containing the quotient and the
355     // remainder. Create a new, unused register for the quotient and use the
356     // destination of the original instruction for the remainder.
357     Type *ArgTy = Type::getInt32Ty(Ctx);
358     StructType *RetTy = StructType::get(Ctx, {ArgTy, ArgTy}, /* Packed */ true);
359     Register RetRegs[] = {MRI.createGenericVirtualRegister(LLT::scalar(32)),
360                           OriginalResult};
361     auto Status = createLibcall(MIRBuilder, Libcall, {RetRegs, RetTy, 0},
362                                 {{MI.getOperand(1).getReg(), ArgTy, 0},
363                                  {MI.getOperand(2).getReg(), ArgTy, 0}},
364                                 LocObserver, &MI);
365     if (Status != LegalizerHelper::Legalized)
366       return false;
367     break;
368   }
369   case G_FCMP: {
370     assert(MRI.getType(MI.getOperand(2).getReg()) ==
371                MRI.getType(MI.getOperand(3).getReg()) &&
372            "Mismatched operands for G_FCMP");
373     auto OpSize = MRI.getType(MI.getOperand(2).getReg()).getSizeInBits();
374 
375     auto OriginalResult = MI.getOperand(0).getReg();
376     auto Predicate =
377         static_cast<CmpInst::Predicate>(MI.getOperand(1).getPredicate());
378     auto Libcalls = getFCmpLibcalls(Predicate, OpSize);
379 
380     if (Libcalls.empty()) {
381       assert((Predicate == CmpInst::FCMP_TRUE ||
382               Predicate == CmpInst::FCMP_FALSE) &&
383              "Predicate needs libcalls, but none specified");
384       MIRBuilder.buildConstant(OriginalResult,
385                                Predicate == CmpInst::FCMP_TRUE ? 1 : 0);
386       MI.eraseFromParent();
387       return true;
388     }
389 
390     assert((OpSize == 32 || OpSize == 64) && "Unsupported operand size");
391     auto *ArgTy = OpSize == 32 ? Type::getFloatTy(Ctx) : Type::getDoubleTy(Ctx);
392     auto *RetTy = Type::getInt32Ty(Ctx);
393 
394     SmallVector<Register, 2> Results;
395     for (auto Libcall : Libcalls) {
396       auto LibcallResult = MRI.createGenericVirtualRegister(LLT::scalar(32));
397       auto Status = createLibcall(MIRBuilder, Libcall.LibcallID,
398                                   {LibcallResult, RetTy, 0},
399                                   {{MI.getOperand(2).getReg(), ArgTy, 0},
400                                    {MI.getOperand(3).getReg(), ArgTy, 0}},
401                                   LocObserver, &MI);
402 
403       if (Status != LegalizerHelper::Legalized)
404         return false;
405 
406       auto ProcessedResult =
407           Libcalls.size() == 1
408               ? OriginalResult
409               : MRI.createGenericVirtualRegister(MRI.getType(OriginalResult));
410 
411       // We have a result, but we need to transform it into a proper 1-bit 0 or
412       // 1, taking into account the different peculiarities of the values
413       // returned by the comparison functions.
414       CmpInst::Predicate ResultPred = Libcall.Predicate;
415       if (ResultPred == CmpInst::BAD_ICMP_PREDICATE) {
416         // We have a nice 0 or 1, and we just need to truncate it back to 1 bit
417         // to keep the types consistent.
418         MIRBuilder.buildTrunc(ProcessedResult, LibcallResult);
419       } else {
420         // We need to compare against 0.
421         assert(CmpInst::isIntPredicate(ResultPred) && "Unsupported predicate");
422         auto Zero = MIRBuilder.buildConstant(LLT::scalar(32), 0);
423         MIRBuilder.buildICmp(ResultPred, ProcessedResult, LibcallResult, Zero);
424       }
425       Results.push_back(ProcessedResult);
426     }
427 
428     if (Results.size() != 1) {
429       assert(Results.size() == 2 && "Unexpected number of results");
430       MIRBuilder.buildOr(OriginalResult, Results[0], Results[1]);
431     }
432     break;
433   }
434   case G_FCONSTANT: {
435     // Convert to integer constants, while preserving the binary representation.
436     auto AsInteger =
437         MI.getOperand(1).getFPImm()->getValueAPF().bitcastToAPInt();
438     MIRBuilder.buildConstant(MI.getOperand(0),
439                              *ConstantInt::get(Ctx, AsInteger));
440     break;
441   }
442   }
443 
444   MI.eraseFromParent();
445   return true;
446 }
447