1 //===- KnownBitsTest.cpp -------------------------------------------===//
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 
9 #include "GISelMITest.h"
10 #include "llvm/CodeGen/GlobalISel/GISelKnownBits.h"
11 #include "llvm/CodeGen/GlobalISel/MachineIRBuilder.h"
12 
13 TEST_F(AArch64GISelMITest, TestKnownBitsCst) {
14   StringRef MIRString = "  %3:_(s8) = G_CONSTANT i8 1\n"
15                         "  %4:_(s8) = COPY %3\n";
16   setUp(MIRString);
17   if (!TM)
18     return;
19   unsigned CopyReg = Copies[Copies.size() - 1];
20   MachineInstr *FinalCopy = MRI->getVRegDef(CopyReg);
21   unsigned SrcReg = FinalCopy->getOperand(1).getReg();
22   unsigned DstReg = FinalCopy->getOperand(0).getReg();
23   GISelKnownBits Info(*MF);
24   KnownBits Res = Info.getKnownBits(SrcReg);
25   EXPECT_EQ((uint64_t)1, Res.One.getZExtValue());
26   EXPECT_EQ((uint64_t)0xfe, Res.Zero.getZExtValue());
27 
28   KnownBits Res2 = Info.getKnownBits(DstReg);
29   EXPECT_EQ(Res.One.getZExtValue(), Res2.One.getZExtValue());
30   EXPECT_EQ(Res.Zero.getZExtValue(), Res2.Zero.getZExtValue());
31 }
32 
33 TEST_F(AArch64GISelMITest, TestKnownBitsCstWithClass) {
34   StringRef MIRString = "  %10:gpr32 = MOVi32imm 1\n"
35                         "  %4:_(s32) = COPY %10\n";
36   setUp(MIRString);
37   if (!TM)
38     return;
39   unsigned CopyReg = Copies[Copies.size() - 1];
40   MachineInstr *FinalCopy = MRI->getVRegDef(CopyReg);
41   unsigned SrcReg = FinalCopy->getOperand(1).getReg();
42   unsigned DstReg = FinalCopy->getOperand(0).getReg();
43   GISelKnownBits Info(*MF);
44   KnownBits Res = Info.getKnownBits(SrcReg);
45   // We can't analyze %3 due to the register class constraint. We will get a
46   // default-constructed KnownBits back.
47   EXPECT_EQ((uint64_t)1, Res.getBitWidth());
48   EXPECT_EQ((uint64_t)0, Res.One.getZExtValue());
49   EXPECT_EQ((uint64_t)0, Res.Zero.getZExtValue());
50 
51   KnownBits Res2 = Info.getKnownBits(DstReg);
52   // We still don't know the values due to the register class constraint but %4
53   // did reveal the size of %3.
54   EXPECT_EQ((uint64_t)32, Res2.getBitWidth());
55   EXPECT_EQ(Res.One.getZExtValue(), Res2.One.getZExtValue());
56   EXPECT_EQ(Res.Zero.getZExtValue(), Res2.Zero.getZExtValue());
57 }
58 
59 // Check that we are able to track bits through PHIs
60 // and get the intersections of everything we know on each operand.
61 TEST_F(AArch64GISelMITest, TestKnownBitsCstPHI) {
62   StringRef MIRString = "  bb.10:\n"
63                         "  %10:_(s8) = G_CONSTANT i8 3\n"
64                         "  %11:_(s1) = G_IMPLICIT_DEF\n"
65                         "  G_BRCOND %11(s1), %bb.11\n"
66                         "  G_BR %bb.12\n"
67                         "\n"
68                         "  bb.11:\n"
69                         "  %12:_(s8) = G_CONSTANT i8 2\n"
70                         "  G_BR %bb.12\n"
71                         "\n"
72                         "  bb.12:\n"
73                         "  %13:_(s8) = PHI %10(s8), %bb.10, %12(s8), %bb.11\n"
74                         "  %14:_(s8) = COPY %13\n";
75   setUp(MIRString);
76   if (!TM)
77     return;
78   Register CopyReg = Copies[Copies.size() - 1];
79   MachineInstr *FinalCopy = MRI->getVRegDef(CopyReg);
80   Register SrcReg = FinalCopy->getOperand(1).getReg();
81   Register DstReg = FinalCopy->getOperand(0).getReg();
82   GISelKnownBits Info(*MF);
83   KnownBits Res = Info.getKnownBits(SrcReg);
84   EXPECT_EQ((uint64_t)2, Res.One.getZExtValue());
85   EXPECT_EQ((uint64_t)0xfc, Res.Zero.getZExtValue());
86 
87   KnownBits Res2 = Info.getKnownBits(DstReg);
88   EXPECT_EQ(Res.One.getZExtValue(), Res2.One.getZExtValue());
89   EXPECT_EQ(Res.Zero.getZExtValue(), Res2.Zero.getZExtValue());
90 }
91 
92 // Check that we report we know nothing when we hit a
93 // non-generic register.
94 // Note: this could be improved though!
95 TEST_F(AArch64GISelMITest, TestKnownBitsCstPHIToNonGenericReg) {
96   StringRef MIRString = "  bb.10:\n"
97                         "  %10:gpr32 = MOVi32imm 3\n"
98                         "  %11:_(s1) = G_IMPLICIT_DEF\n"
99                         "  G_BRCOND %11(s1), %bb.11\n"
100                         "  G_BR %bb.12\n"
101                         "\n"
102                         "  bb.11:\n"
103                         "  %12:_(s8) = G_CONSTANT i8 2\n"
104                         "  G_BR %bb.12\n"
105                         "\n"
106                         "  bb.12:\n"
107                         "  %13:_(s8) = PHI %10, %bb.10, %12(s8), %bb.11\n"
108                         "  %14:_(s8) = COPY %13\n";
109   setUp(MIRString);
110   if (!TM)
111     return;
112   Register CopyReg = Copies[Copies.size() - 1];
113   MachineInstr *FinalCopy = MRI->getVRegDef(CopyReg);
114   Register SrcReg = FinalCopy->getOperand(1).getReg();
115   Register DstReg = FinalCopy->getOperand(0).getReg();
116   GISelKnownBits Info(*MF);
117   KnownBits Res = Info.getKnownBits(SrcReg);
118   EXPECT_EQ((uint64_t)0, Res.One.getZExtValue());
119   EXPECT_EQ((uint64_t)0, Res.Zero.getZExtValue());
120 
121   KnownBits Res2 = Info.getKnownBits(DstReg);
122   EXPECT_EQ(Res.One.getZExtValue(), Res2.One.getZExtValue());
123   EXPECT_EQ(Res.Zero.getZExtValue(), Res2.Zero.getZExtValue());
124 }
125 
126 // Check that we know nothing when at least one value of a PHI
127 // comes from something we cannot analysis.
128 // This test is not particularly interesting, it is just
129 // here to cover the code that stops the analysis of PHIs
130 // earlier. In that case, we would not even look at the
131 // second incoming value.
132 TEST_F(AArch64GISelMITest, TestKnownBitsUnknownPHI) {
133   StringRef MIRString =
134       "  bb.10:\n"
135       "  %10:_(s64) = COPY %0\n"
136       "  %11:_(s1) = G_IMPLICIT_DEF\n"
137       "  G_BRCOND %11(s1), %bb.11\n"
138       "  G_BR %bb.12\n"
139       "\n"
140       "  bb.11:\n"
141       "  %12:_(s64) = G_CONSTANT i64 2\n"
142       "  G_BR %bb.12\n"
143       "\n"
144       "  bb.12:\n"
145       "  %13:_(s64) = PHI %10(s64), %bb.10, %12(s64), %bb.11\n"
146       "  %14:_(s64) = COPY %13\n";
147   setUp(MIRString);
148   if (!TM)
149     return;
150   Register CopyReg = Copies[Copies.size() - 1];
151   MachineInstr *FinalCopy = MRI->getVRegDef(CopyReg);
152   Register SrcReg = FinalCopy->getOperand(1).getReg();
153   Register DstReg = FinalCopy->getOperand(0).getReg();
154   GISelKnownBits Info(*MF);
155   KnownBits Res = Info.getKnownBits(SrcReg);
156   EXPECT_EQ((uint64_t)0, Res.One.getZExtValue());
157   EXPECT_EQ((uint64_t)0, Res.Zero.getZExtValue());
158 
159   KnownBits Res2 = Info.getKnownBits(DstReg);
160   EXPECT_EQ(Res.One.getZExtValue(), Res2.One.getZExtValue());
161   EXPECT_EQ(Res.Zero.getZExtValue(), Res2.Zero.getZExtValue());
162 }
163 
164 // Check that we manage to process PHIs that loop on themselves.
165 // For now, the analysis just stops and assumes it knows nothing,
166 // eventually we could teach it how to properly track phis that
167 // loop back.
168 TEST_F(AArch64GISelMITest, TestKnownBitsCstPHIWithLoop) {
169   StringRef MIRString =
170       "  bb.10:\n"
171       "  %10:_(s8) = G_CONSTANT i8 3\n"
172       "  %11:_(s1) = G_IMPLICIT_DEF\n"
173       "  G_BRCOND %11(s1), %bb.11\n"
174       "  G_BR %bb.12\n"
175       "\n"
176       "  bb.11:\n"
177       "  %12:_(s8) = G_CONSTANT i8 2\n"
178       "  G_BR %bb.12\n"
179       "\n"
180       "  bb.12:\n"
181       "  %13:_(s8) = PHI %10(s8), %bb.10, %12(s8), %bb.11, %14(s8), %bb.12\n"
182       "  %14:_(s8) = COPY %13\n"
183       "  G_BR %bb.12\n";
184   setUp(MIRString);
185   if (!TM)
186     return;
187   Register CopyReg = Copies[Copies.size() - 1];
188   MachineInstr *FinalCopy = MRI->getVRegDef(CopyReg);
189   Register SrcReg = FinalCopy->getOperand(1).getReg();
190   Register DstReg = FinalCopy->getOperand(0).getReg();
191   GISelKnownBits Info(*MF);
192   KnownBits Res = Info.getKnownBits(SrcReg);
193   EXPECT_EQ((uint64_t)0, Res.One.getZExtValue());
194   EXPECT_EQ((uint64_t)0, Res.Zero.getZExtValue());
195 
196   KnownBits Res2 = Info.getKnownBits(DstReg);
197   EXPECT_EQ(Res.One.getZExtValue(), Res2.One.getZExtValue());
198   EXPECT_EQ(Res.Zero.getZExtValue(), Res2.Zero.getZExtValue());
199 }
200 
201 // Check that we don't try to analysis PHIs progression.
202 // Setting a deep enough max depth would allow to effectively simulate
203 // what happens in the loop.
204 // Thus, with a deep enough depth, we could actually figure out
205 // that %14's zero known bits are actually at least what we know
206 // for %10, right shifted by one.
207 // However, this process is super expensive compile-time wise and
208 // we don't want to reach that conclusion while playing with max depth.
209 // For now, the analysis just stops and assumes it knows nothing
210 // on PHIs, but eventually we could teach it how to properly track
211 // phis that loop back without relying on the luck effect of max
212 // depth.
213 TEST_F(AArch64GISelMITest, TestKnownBitsDecreasingCstPHIWithLoop) {
214   StringRef MIRString = "  bb.10:\n"
215                         "  %10:_(s8) = G_CONSTANT i8 5\n"
216                         "  %11:_(s8) = G_CONSTANT i8 1\n"
217                         "\n"
218                         "  bb.12:\n"
219                         "  %13:_(s8) = PHI %10(s8), %bb.10, %14(s8), %bb.12\n"
220                         "  %14:_(s8) = G_LSHR %13, %11\n"
221                         "  %15:_(s8) = COPY %14\n"
222                         "  G_BR %bb.12\n";
223   setUp(MIRString);
224   if (!TM)
225     return;
226   Register CopyReg = Copies[Copies.size() - 1];
227   MachineInstr *FinalCopy = MRI->getVRegDef(CopyReg);
228   Register SrcReg = FinalCopy->getOperand(1).getReg();
229   Register DstReg = FinalCopy->getOperand(0).getReg();
230   GISelKnownBits Info(*MF, /*MaxDepth=*/24);
231   KnownBits Res = Info.getKnownBits(SrcReg);
232   EXPECT_EQ((uint64_t)0, Res.One.getZExtValue());
233   // A single iteration on the PHI (%13) gives:
234   // %10 has known zero of 0xFA
235   // %12 has known zero of 0x80 (we shift right by one so high bit is zero)
236   // Therefore, %14's known zero are 0x80 shifted by one 0xC0.
237   // If we had simulated the loop we could have more zero bits, basically
238   // up to 0xFC (count leading zero of 5, + 1).
239   EXPECT_EQ((uint64_t)0xC0, Res.Zero.getZExtValue());
240 
241   KnownBits Res2 = Info.getKnownBits(DstReg);
242   EXPECT_EQ(Res.One.getZExtValue(), Res2.One.getZExtValue());
243   EXPECT_EQ(Res.Zero.getZExtValue(), Res2.Zero.getZExtValue());
244 }
245 
246 TEST_F(AArch64GISelMITest, TestKnownBitsPtrToIntViceVersa) {
247   StringRef MIRString = "  %3:_(s16) = G_CONSTANT i16 256\n"
248                         "  %4:_(p0) = G_INTTOPTR %3\n"
249                         "  %5:_(s32) = G_PTRTOINT %4\n"
250                         "  %6:_(s32) = COPY %5\n";
251   setUp(MIRString);
252   if (!TM)
253     return;
254   unsigned CopyReg = Copies[Copies.size() - 1];
255   MachineInstr *FinalCopy = MRI->getVRegDef(CopyReg);
256   unsigned SrcReg = FinalCopy->getOperand(1).getReg();
257   GISelKnownBits Info(*MF);
258   KnownBits Res = Info.getKnownBits(SrcReg);
259   EXPECT_EQ(256u, Res.One.getZExtValue());
260   EXPECT_EQ(0xfffffeffu, Res.Zero.getZExtValue());
261 }
262 TEST_F(AArch64GISelMITest, TestKnownBitsXOR) {
263   StringRef MIRString = "  %3:_(s8) = G_CONSTANT i8 4\n"
264                         "  %4:_(s8) = G_CONSTANT i8 7\n"
265                         "  %5:_(s8) = G_XOR %3, %4\n"
266                         "  %6:_(s8) = COPY %5\n";
267   setUp(MIRString);
268   if (!TM)
269     return;
270   unsigned CopyReg = Copies[Copies.size() - 1];
271   MachineInstr *FinalCopy = MRI->getVRegDef(CopyReg);
272   unsigned SrcReg = FinalCopy->getOperand(1).getReg();
273   GISelKnownBits Info(*MF);
274   KnownBits Res = Info.getKnownBits(SrcReg);
275   EXPECT_EQ(3u, Res.One.getZExtValue());
276   EXPECT_EQ(252u, Res.Zero.getZExtValue());
277 }
278 
279 TEST_F(AArch64GISelMITest, TestKnownBits) {
280 
281   StringRef MIR = "  %3:_(s32) = G_TRUNC %0\n"
282                   "  %4:_(s32) = G_TRUNC %1\n"
283                   "  %5:_(s32) = G_CONSTANT i32 5\n"
284                   "  %6:_(s32) = G_CONSTANT i32 24\n"
285                   "  %7:_(s32) = G_CONSTANT i32 28\n"
286                   "  %14:_(p0) = G_INTTOPTR %7\n"
287                   "  %16:_(s32) = G_PTRTOINT %14\n"
288                   "  %8:_(s32) = G_SHL %3, %5\n"
289                   "  %9:_(s32) = G_SHL %4, %5\n"
290                   "  %10:_(s32) = G_OR %8, %6\n"
291                   "  %11:_(s32) = G_OR %9, %16\n"
292                   "  %12:_(s32) = G_MUL %10, %11\n"
293                   "  %13:_(s32) = COPY %12\n";
294   setUp(MIR);
295   if (!TM)
296     return;
297   unsigned CopyReg = Copies[Copies.size() - 1];
298   MachineInstr *FinalCopy = MRI->getVRegDef(CopyReg);
299   unsigned SrcReg = FinalCopy->getOperand(1).getReg();
300   GISelKnownBits Info(*MF);
301   KnownBits Known = Info.getKnownBits(SrcReg);
302   EXPECT_FALSE(Known.hasConflict());
303   EXPECT_EQ(32u, Known.One.getZExtValue());
304   EXPECT_EQ(95u, Known.Zero.getZExtValue());
305   APInt Zeroes = Info.getKnownZeroes(SrcReg);
306   EXPECT_EQ(Known.Zero, Zeroes);
307 }
308 
309 TEST_F(AArch64GISelMITest, TestSignBitIsZero) {
310   setUp();
311   if (!TM)
312     return;
313 
314   const LLT S32 = LLT::scalar(32);
315   auto SignBit = B.buildConstant(S32, 0x80000000);
316   auto Zero = B.buildConstant(S32, 0);
317 
318   GISelKnownBits KnownBits(*MF);
319 
320   EXPECT_TRUE(KnownBits.signBitIsZero(Zero.getReg(0)));
321   EXPECT_FALSE(KnownBits.signBitIsZero(SignBit.getReg(0)));
322 }
323 
324 TEST_F(AArch64GISelMITest, TestNumSignBitsConstant) {
325   StringRef MIRString = "  %3:_(s8) = G_CONSTANT i8 1\n"
326                         "  %4:_(s8) = COPY %3\n"
327 
328                         "  %5:_(s8) = G_CONSTANT i8 -1\n"
329                         "  %6:_(s8) = COPY %5\n"
330 
331                         "  %7:_(s8) = G_CONSTANT i8 127\n"
332                         "  %8:_(s8) = COPY %7\n"
333 
334                         "  %9:_(s8) = G_CONSTANT i8 32\n"
335                         "  %10:_(s8) = COPY %9\n"
336 
337                         "  %11:_(s8) = G_CONSTANT i8 -32\n"
338                         "  %12:_(s8) = COPY %11\n";
339   setUp(MIRString);
340   if (!TM)
341     return;
342   Register CopyReg1 = Copies[Copies.size() - 5];
343   Register CopyRegNeg1 = Copies[Copies.size() - 4];
344   Register CopyReg127 = Copies[Copies.size() - 3];
345   Register CopyReg32 = Copies[Copies.size() - 2];
346   Register CopyRegNeg32 = Copies[Copies.size() - 1];
347 
348   GISelKnownBits Info(*MF);
349   EXPECT_EQ(7u, Info.computeNumSignBits(CopyReg1));
350   EXPECT_EQ(8u, Info.computeNumSignBits(CopyRegNeg1));
351   EXPECT_EQ(1u, Info.computeNumSignBits(CopyReg127));
352   EXPECT_EQ(2u, Info.computeNumSignBits(CopyReg32));
353   EXPECT_EQ(3u, Info.computeNumSignBits(CopyRegNeg32));
354 }
355 
356 TEST_F(AArch64GISelMITest, TestNumSignBitsSext) {
357   StringRef MIRString = "  %3:_(p0) = G_IMPLICIT_DEF\n"
358                         "  %4:_(s8) = G_LOAD %3 :: (load 1)\n"
359                         "  %5:_(s32) = G_SEXT %4\n"
360                         "  %6:_(s32) = COPY %5\n"
361 
362                         "  %7:_(s8) = G_CONSTANT i8 -1\n"
363                         "  %8:_(s32) = G_SEXT %7\n"
364                         "  %9:_(s32) = COPY %8\n";
365   setUp(MIRString);
366   if (!TM)
367     return;
368   Register CopySextLoad = Copies[Copies.size() - 2];
369   Register CopySextNeg1 = Copies[Copies.size() - 1];
370 
371   GISelKnownBits Info(*MF);
372   EXPECT_EQ(25u, Info.computeNumSignBits(CopySextLoad));
373   EXPECT_EQ(32u, Info.computeNumSignBits(CopySextNeg1));
374 }
375 
376 TEST_F(AArch64GISelMITest, TestNumSignBitsSextInReg) {
377   StringRef MIRString = R"(
378    %ptr:_(p0) = G_IMPLICIT_DEF
379    %load4:_(s32) = G_LOAD %ptr :: (load 4)
380 
381    %inreg7:_(s32) = G_SEXT_INREG %load4, 7
382    %copy_inreg7:_(s32) = COPY %inreg7
383 
384    %inreg8:_(s32) = G_SEXT_INREG %load4, 8
385    %copy_inreg8:_(s32) = COPY %inreg8
386 
387    %inreg9:_(s32) = G_SEXT_INREG %load4, 9
388    %copy_inreg9:_(s32) = COPY %inreg9
389 
390    %inreg31:_(s32) = G_SEXT_INREG %load4, 31
391    %copy_inreg31:_(s32) = COPY %inreg31
392 
393    %load1:_(s8) = G_LOAD %ptr :: (load 1)
394    %sext_load1:_(s32) = G_SEXT %load1
395 
396    %inreg6_sext:_(s32) = G_SEXT_INREG %sext_load1, 6
397    %copy_inreg6_sext:_(s32) = COPY %inreg6_sext
398 
399    %inreg7_sext:_(s32) = G_SEXT_INREG %sext_load1, 7
400    %copy_inreg7_sext:_(s32) = COPY %inreg7_sext
401 
402    %inreg8_sext:_(s32) = G_SEXT_INREG %sext_load1, 8
403    %copy_inreg8_sext:_(s32) = COPY %inreg8_sext
404 
405    %inreg9_sext:_(s32) = G_SEXT_INREG %sext_load1, 9
406    %copy_inreg9_sext:_(s32) = COPY %inreg9_sext
407 
408    %inreg31_sext:_(s32) = G_SEXT_INREG %sext_load1, 31
409    %copy_inreg31_sext:_(s32) = COPY %inreg31_sext
410 )";
411 
412   setUp(MIRString);
413   if (!TM)
414     return;
415 
416   Register CopyInReg7 = Copies[Copies.size() - 9];
417   Register CopyInReg8 = Copies[Copies.size() - 8];
418   Register CopyInReg9 = Copies[Copies.size() - 7];
419   Register CopyInReg31 = Copies[Copies.size() - 6];
420 
421   Register CopyInReg6Sext = Copies[Copies.size() - 5];
422   Register CopyInReg7Sext = Copies[Copies.size() - 4];
423   Register CopyInReg8Sext = Copies[Copies.size() - 3];
424   Register CopyInReg9Sext = Copies[Copies.size() - 2];
425   Register CopyInReg31Sext = Copies[Copies.size() - 1];
426 
427   GISelKnownBits Info(*MF);
428   EXPECT_EQ(26u, Info.computeNumSignBits(CopyInReg7));
429   EXPECT_EQ(25u, Info.computeNumSignBits(CopyInReg8));
430   EXPECT_EQ(24u, Info.computeNumSignBits(CopyInReg9));
431   EXPECT_EQ(2u, Info.computeNumSignBits(CopyInReg31));
432 
433   EXPECT_EQ(27u, Info.computeNumSignBits(CopyInReg6Sext));
434   EXPECT_EQ(26u, Info.computeNumSignBits(CopyInReg7Sext));
435   EXPECT_EQ(25u, Info.computeNumSignBits(CopyInReg8Sext));
436   EXPECT_EQ(25u, Info.computeNumSignBits(CopyInReg9Sext));
437   EXPECT_EQ(25u, Info.computeNumSignBits(CopyInReg31Sext));
438 }
439 
440 TEST_F(AArch64GISelMITest, TestNumSignBitsTrunc) {
441   StringRef MIRString = "  %3:_(p0) = G_IMPLICIT_DEF\n"
442                         "  %4:_(s32) = G_LOAD %3 :: (load 4)\n"
443                         "  %5:_(s8) = G_TRUNC %4\n"
444                         "  %6:_(s8) = COPY %5\n"
445 
446                         "  %7:_(s32) = G_CONSTANT i32 -1\n"
447                         "  %8:_(s8) = G_TRUNC %7\n"
448                         "  %9:_(s8) = COPY %8\n"
449 
450                         "  %10:_(s32) = G_CONSTANT i32 7\n"
451                         "  %11:_(s8) = G_TRUNC %10\n"
452                         "  %12:_(s8) = COPY %11\n";
453   setUp(MIRString);
454   if (!TM)
455     return;
456   Register CopyTruncLoad = Copies[Copies.size() - 3];
457   Register CopyTruncNeg1 = Copies[Copies.size() - 2];
458   Register CopyTrunc7 = Copies[Copies.size() - 1];
459 
460   GISelKnownBits Info(*MF);
461   EXPECT_EQ(1u, Info.computeNumSignBits(CopyTruncLoad));
462   EXPECT_EQ(8u, Info.computeNumSignBits(CopyTruncNeg1));
463   EXPECT_EQ(5u, Info.computeNumSignBits(CopyTrunc7));
464 }
465 
466 TEST_F(AMDGPUGISelMITest, TestNumSignBitsTrunc) {
467   StringRef MIRString =
468     "  %3:_(<4 x s32>) = G_IMPLICIT_DEF\n"
469     "  %4:_(s32) = G_IMPLICIT_DEF\n"
470     "  %5:_(s32) = G_AMDGPU_BUFFER_LOAD_UBYTE %3, %4, %4, %4, 0, 0, 0 :: (load 1)\n"
471     "  %6:_(s32) = COPY %5\n"
472 
473     "  %7:_(s32) = G_AMDGPU_BUFFER_LOAD_SBYTE %3, %4, %4, %4, 0, 0, 0 :: (load 1)\n"
474     "  %8:_(s32) = COPY %7\n"
475 
476     "  %9:_(s32) = G_AMDGPU_BUFFER_LOAD_USHORT %3, %4, %4, %4, 0, 0, 0 :: (load 2)\n"
477     "  %10:_(s32) = COPY %9\n"
478 
479     "  %11:_(s32) = G_AMDGPU_BUFFER_LOAD_SSHORT %3, %4, %4, %4, 0, 0, 0 :: (load 2)\n"
480     "  %12:_(s32) = COPY %11\n";
481 
482   setUp(MIRString);
483   if (!TM)
484     return;
485 
486   Register CopyLoadUByte = Copies[Copies.size() - 4];
487   Register CopyLoadSByte = Copies[Copies.size() - 3];
488   Register CopyLoadUShort = Copies[Copies.size() - 2];
489   Register CopyLoadSShort = Copies[Copies.size() - 1];
490 
491   GISelKnownBits Info(*MF);
492 
493   EXPECT_EQ(24u, Info.computeNumSignBits(CopyLoadUByte));
494   EXPECT_EQ(25u, Info.computeNumSignBits(CopyLoadSByte));
495   EXPECT_EQ(16u, Info.computeNumSignBits(CopyLoadUShort));
496   EXPECT_EQ(17u, Info.computeNumSignBits(CopyLoadSShort));
497 }
498 
499 TEST_F(AMDGPUGISelMITest, TestTargetKnownAlign) {
500   StringRef MIRString =
501     "  %5:_(p4) = G_INTRINSIC intrinsic(@llvm.amdgcn.dispatch.ptr)\n"
502     "  %6:_(p4) = COPY %5\n"
503     "  %7:_(p4) = G_INTRINSIC intrinsic(@llvm.amdgcn.queue.ptr)\n"
504     "  %8:_(p4) = COPY %7\n"
505     "  %9:_(p4) = G_INTRINSIC intrinsic(@llvm.amdgcn.kernarg.segment.ptr)\n"
506     "  %10:_(p4) = COPY %9\n"
507     "  %11:_(p4) = G_INTRINSIC intrinsic(@llvm.amdgcn.implicitarg.ptr)\n"
508     "  %12:_(p4) = COPY %11\n"
509     "  %13:_(p4) = G_INTRINSIC intrinsic(@llvm.amdgcn.implicit.buffer.ptr)\n"
510     "  %14:_(p4) = COPY %13\n";
511 
512   setUp(MIRString);
513   if (!TM)
514     return;
515 
516   Register CopyDispatchPtr = Copies[Copies.size() - 5];
517   Register CopyQueuePtr = Copies[Copies.size() - 4];
518   Register CopyKernargSegmentPtr = Copies[Copies.size() - 3];
519   Register CopyImplicitArgPtr = Copies[Copies.size() - 2];
520   Register CopyImplicitBufferPtr = Copies[Copies.size() - 1];
521 
522   GISelKnownBits Info(*MF);
523 
524   EXPECT_EQ(Align(4), Info.computeKnownAlignment(CopyDispatchPtr));
525   EXPECT_EQ(Align(4), Info.computeKnownAlignment(CopyQueuePtr));
526   EXPECT_EQ(Align(4), Info.computeKnownAlignment(CopyKernargSegmentPtr));
527   EXPECT_EQ(Align(4), Info.computeKnownAlignment(CopyImplicitArgPtr));
528   EXPECT_EQ(Align(4), Info.computeKnownAlignment(CopyImplicitBufferPtr));
529 }
530 
531 TEST_F(AMDGPUGISelMITest, TestIsKnownToBeAPowerOfTwo) {
532 
533   StringRef MIRString = R"MIR(
534   %zero:_(s32) = G_CONSTANT i32 0
535   %one:_(s32) = G_CONSTANT i32 1
536   %two:_(s32) = G_CONSTANT i32 2
537   %three:_(s32) = G_CONSTANT i32 3
538   %five:_(s32) = G_CONSTANT i32 5
539   %copy_zero:_(s32) = COPY %zero
540   %copy_one:_(s32) = COPY %one
541   %copy_two:_(s32) = COPY %two
542   %copy_three:_(s32) = COPY %three
543 
544   %trunc_two:_(s1) = G_TRUNC %two
545   %trunc_three:_(s1) = G_TRUNC %three
546   %trunc_five:_(s1) = G_TRUNC %five
547 
548   %copy_trunc_two:_(s1) = COPY %trunc_two
549   %copy_trunc_three:_(s1) = COPY %trunc_three
550   %copy_trunc_five:_(s1) = COPY %trunc_five
551 
552   %ptr:_(p1) = G_IMPLICIT_DEF
553   %shift_amt:_(s32) = G_LOAD %ptr :: (load 4, addrspace 1)
554 
555   %shl_1:_(s32) = G_SHL %one, %shift_amt
556   %copy_shl_1:_(s32) = COPY %shl_1
557 
558   %shl_2:_(s32) = G_SHL %two, %shift_amt
559   %copy_shl_2:_(s32) = COPY %shl_2
560 
561   %not_sign_mask:_(s32) = G_LOAD %ptr :: (load 4, addrspace 1)
562   %sign_mask:_(s32) = G_CONSTANT i32 -2147483648
563 
564   %lshr_not_sign_mask:_(s32) = G_LSHR %not_sign_mask, %shift_amt
565   %copy_lshr_not_sign_mask:_(s32) = COPY %lshr_not_sign_mask
566 
567   %lshr_sign_mask:_(s32) = G_LSHR %sign_mask, %shift_amt
568   %copy_lshr_sign_mask:_(s32) = COPY %lshr_sign_mask
569 
570   %or_pow2:_(s32) = G_OR %zero, %two
571   %copy_or_pow2:_(s32) = COPY %or_pow2
572 
573 )MIR";
574   setUp(MIRString);
575   if (!TM)
576     return;
577 
578   GISelKnownBits KB(*MF);
579 
580   Register CopyZero = Copies[Copies.size() - 12];
581   Register CopyOne = Copies[Copies.size() - 11];
582   Register CopyTwo = Copies[Copies.size() - 10];
583   Register CopyThree = Copies[Copies.size() - 9];
584   Register CopyTruncTwo = Copies[Copies.size() - 8];
585   Register CopyTruncThree = Copies[Copies.size() - 7];
586   Register CopyTruncFive = Copies[Copies.size() - 6];
587 
588   Register CopyShl1 = Copies[Copies.size() - 5];
589   Register CopyShl2 = Copies[Copies.size() - 4];
590 
591   Register CopyLShrNotSignMask = Copies[Copies.size() - 3];
592   Register CopyLShrSignMask = Copies[Copies.size() - 2];
593   Register CopyOrPow2 = Copies[Copies.size() - 1];
594 
595   EXPECT_FALSE(isKnownToBeAPowerOfTwo(CopyZero, *MRI, &KB));
596   EXPECT_TRUE(isKnownToBeAPowerOfTwo(CopyOne, *MRI, &KB));
597   EXPECT_TRUE(isKnownToBeAPowerOfTwo(CopyTwo, *MRI, &KB));
598   EXPECT_FALSE(isKnownToBeAPowerOfTwo(CopyThree, *MRI, &KB));
599 
600   EXPECT_FALSE(isKnownToBeAPowerOfTwo(CopyTruncTwo, *MRI, &KB));
601   EXPECT_TRUE(isKnownToBeAPowerOfTwo(CopyTruncThree, *MRI, &KB));
602   EXPECT_TRUE(isKnownToBeAPowerOfTwo(CopyTruncFive, *MRI, &KB));
603 
604   EXPECT_TRUE(isKnownToBeAPowerOfTwo(CopyShl1, *MRI, &KB));
605   EXPECT_FALSE(isKnownToBeAPowerOfTwo(CopyShl2, *MRI, &KB));
606 
607   EXPECT_FALSE(isKnownToBeAPowerOfTwo(CopyLShrNotSignMask, *MRI, &KB));
608   EXPECT_TRUE(isKnownToBeAPowerOfTwo(CopyLShrSignMask, *MRI, &KB));
609   EXPECT_TRUE(isKnownToBeAPowerOfTwo(CopyOrPow2, *MRI, &KB));
610 }
611 
612 TEST_F(AArch64GISelMITest, TestMetadata) {
613   StringRef MIRString = "  %imp:_(p0) = G_IMPLICIT_DEF\n"
614                         "  %load:_(s8) = G_LOAD %imp(p0) :: (load 1)\n"
615                         "  %ext:_(s32) = G_ZEXT %load(s8)\n"
616                         "  %cst:_(s32) = G_CONSTANT i32 1\n"
617                         "  %and:_(s32) = G_AND %ext, %cst\n"
618                         "  %copy:_(s32) = COPY %and(s32)\n";
619   setUp(MIRString);
620   if (!TM)
621     return;
622 
623   Register CopyReg = Copies[Copies.size() - 1];
624   MachineInstr *FinalCopy = MRI->getVRegDef(CopyReg);
625   Register SrcReg = FinalCopy->getOperand(1).getReg();
626 
627   // We need a load with a metadata range for this to break. Fudge the load in
628   // the string and replace it with something we can work with.
629   MachineInstr *And = MRI->getVRegDef(SrcReg);
630   MachineInstr *Ext = MRI->getVRegDef(And->getOperand(1).getReg());
631   MachineInstr *Load = MRI->getVRegDef(Ext->getOperand(1).getReg());
632   IntegerType *Int8Ty = Type::getInt8Ty(Context);
633 
634   // Value must be in [0, 2)
635   Metadata *LowAndHigh[] = {
636       ConstantAsMetadata::get(ConstantInt::get(Int8Ty, 0)),
637       ConstantAsMetadata::get(ConstantInt::get(Int8Ty, 2))};
638   auto NewMDNode = MDNode::get(Context, LowAndHigh);
639   const MachineMemOperand *OldMMO = *Load->memoperands_begin();
640   MachineMemOperand NewMMO(OldMMO->getPointerInfo(), OldMMO->getFlags(),
641                            OldMMO->getSizeInBits(), OldMMO->getAlign(),
642                            OldMMO->getAAInfo(), NewMDNode);
643   MachineIRBuilder MIB(*Load);
644   MIB.buildLoad(Load->getOperand(0), Load->getOperand(1), NewMMO);
645   Load->eraseFromParent();
646 
647   GISelKnownBits Info(*MF);
648   KnownBits Res = Info.getKnownBits(And->getOperand(1).getReg());
649 
650   // We don't know what the result of the load is, so we don't know any ones.
651   EXPECT_TRUE(Res.One.isNullValue());
652 
653   // We know that the value is in [0, 2). So, we don't know if the first bit
654   // is 0 or not. However, we do know that every other bit must be 0.
655   APInt Mask(Res.getBitWidth(), 1);
656   Mask.flipAllBits();
657   EXPECT_EQ(Mask.getZExtValue(), Res.Zero.getZExtValue());
658 }
659 
660 TEST_F(AArch64GISelMITest, TestKnownBitsExt) {
661   StringRef MIRString = "  %c1:_(s16) = G_CONSTANT i16 1\n"
662                         "  %x:_(s16) = G_IMPLICIT_DEF\n"
663                         "  %y:_(s16) = G_AND %x, %c1\n"
664                         "  %anyext:_(s32) = G_ANYEXT %y(s16)\n"
665                         "  %r1:_(s32) = COPY %anyext\n"
666                         "  %zext:_(s32) = G_ZEXT %y(s16)\n"
667                         "  %r2:_(s32) = COPY %zext\n"
668                         "  %sext:_(s32) = G_SEXT %y(s16)\n"
669                         "  %r3:_(s32) = COPY %sext\n";
670   setUp(MIRString);
671   if (!TM)
672     return;
673   Register CopyRegAny = Copies[Copies.size() - 3];
674   Register CopyRegZ = Copies[Copies.size() - 2];
675   Register CopyRegS = Copies[Copies.size() - 1];
676 
677   GISelKnownBits Info(*MF);
678   MachineInstr *Copy;
679   Register SrcReg;
680   KnownBits Res;
681 
682   Copy = MRI->getVRegDef(CopyRegAny);
683   SrcReg = Copy->getOperand(1).getReg();
684   Res = Info.getKnownBits(SrcReg);
685   EXPECT_EQ((uint64_t)32, Res.getBitWidth());
686   EXPECT_EQ((uint64_t)0, Res.One.getZExtValue());
687   EXPECT_EQ((uint64_t)0x0000fffe, Res.Zero.getZExtValue());
688 
689   Copy = MRI->getVRegDef(CopyRegZ);
690   SrcReg = Copy->getOperand(1).getReg();
691   Res = Info.getKnownBits(SrcReg);
692   EXPECT_EQ((uint64_t)32, Res.getBitWidth());
693   EXPECT_EQ((uint64_t)0, Res.One.getZExtValue());
694   EXPECT_EQ((uint64_t)0xfffffffe, Res.Zero.getZExtValue());
695 
696   Copy = MRI->getVRegDef(CopyRegS);
697   SrcReg = Copy->getOperand(1).getReg();
698   Res = Info.getKnownBits(SrcReg);
699   EXPECT_EQ((uint64_t)32, Res.getBitWidth());
700   EXPECT_EQ((uint64_t)0, Res.One.getZExtValue());
701   EXPECT_EQ((uint64_t)0xfffffffe, Res.Zero.getZExtValue());
702 }
703 
704 TEST_F(AArch64GISelMITest, TestKnownBitsSextInReg) {
705   StringRef MIRString = R"(
706    ; 000...0001
707    %one:_(s32) = G_CONSTANT i32 1
708 
709    ; 000...0010
710    %two:_(s32) = G_CONSTANT i32 2
711 
712    ; 000...1010
713    %ten:_(s32) = G_CONSTANT i32 10
714 
715    ; ???...????
716    %w0:_(s32) = COPY $w0
717 
718    ; ???...?1?
719    %or:_(s32) = G_OR %w0, %two
720 
721    ; All bits are known.
722    %inreg1:_(s32) = G_SEXT_INREG %one, 1
723    %copy_inreg1:_(s32) = COPY %inreg1
724 
725    ; All bits unknown
726    %inreg2:_(s32) = G_SEXT_INREG %or, 1
727    %copy_inreg2:_(s32) = COPY %inreg2
728 
729    ; Extending from the only (known) set bit
730    ; 111...11?
731    %inreg3:_(s32) = G_SEXT_INREG %or, 2
732    %copy_inreg3:_(s32) = COPY %inreg3
733 
734    ; Extending from a known set bit, overwriting all of the high set bits.
735    ; 111...1110
736    %inreg4:_(s32) = G_SEXT_INREG %ten, 2
737    %copy_inreg4:_(s32) = COPY %inreg4
738 
739 )";
740   setUp(MIRString);
741   if (!TM)
742     return;
743   GISelKnownBits Info(*MF);
744   KnownBits Res;
745   auto GetKB = [&](unsigned Idx) {
746     Register CopyReg = Copies[Idx];
747     auto *Copy = MRI->getVRegDef(CopyReg);
748     return Info.getKnownBits(Copy->getOperand(1).getReg());
749   };
750 
751   // Every bit is known to be a 1.
752   Res = GetKB(Copies.size() - 4);
753   EXPECT_EQ(32u, Res.getBitWidth());
754   EXPECT_TRUE(Res.isAllOnes());
755 
756   // All bits are unknown
757   Res = GetKB(Copies.size() - 3);
758   EXPECT_EQ(32u, Res.getBitWidth());
759   EXPECT_TRUE(Res.isUnknown());
760 
761   // Extending from the only known set bit
762   // 111...11?
763   Res = GetKB(Copies.size() - 2);
764   EXPECT_EQ(32u, Res.getBitWidth());
765   EXPECT_EQ(0xFFFFFFFEu, Res.One.getZExtValue());
766   EXPECT_EQ(0u, Res.Zero.getZExtValue());
767 
768   // Extending from a known set bit, overwriting all of the high set bits.
769   // 111...1110
770   Res = GetKB(Copies.size() - 1);
771   EXPECT_EQ(32u, Res.getBitWidth());
772   EXPECT_EQ(0xFFFFFFFEu, Res.One.getZExtValue());
773   EXPECT_EQ(1u, Res.Zero.getZExtValue());
774 }
775 
776 TEST_F(AArch64GISelMITest, TestKnownBitsMergeValues) {
777   StringRef MIRString = R"(
778    %val0:_(s16) = G_CONSTANT i16 35224
779    %val1:_(s16) = G_CONSTANT i16 17494
780    %val2:_(s16) = G_CONSTANT i16 4659
781    %val3:_(s16) = G_CONSTANT i16 43981
782    %merge:_(s64) = G_MERGE_VALUES %val0, %val1, %val2, %val3
783    %mergecopy:_(s64) = COPY %merge
784 )";
785   setUp(MIRString);
786   if (!TM)
787     return;
788 
789   const uint64_t TestVal = UINT64_C(0xabcd123344568998);
790   Register CopyMerge = Copies[Copies.size() - 1];
791 
792   GISelKnownBits Info(*MF);
793   KnownBits Res = Info.getKnownBits(CopyMerge);
794   EXPECT_EQ(64u, Res.getBitWidth());
795   EXPECT_EQ(TestVal, Res.One.getZExtValue());
796   EXPECT_EQ(~TestVal, Res.Zero.getZExtValue());
797 }
798 
799 TEST_F(AArch64GISelMITest, TestKnownBitsUnmergeValues) {
800   StringRef MIRString = R"(
801    %val:_(s64) = G_CONSTANT i64 12379570962110515608
802    %val0:_(s16), %val1:_(s16), %val2:_(s16), %val3:_(s16) = G_UNMERGE_VALUES %val
803    %part0:_(s16) = COPY %val0
804    %part1:_(s16) = COPY %val1
805    %part2:_(s16) = COPY %val2
806    %part3:_(s16) = COPY %val3
807 
808 )";
809   setUp(MIRString);
810   if (!TM)
811     return;
812 
813   const uint64_t TestVal = UINT64_C(0xabcd123344568998);
814   GISelKnownBits Info(*MF);
815 
816   int Offset = -4;
817   for (unsigned BitOffset = 0; BitOffset != 64; BitOffset += 16, ++Offset) {
818     Register Part = Copies[Copies.size() + Offset];
819     KnownBits PartKnown = Info.getKnownBits(Part);
820     EXPECT_EQ(16u, PartKnown.getBitWidth());
821 
822     uint16_t PartTestVal = static_cast<uint16_t>(TestVal >> BitOffset);
823     EXPECT_EQ(PartTestVal, PartKnown.One.getZExtValue());
824     EXPECT_EQ(static_cast<uint16_t>(~PartTestVal), PartKnown.Zero.getZExtValue());
825   }
826 }
827 
828 TEST_F(AArch64GISelMITest, TestKnownBitsBSwapBitReverse) {
829   StringRef MIRString = R"(
830    %const:_(s32) = G_CONSTANT i32 287454020
831    %bswap:_(s32) = G_BSWAP %const
832    %bitreverse:_(s32) = G_BITREVERSE %const
833    %copy_bswap:_(s32) = COPY %bswap
834    %copy_bitreverse:_(s32) = COPY %bitreverse
835 )";
836   setUp(MIRString);
837   if (!TM)
838     return;
839 
840   const uint32_t TestVal = 0x11223344;
841 
842   Register CopyBSwap = Copies[Copies.size() - 2];
843   Register CopyBitReverse = Copies[Copies.size() - 1];
844 
845   GISelKnownBits Info(*MF);
846 
847   KnownBits BSwapKnown = Info.getKnownBits(CopyBSwap);
848   EXPECT_EQ(32u, BSwapKnown.getBitWidth());
849   EXPECT_EQ(TestVal, BSwapKnown.One.getZExtValue());
850   EXPECT_EQ(~TestVal, BSwapKnown.Zero.getZExtValue());
851 
852   KnownBits BitReverseKnown = Info.getKnownBits(CopyBitReverse);
853   EXPECT_EQ(32u, BitReverseKnown.getBitWidth());
854   EXPECT_EQ(TestVal, BitReverseKnown.One.getZExtValue());
855   EXPECT_EQ(~TestVal, BitReverseKnown.Zero.getZExtValue());
856 }
857 
858 TEST_F(AArch64GISelMITest, TestKnownBitsUMax) {
859   StringRef MIRString = R"(
860    %val:_(s32) = COPY $w0
861    %zext:_(s64) = G_ZEXT %val
862    %const:_(s64) = G_CONSTANT i64 -256
863    %umax:_(s64) = G_UMAX %zext, %const
864    %copy_umax:_(s64) = COPY %umax
865 )";
866   setUp(MIRString);
867   if (!TM)
868     return;
869 
870   Register CopyUMax = Copies[Copies.size() - 1];
871   GISelKnownBits Info(*MF);
872 
873   KnownBits KnownUmax = Info.getKnownBits(CopyUMax);
874   EXPECT_EQ(64u, KnownUmax.getBitWidth());
875   EXPECT_EQ(0xffu, KnownUmax.Zero.getZExtValue());
876   EXPECT_EQ(0xffffffffffffff00, KnownUmax.One.getZExtValue());
877 
878   EXPECT_EQ(0xffu, KnownUmax.Zero.getZExtValue());
879   EXPECT_EQ(0xffffffffffffff00, KnownUmax.One.getZExtValue());
880 }
881 
882 TEST_F(AArch64GISelMITest, TestInvalidQueries) {
883   StringRef MIRString = R"(
884    %src:_(s32) = COPY $w0
885    %thirty2:_(s32) = G_CONSTANT i32 32
886    %equalSized:_(s32) = G_SHL %src, %thirty2
887    %copy1:_(s32) = COPY %equalSized
888    %thirty3:_(s32) = G_CONSTANT i32 33
889    %biggerSized:_(s32) = G_SHL %src, %thirty3
890    %copy2:_(s32) = COPY %biggerSized
891 )";
892   setUp(MIRString);
893   if (!TM)
894     return;
895 
896   Register EqSizedCopyReg = Copies[Copies.size() - 2];
897   MachineInstr *EqSizedCopy = MRI->getVRegDef(EqSizedCopyReg);
898   Register EqSizedShl = EqSizedCopy->getOperand(1).getReg();
899 
900   Register BiggerSizedCopyReg = Copies[Copies.size() - 1];
901   MachineInstr *BiggerSizedCopy = MRI->getVRegDef(BiggerSizedCopyReg);
902   Register BiggerSizedShl = BiggerSizedCopy->getOperand(1).getReg();
903 
904   GISelKnownBits Info(*MF);
905   KnownBits EqSizeRes = Info.getKnownBits(EqSizedShl);
906   KnownBits BiggerSizeRes = Info.getKnownBits(BiggerSizedShl);
907 
908 
909   // We don't know what the result of the shift is, but we should not crash
910   EXPECT_TRUE(EqSizeRes.One.isNullValue());
911   EXPECT_TRUE(EqSizeRes.Zero.isNullValue());
912 
913   EXPECT_TRUE(BiggerSizeRes.One.isNullValue());
914   EXPECT_TRUE(BiggerSizeRes.Zero.isNullValue());
915 }
916 
917 TEST_F(AArch64GISelMITest, TestKnownBitsAssertZext) {
918   StringRef MIRString = R"(
919    %copy:_(s64) = COPY $x0
920 
921    %assert8:_(s64) = G_ASSERT_ZEXT %copy, 8
922    %copy_assert8:_(s64) = COPY %assert8
923 
924    %assert1:_(s64) = G_ASSERT_ZEXT %copy, 1
925    %copy_assert1:_(s64) = COPY %assert1
926 
927    %assert63:_(s64) = G_ASSERT_ZEXT %copy, 63
928    %copy_assert63:_(s64) = COPY %assert63
929 
930    %assert3:_(s64) = G_ASSERT_ZEXT %copy, 3
931    %copy_assert3:_(s64) = COPY %assert3
932 )";
933 
934   setUp(MIRString);
935   if (!TM)
936     return;
937 
938   Register CopyAssert8 = Copies[Copies.size() - 4];
939   Register CopyAssert1 = Copies[Copies.size() - 3];
940   Register CopyAssert63 = Copies[Copies.size() - 2];
941   Register CopyAssert3 = Copies[Copies.size() - 1];
942 
943   GISelKnownBits Info(*MF);
944   MachineInstr *Copy;
945   Register SrcReg;
946   KnownBits Res;
947 
948   // Assert zero-extension from an 8-bit value.
949   Copy = MRI->getVRegDef(CopyAssert8);
950   SrcReg = Copy->getOperand(1).getReg();
951   Res = Info.getKnownBits(SrcReg);
952   EXPECT_EQ(64u, Res.getBitWidth());
953   EXPECT_EQ(0u, Res.One.getZExtValue());
954   EXPECT_EQ(0xFFFFFFFFFFFFFF00u, Res.Zero.getZExtValue());
955 
956   // Assert zero-extension from a 1-bit value.
957   Copy = MRI->getVRegDef(CopyAssert1);
958   SrcReg = Copy->getOperand(1).getReg();
959   Res = Info.getKnownBits(SrcReg);
960   EXPECT_EQ(64u, Res.getBitWidth());
961   EXPECT_EQ(0u, Res.One.getZExtValue());
962   EXPECT_EQ(0xFFFFFFFFFFFFFFFE, Res.Zero.getZExtValue());
963 
964   // Assert zero-extension from a 63-bit value.
965   Copy = MRI->getVRegDef(CopyAssert63);
966   SrcReg = Copy->getOperand(1).getReg();
967   Res = Info.getKnownBits(SrcReg);
968   EXPECT_EQ(64u, Res.getBitWidth());
969   EXPECT_EQ(0u, Res.One.getZExtValue());
970   EXPECT_EQ(0x8000000000000000u, Res.Zero.getZExtValue());
971 
972   // Assert zero-extension from a 3-bit value.
973   Copy = MRI->getVRegDef(CopyAssert3);
974   SrcReg = Copy->getOperand(1).getReg();
975   Res = Info.getKnownBits(SrcReg);
976   EXPECT_EQ(64u, Res.getBitWidth());
977   EXPECT_EQ(0u, Res.One.getZExtValue());
978   EXPECT_EQ(0xFFFFFFFFFFFFFFF8u, Res.Zero.getZExtValue());
979 }
980