[llvm] [SCEV] Add predicate in SolveLinEq to ensure B is a multiple of A. (PR #108777)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `reverse-iteration` running on `hexagon-build-03` while building `llvm` at step 6 "check_all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/110/builds/1494

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 6 (check_all) failure: test (failure)
******************** TEST 'LLVM :: Analysis/ScalarEvolution/ne-overflow.ll' FAILED ********************
Exit Code: 1

Command Output (stderr):
--
RUN: at line 2: /local/mnt/workspace/bots/hexagon-build-03/reverse-iteration/llvm.obj/bin/opt /local/mnt/workspace/bots/hexagon-build-03/reverse-iteration/llvm.src/llvm/test/Analysis/ScalarEvolution/ne-overflow.ll -passes='print<scalar-evolution>' -scalar-evolution-classify-expressions=0 -disable-output 2>&1 | /local/mnt/workspace/bots/hexagon-build-03/reverse-iteration/llvm.obj/bin/FileCheck /local/mnt/workspace/bots/hexagon-build-03/reverse-iteration/llvm.src/llvm/test/Analysis/ScalarEvolution/ne-overflow.ll
+ /local/mnt/workspace/bots/hexagon-build-03/reverse-iteration/llvm.obj/bin/opt /local/mnt/workspace/bots/hexagon-build-03/reverse-iteration/llvm.src/llvm/test/Analysis/ScalarEvolution/ne-overflow.ll '-passes=print<scalar-evolution>' -scalar-evolution-classify-expressions=0 -disable-output
+ /local/mnt/workspace/bots/hexagon-build-03/reverse-iteration/llvm.obj/bin/FileCheck /local/mnt/workspace/bots/hexagon-build-03/reverse-iteration/llvm.src/llvm/test/Analysis/ScalarEvolution/ne-overflow.ll
/local/mnt/workspace/bots/hexagon-build-03/reverse-iteration/llvm.src/llvm/test/Analysis/ScalarEvolution/ne-overflow.ll:355:15: error: CHECK-NEXT: is not on the line after the previous match
; CHECK-NEXT: {0,+,2}<%for.body> Added Flags: <nssw>
              ^
<stdin>:148:2: note: 'next' match was here
 {0,+,2}<%for.body> Added Flags: <nssw>
 ^
<stdin>:146:13: note: previous match ended here
 Predicates:
            ^
<stdin>:147:1: note: non-matching line after previous match is here
 {0,+,2}<%for.body> Added Flags: <nusw>
^

Input file: <stdin>
Check file: /local/mnt/workspace/bots/hexagon-build-03/reverse-iteration/llvm.src/llvm/test/Analysis/ScalarEvolution/ne-overflow.ll

-dump-input=help explains the following input dump.

Input was:
<<<<<<
          .
          .
          .
        143: Loop %for.body: Unpredictable constant max backedge-taken count.  
        144: Loop %for.body: Unpredictable symbolic max backedge-taken count.  
        145: Loop %for.body: Predicated backedge-taken count is (%N /u 2) 
        146:  Predicates: 
        147:  {0,+,2}<%for.body> Added Flags: <nusw> 
        148:  {0,+,2}<%for.body> Added Flags: <nssw> 
next:355      !~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  error: match on wrong line
        149:  Equal predicate: (zext i1 (trunc i64 %N to i1) to i64) == 0 
        150: Loop %for.body: Predicated constant max backedge-taken count is i64 9223372036854775807 
        151:  Predicates: 
        152:  {0,+,2}<%for.body> Added Flags: <nusw> 
        153:  {0,+,2}<%for.body> Added Flags: <nssw> 
          .
          .
          .
>>>>>>

--

...

```

</details>

https://github.com/llvm/llvm-project/pull/108777