[llvm] [GISel] Teach computeKnownBitsImpl to handle COPY instructions that change bit width. (PR #118924)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-clang-x86_64-darwin` running on `doug-worker-3` while building `llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/23/builds/5587

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

```
Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'Clang :: Index/reparsed-live-issue.cpp' FAILED ********************
Exit Code: 1

Command Output (stderr):
--
RUN: at line 1: env CINDEXTEST_EDITING=1 LIBCLANG_DISABLE_CRASH_RECOVERY=1 /Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/c-index-test -test-load-source-reparse 2 none -remap-file-0=/Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Index/Inputs/reparse-issue.h,/Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Index/Inputs/reparse-issue.h-0 -remap-file-1=/Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Index/Inputs/reparse-issue.h,/Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Index/Inputs/reparse-issue.h-1 -- /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Index/reparsed-live-issue.cpp 2>&1 | /Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/FileCheck /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Index/reparsed-live-issue.cpp
+ env CINDEXTEST_EDITING=1 LIBCLANG_DISABLE_CRASH_RECOVERY=1 /Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/c-index-test -test-load-source-reparse 2 none -remap-file-0=/Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Index/Inputs/reparse-issue.h,/Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Index/Inputs/reparse-issue.h-0 -remap-file-1=/Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Index/Inputs/reparse-issue.h,/Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Index/Inputs/reparse-issue.h-1 -- /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Index/reparsed-live-issue.cpp
+ /Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/FileCheck /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Index/reparsed-live-issue.cpp
/Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Index/reparsed-live-issue.cpp:4:11: error: CHECK: expected string not found in input
// CHECK: reparse-issue.h:4:1:{1:1-1:1}: error: a type specifier is required for all declarations
          ^
<stdin>:1:1: note: scanning from here
/Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Index/Inputs/reparse-issue.h:2:1: error: a type specifier is required for all declarations
^
<stdin>:2:83: note: possible intended match here
/Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Index/Inputs/reparse-issue.h:4:1: error: a type specifier is required for all declarations
                                                                                  ^

Input file: <stdin>
Check file: /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Index/reparsed-live-issue.cpp

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

Input was:
<<<<<<
           1: /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Index/Inputs/reparse-issue.h:2:1: error: a type specifier is required for all declarations 
check:4'0     X~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ error: no match found
           2: /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Index/Inputs/reparse-issue.h:4:1: error: a type specifier is required for all declarations 
check:4'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
check:4'1                                                                                       ?                                                                              possible intended match
           3: Number FIX-ITs = 0 
check:4'0     ~~~~~~~~~~~~~~~~~~~
           4: /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Index/reparsed-live-issue.cpp:2:10: note: in file included from /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Index/reparsed-live-issue.cpp:2: 
check:4'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           5: Number FIX-ITs = 0 
check:4'0     ~~~~~~~~~~~~~~~~~~~
>>>>>>

--

********************


```

</details>

https://github.com/llvm/llvm-project/pull/118924