[llvm] [RISCV] GISel custom lowering for G_ADD/G_SUB (PR #121587)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `lldb-aarch64-ubuntu` running on `linaro-lldb-aarch64-ubuntu` while building `llvm` at step 6 "test".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/59/builds/10719

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

```
Step 6 (test) failure: build (failure)
...
PASS: lldb-api :: terminal/TestSTTYBeforeAndAfter.py (1113 of 2064)
PASS: lldb-api :: test_utils/TestDecorators.py (1114 of 2064)
PASS: lldb-api :: test_utils/TestInlineTest.py (1115 of 2064)
PASS: lldb-api :: symbol_ondemand/shared_library/TestSharedLibOnDemand.py (1116 of 2064)
PASS: lldb-api :: test_utils/TestPExpectTest.py (1117 of 2064)
PASS: lldb-api :: test_utils/base/TestBaseTest.py (1118 of 2064)
PASS: lldb-api :: source-manager/TestSourceManager.py (1119 of 2064)
UNSUPPORTED: lldb-api :: tools/lldb-dap/breakpoint-events/TestDAP_breakpointEvents.py (1120 of 2064)
PASS: lldb-api :: python_api/watchpoint/watchlocation/TestSetWatchlocation.py (1121 of 2064)
PASS: lldb-api :: python_api/watchpoint/watchlocation/TestTargetWatchAddress.py (1122 of 2064)
FAIL: lldb-api :: tools/lldb-dap/attach/TestDAP_attachByPortNum.py (1123 of 2064)
******************** TEST 'lldb-api :: tools/lldb-dap/attach/TestDAP_attachByPortNum.py' FAILED ********************
Script:
--
/usr/bin/python3.10 /home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/llvm-project/lldb/test/API/dotest.py -u CXXFLAGS -u CFLAGS --env LLVM_LIBS_DIR=/home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/./lib --env LLVM_INCLUDE_DIR=/home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/include --env LLVM_TOOLS_DIR=/home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/./bin --arch aarch64 --build-dir /home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/lldb-test-build.noindex --lldb-module-cache-dir /home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/lldb-test-build.noindex/module-cache-lldb/lldb-api --clang-module-cache-dir /home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/lldb-test-build.noindex/module-cache-clang/lldb-api --executable /home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/./bin/lldb --compiler /home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/./bin/clang --dsymutil /home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/./bin/dsymutil --make /usr/bin/gmake --llvm-tools-dir /home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/./bin --lldb-obj-root /home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/tools/lldb --lldb-libs-dir /home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/./lib /home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/llvm-project/lldb/test/API/tools/lldb-dap/attach -p TestDAP_attachByPortNum.py
--
Exit Code: 1

Command Output (stdout):
--
lldb version 20.0.0git (https://github.com/llvm/llvm-project.git revision dde5546b79f784ab71cac325e0a0698c67c4dcde)
  clang revision dde5546b79f784ab71cac325e0a0698c67c4dcde
  llvm revision dde5546b79f784ab71cac325e0a0698c67c4dcde
Skipping the following test categories: ['libc++', 'dsym', 'gmodules', 'debugserver', 'objc']
========= DEBUG ADAPTER PROTOCOL LOGS =========
1736305496.398362398 --> 
Content-Length: 343

{
  "arguments": {
    "adapterID": "lldb-native",
    "clientID": "vscode",
    "columnsStartAt1": true,
    "linesStartAt1": true,
    "locale": "en-us",
    "pathFormat": "path",
    "sourceInitFile": true,
    "supportsRunInTerminalRequest": true,
    "supportsStartDebuggingRequest": true,
    "supportsVariablePaging": true,
    "supportsVariableType": true
  },
  "command": "initialize",
  "seq": 1,
  "type": "request"
}
1736305496.400357962 <-- 
Content-Length: 1589


```

</details>

https://github.com/llvm/llvm-project/pull/121587