[llvm] [LoongArch] Add late branch optimisation pass (PR #168516)

[via llvm-commits]

github-actions[bot] wrote:

<!--PREMERGE ADVISOR COMMENT: Linux-->
# :penguin: Linux x64 Test Results

* 166070 tests passed
* 2834 tests skipped
* 1 test failed

## Failed Tests
(click on a test name to see its output)

### LLVM
<details>
<summary>LLVM.tools/UpdateTestChecks/update_llc_test_checks/loongarch_generated_funcs.test</summary>

```
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 4
cp -f /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/test/tools/UpdateTestChecks/update_llc_test_checks/Inputs/loongarch_generated_funcs.ll /home/gha/actions-runner/_work/llvm-project/llvm-project/build/test/tools/UpdateTestChecks/update_llc_test_checks/Output/loongarch_generated_funcs.test.tmp.ll && '/usr/bin/python3' /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/utils/update_llc_test_checks.py --llc-binary /home/gha/actions-runner/_work/llvm-project/llvm-project/build/bin/llc --version=1 --include-generated-funcs /home/gha/actions-runner/_work/llvm-project/llvm-project/build/test/tools/UpdateTestChecks/update_llc_test_checks/Output/loongarch_generated_funcs.test.tmp.ll
# executed command: cp -f /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/test/tools/UpdateTestChecks/update_llc_test_checks/Inputs/loongarch_generated_funcs.ll /home/gha/actions-runner/_work/llvm-project/llvm-project/build/test/tools/UpdateTestChecks/update_llc_test_checks/Output/loongarch_generated_funcs.test.tmp.ll
# note: command had no output on stdout or stderr
# executed command: /usr/bin/python3 /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/utils/update_llc_test_checks.py --llc-binary /home/gha/actions-runner/_work/llvm-project/llvm-project/build/bin/llc --version=1 --include-generated-funcs /home/gha/actions-runner/_work/llvm-project/llvm-project/build/test/tools/UpdateTestChecks/update_llc_test_checks/Output/loongarch_generated_funcs.test.tmp.ll
# .---command stderr------------
# | warning: 'ilp32s' has not been standardized
# `-----------------------------
# RUN: at line 5
diff -u /home/gha/actions-runner/_work/llvm-project/llvm-project/build/test/tools/UpdateTestChecks/update_llc_test_checks/Output/loongarch_generated_funcs.test.tmp.ll /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/test/tools/UpdateTestChecks/update_llc_test_checks/Inputs/loongarch_generated_funcs.ll.generated.expected
# executed command: diff -u /home/gha/actions-runner/_work/llvm-project/llvm-project/build/test/tools/UpdateTestChecks/update_llc_test_checks/Output/loongarch_generated_funcs.test.tmp.ll /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/test/tools/UpdateTestChecks/update_llc_test_checks/Inputs/loongarch_generated_funcs.ll.generated.expected
# .---command stdout------------
# | --- /home/gha/actions-runner/_work/llvm-project/llvm-project/build/test/tools/UpdateTestChecks/update_llc_test_checks/Output/loongarch_generated_funcs.test.tmp.ll
# | +++ /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/test/tools/UpdateTestChecks/update_llc_test_checks/Inputs/loongarch_generated_funcs.ll.generated.expected
# | @@ -75,7 +75,7 @@
# |  ; CHECK-NEXT:    st.w $zero, $fp, -12
# |  ; CHECK-NEXT:    st.w $zero, $fp, -16
# |  ; CHECK-NEXT:    ori $a0, $zero, 1
# | -; CHECK-NEXT:    b .LBB0_3
# | +; CHECK-NEXT:    beq $zero, $zero, .LBB0_3
# |  ; CHECK-NEXT:  # %bb.1:
# |  ; CHECK-NEXT:    st.w $a0, $fp, -24
# |  ; CHECK-NEXT:    ld.w $a0, $fp, -16
# `-----------------------------
# error: command failed with exit status: 1

--

```
</details>

If these failures are unrelated to your changes (for example tests are broken or flaky at HEAD), please open an issue at https://github.com/llvm/llvm-project/issues and add the `infrastructure` label.

https://github.com/llvm/llvm-project/pull/168516