[llvm] [InstCombine] Simplify fractions when there is no overflow (PR #210516)

Sat Aug 8 11:47:28 PDT 2026

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `sanitizer-x86_64-linux-qemu` running on `sanitizer-buildbot4` while building `llvm` at step 2 "annotate".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/139/builds/35995

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

```
Step 2 (annotate) failure: 'python ../sanitizer_buildbot/sanitizers/zorg/buildbot/builders/sanitizers/buildbot_selector.py' (failure)
...
[74/80] Generating ScudoUnitTestsObjects.primary_test.cpp.x86_64.o
[75/80] Generating ScudoUnitTestsObjects.gtest-all.cc.x86_64.o
[76/80] Generating ScudoCxxUnitTest-x86_64-Test
[77/80] Generating ScudoCUnitTest-x86_64-Test
[78/80] Generating ScudoUnitTestsObjects.combined_test.cpp.x86_64.o
[79/80] Generating ScudoUnitTest-x86_64-Test
[79/80] Running Scudo Standalone tests
-- Testing: 244 tests, 64 workers --
Testing:  0.. 10.. 20.. 30.. 40.. 50.. 60.. 70.. 80.. 90..
TIMEOUT: ScudoStandalone-Unit :: ./ScudoUnitTest-x86_64-Test/54/95 (244 of 244)
******************** TEST 'ScudoStandalone-Unit :: ./ScudoUnitTest-x86_64-Test/54/95' FAILED ********************
Script(shard):
--
GTEST_OUTPUT=json:/home/b/sanitizer-x86_64-linux-qemu/build/llvm_build2_x86_64_qemu/lib/scudo/standalone/tests/./ScudoUnitTest-x86_64-Test-ScudoStandalone-Unit-3138745-54-95.json GTEST_SHUFFLE=0 GTEST_TOTAL_SHARDS=95 GTEST_SHARD_INDEX=54 /home/b/sanitizer-x86_64-linux-qemu/build/qemu_build/qemu-x86_64 -L /usr/x86_64-linux-gnu /home/b/sanitizer-x86_64-linux-qemu/build/llvm_build2_x86_64_qemu/lib/scudo/standalone/tests/./ScudoUnitTest-x86_64-Test
--

Note: This is test shard 55 of 95.
[==========] Running 4 tests from 4 test suites.
[----------] Global test environment set-up.
[----------] 1 test from ScudoCombinedDeathTestBasicCombined5_DefaultConfig
[ RUN      ] ScudoCombinedDeathTestBasicCombined5_DefaultConfig.BasicCombined5
[       OK ] ScudoCombinedDeathTestBasicCombined5_DefaultConfig.BasicCombined5 (73 ms)
[----------] 1 test from ScudoCombinedDeathTestBasicCombined5_DefaultConfig (80 ms total)

[----------] 1 test from ScudoCombinedDeathTestReallocateDecreasingTagged_TestNoCacheConfig
[ RUN      ] ScudoCombinedDeathTestReallocateDecreasingTagged_TestNoCacheConfig.ReallocateDecreasingTagged
/home/b/sanitizer-x86_64-linux-qemu/build/llvm-project/compiler-rt/lib/scudo/standalone/tests/combined_test.cpp:515: Skipped
Requires MTE

[  SKIPPED ] ScudoCombinedDeathTestReallocateDecreasingTagged_TestNoCacheConfig.ReallocateDecreasingTagged (13 ms)
[----------] 1 test from ScudoCombinedDeathTestReallocateDecreasingTagged_TestNoCacheConfig (13 ms total)

[----------] 1 test from ScudoCombinedTestAllocAfterFork_DefaultConfig
[ RUN      ] ScudoCombinedTestAllocAfterFork_DefaultConfig.AllocAfterFork

--
exit: -9
--
Reached timeout of 900 seconds
********************
Testing:  0.. 10.. 20.. 30.. 40.. 50.. 60.. 70.. 80.. 90.. 
Slowest Tests (20 of 758):
--------------------------------------------------------------------------
900.08s: ScudoStandalone-Unit :: ./ScudoUnitTest-x86_64-Test/54/95
58.19s: ScudoStandalone-Unit :: ./ScudoUnitTest-x86_64-Test/ScudoCombinedTestDisableMemInit_DefaultConfig/DisableMemInit
57.17s: ScudoStandalone-Unit-GwpAsanTorture :: ./ScudoUnitTest-x86_64-Test/ScudoCombinedTestDisableMemInit_DefaultConfig/DisableMemInit
41.95s: ScudoStandalone-Unit :: ./ScudoUnitTest-x86_64-Test/ScudoCombinedTestDisableMemInit_TestNoCacheConfig/DisableMemInit
41.46s: ScudoStandalone-Unit-GwpAsanTorture :: ./ScudoUnitTest-x86_64-Test/ScudoCombinedTestDisableMemInit_TestNoCacheConfig/DisableMemInit
40.70s: ScudoStandalone-Unit-GwpAsanTorture :: ./ScudoUnitTest-x86_64-Test/ScudoCombinedTestDisableMemInit_AndroidConfig/DisableMemInit
Step 12 (scudo x86_64_qemu) failure: scudo x86_64_qemu (failure)
...
[74/80] Generating ScudoUnitTestsObjects.primary_test.cpp.x86_64.o
[75/80] Generating ScudoUnitTestsObjects.gtest-all.cc.x86_64.o
[76/80] Generating ScudoCxxUnitTest-x86_64-Test
[77/80] Generating ScudoCUnitTest-x86_64-Test
[78/80] Generating ScudoUnitTestsObjects.combined_test.cpp.x86_64.o
[79/80] Generating ScudoUnitTest-x86_64-Test
[79/80] Running Scudo Standalone tests
-- Testing: 244 tests, 64 workers --
Testing:  0.. 10.. 20.. 30.. 40.. 50.. 60.. 70.. 80.. 90..
TIMEOUT: ScudoStandalone-Unit :: ./ScudoUnitTest-x86_64-Test/54/95 (244 of 244)
******************** TEST 'ScudoStandalone-Unit :: ./ScudoUnitTest-x86_64-Test/54/95' FAILED ********************
Script(shard):
--
GTEST_OUTPUT=json:/home/b/sanitizer-x86_64-linux-qemu/build/llvm_build2_x86_64_qemu/lib/scudo/standalone/tests/./ScudoUnitTest-x86_64-Test-ScudoStandalone-Unit-3138745-54-95.json GTEST_SHUFFLE=0 GTEST_TOTAL_SHARDS=95 GTEST_SHARD_INDEX=54 /home/b/sanitizer-x86_64-linux-qemu/build/qemu_build/qemu-x86_64 -L /usr/x86_64-linux-gnu /home/b/sanitizer-x86_64-linux-qemu/build/llvm_build2_x86_64_qemu/lib/scudo/standalone/tests/./ScudoUnitTest-x86_64-Test
--

Note: This is test shard 55 of 95.
[==========] Running 4 tests from 4 test suites.
[----------] Global test environment set-up.
[----------] 1 test from ScudoCombinedDeathTestBasicCombined5_DefaultConfig
[ RUN      ] ScudoCombinedDeathTestBasicCombined5_DefaultConfig.BasicCombined5
[       OK ] ScudoCombinedDeathTestBasicCombined5_DefaultConfig.BasicCombined5 (73 ms)
[----------] 1 test from ScudoCombinedDeathTestBasicCombined5_DefaultConfig (80 ms total)

[----------] 1 test from ScudoCombinedDeathTestReallocateDecreasingTagged_TestNoCacheConfig
[ RUN      ] ScudoCombinedDeathTestReallocateDecreasingTagged_TestNoCacheConfig.ReallocateDecreasingTagged
/home/b/sanitizer-x86_64-linux-qemu/build/llvm-project/compiler-rt/lib/scudo/standalone/tests/combined_test.cpp:515: Skipped
Requires MTE

[  SKIPPED ] ScudoCombinedDeathTestReallocateDecreasingTagged_TestNoCacheConfig.ReallocateDecreasingTagged (13 ms)
[----------] 1 test from ScudoCombinedDeathTestReallocateDecreasingTagged_TestNoCacheConfig (13 ms total)

[----------] 1 test from ScudoCombinedTestAllocAfterFork_DefaultConfig
[ RUN      ] ScudoCombinedTestAllocAfterFork_DefaultConfig.AllocAfterFork

--
exit: -9
--
Reached timeout of 900 seconds
********************
Testing:  0.. 10.. 20.. 30.. 40.. 50.. 60.. 70.. 80.. 90.. 
Slowest Tests (20 of 758):
--------------------------------------------------------------------------
900.08s: ScudoStandalone-Unit :: ./ScudoUnitTest-x86_64-Test/54/95
58.19s: ScudoStandalone-Unit :: ./ScudoUnitTest-x86_64-Test/ScudoCombinedTestDisableMemInit_DefaultConfig/DisableMemInit
57.17s: ScudoStandalone-Unit-GwpAsanTorture :: ./ScudoUnitTest-x86_64-Test/ScudoCombinedTestDisableMemInit_DefaultConfig/DisableMemInit
41.95s: ScudoStandalone-Unit :: ./ScudoUnitTest-x86_64-Test/ScudoCombinedTestDisableMemInit_TestNoCacheConfig/DisableMemInit
41.46s: ScudoStandalone-Unit-GwpAsanTorture :: ./ScudoUnitTest-x86_64-Test/ScudoCombinedTestDisableMemInit_TestNoCacheConfig/DisableMemInit
40.70s: ScudoStandalone-Unit-GwpAsanTorture :: ./ScudoUnitTest-x86_64-Test/ScudoCombinedTestDisableMemInit_AndroidConfig/DisableMemInit

```

</details>

https://github.com/llvm/llvm-project/pull/210516