[llvm] [AArch64] Improve lowering of scalar abs(sub(a, b)). (PR #151180)

Wed Aug 6 05:22:40 PDT 2025

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `fuchsia-x86_64-linux` running on `fuchsia-debian-64-us-central1-a-1` while building `llvm` at step 4 "annotate".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/11/builds/21225

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

```
Step 4 (annotate) failure: 'python ../llvm-zorg/zorg/buildbot/builders/annotated/fuchsia-linux.py ...' (failure)
...
  Passed           : 46762 (97.71%)
  Expectedly Failed:    26 (0.05%)
[1394/1396] Linking CXX executable unittests/tools/llvm-exegesis/LLVMExegesisTests
[1395/1396] Running the LLVM regression tests
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/config.py:520: note: using ld.lld: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-o27g1628/bin/ld.lld
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/config.py:520: note: using lld-link: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-o27g1628/bin/lld-link
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/config.py:520: note: using ld64.lld: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-o27g1628/bin/ld64.lld
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/config.py:520: note: using wasm-ld: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-o27g1628/bin/wasm-ld
-- Testing: 60512 tests, 60 workers --
Testing:  0.
FAIL: LLVM :: CodeGen/AArch64/midpoint-int.ll (4394 of 60512)
******************** TEST 'LLVM :: CodeGen/AArch64/midpoint-int.ll' FAILED ********************
Exit Code: 1

Command Output (stderr):
--
/var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-o27g1628/bin/llc -mtriple=aarch64-unknown-linux-gnu < /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/test/CodeGen/AArch64/midpoint-int.ll | /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-o27g1628/bin/FileCheck /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/test/CodeGen/AArch64/midpoint-int.ll # RUN: at line 2
+ /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-o27g1628/bin/llc -mtriple=aarch64-unknown-linux-gnu
+ /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-o27g1628/bin/FileCheck /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/test/CodeGen/AArch64/midpoint-int.ll
/var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/test/CodeGen/AArch64/midpoint-int.ll:304:15: error: CHECK-NEXT: expected string not found in input
; CHECK-NEXT: sxth w9, w1
              ^
<stdin>:197:10: note: scanning from here
// %bb.0:
         ^
<stdin>:200:7: note: possible intended match here
 subs w10, w9, w1, sxth
      ^
/var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/test/CodeGen/AArch64/midpoint-int.ll:429:15: error: CHECK-NEXT: expected string not found in input
; CHECK-NEXT: sxtb w9, w1
              ^
<stdin>:279:10: note: scanning from here
// %bb.0:
         ^
<stdin>:282:7: note: possible intended match here
 subs w10, w9, w1, sxtb
      ^

Input file: <stdin>
Check file: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/test/CodeGen/AArch64/midpoint-int.ll

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

Input was:
<<<<<<
            .
            .
            .
          192:  // -- End function 
Step 7 (check) failure: check (failure)
...
  Passed           : 46762 (97.71%)
  Expectedly Failed:    26 (0.05%)
[1394/1396] Linking CXX executable unittests/tools/llvm-exegesis/LLVMExegesisTests
[1395/1396] Running the LLVM regression tests
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/config.py:520: note: using ld.lld: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-o27g1628/bin/ld.lld
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/config.py:520: note: using lld-link: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-o27g1628/bin/lld-link
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/config.py:520: note: using ld64.lld: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-o27g1628/bin/ld64.lld
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/config.py:520: note: using wasm-ld: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-o27g1628/bin/wasm-ld
-- Testing: 60512 tests, 60 workers --
Testing:  0.
FAIL: LLVM :: CodeGen/AArch64/midpoint-int.ll (4394 of 60512)
******************** TEST 'LLVM :: CodeGen/AArch64/midpoint-int.ll' FAILED ********************
Exit Code: 1

Command Output (stderr):
--
/var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-o27g1628/bin/llc -mtriple=aarch64-unknown-linux-gnu < /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/test/CodeGen/AArch64/midpoint-int.ll | /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-o27g1628/bin/FileCheck /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/test/CodeGen/AArch64/midpoint-int.ll # RUN: at line 2
+ /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-o27g1628/bin/llc -mtriple=aarch64-unknown-linux-gnu
+ /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-o27g1628/bin/FileCheck /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/test/CodeGen/AArch64/midpoint-int.ll
/var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/test/CodeGen/AArch64/midpoint-int.ll:304:15: error: CHECK-NEXT: expected string not found in input
; CHECK-NEXT: sxth w9, w1
              ^
<stdin>:197:10: note: scanning from here
// %bb.0:
         ^
<stdin>:200:7: note: possible intended match here
 subs w10, w9, w1, sxth
      ^
/var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/test/CodeGen/AArch64/midpoint-int.ll:429:15: error: CHECK-NEXT: expected string not found in input
; CHECK-NEXT: sxtb w9, w1
              ^
<stdin>:279:10: note: scanning from here
// %bb.0:
         ^
<stdin>:282:7: note: possible intended match here
 subs w10, w9, w1, sxtb
      ^

Input file: <stdin>
Check file: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/test/CodeGen/AArch64/midpoint-int.ll

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

Input was:
<<<<<<
            .
            .
            .
          192:  // -- End function 

```

</details>

https://github.com/llvm/llvm-project/pull/151180