[llvm] InstCombine: Add baseline test for fcmp-0-select combine (PR #172380)

[LLVM Continuous Integration via llvm-commits]

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/34197

<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           : 49146 (97.08%)
  Expectedly Failed:    24 (0.05%)
[1517/1519] Linking CXX executable unittests/Frontend/LLVMFrontendTests
[1518/1519] Running the LLVM regression tests
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/config.py:561: note: using ld.lld: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-1r1yrerd/bin/ld.lld
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/config.py:561: note: using lld-link: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-1r1yrerd/bin/lld-link
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/config.py:561: note: using ld64.lld: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-1r1yrerd/bin/ld64.lld
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/config.py:561: note: using wasm-ld: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-1r1yrerd/bin/wasm-ld
-- Testing: 63792 tests, 60 workers --
Testing:  0.. 10.. 20.. 30.. 40.. 50.. 60.. 70.
FAIL: LLVM :: Transforms/InstCombine/select-fcmp-fmul-zero-absorbing-value.ll (48639 of 63792)
******************** TEST 'LLVM :: Transforms/InstCombine/select-fcmp-fmul-zero-absorbing-value.ll' FAILED ********************
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 2
/var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-1r1yrerd/bin/opt -S -p=instcombine < /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/test/Transforms/InstCombine/select-fcmp-fmul-zero-absorbing-value.ll | /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-1r1yrerd/bin/FileCheck /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/test/Transforms/InstCombine/select-fcmp-fmul-zero-absorbing-value.ll
# executed command: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-1r1yrerd/bin/opt -S -p=instcombine
# executed command: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-1r1yrerd/bin/FileCheck /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/test/Transforms/InstCombine/select-fcmp-fmul-zero-absorbing-value.ll
# .---command stderr------------
# | /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/test/Transforms/InstCombine/select-fcmp-fmul-zero-absorbing-value.ll:376:15: error: CHECK-NEXT: expected string not found in input
# | ; CHECK-NEXT: [[MUL_FABS_X:%.*]] = fmul float [[FABS_X]], 0x4170000000000000
# |               ^
# | <stdin>:179:52: note: scanning from here
# |  %fabs.x = call nnan float @llvm.fabs.f32(float %x)
# |                                                    ^
# | <stdin>:179:52: note: with "FABS_X" equal to "%fabs.x"
# |  %fabs.x = call nnan float @llvm.fabs.f32(float %x)
# |                                                    ^
# | <stdin>:180:21: note: possible intended match here
# |  %mul.fabs.x = fmul nnan float %fabs.x, 0x4170000000000000
# |                     ^
# | 
# | Input file: <stdin>
# | Check file: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/test/Transforms/InstCombine/select-fcmp-fmul-zero-absorbing-value.ll
# | 
# | -dump-input=help explains the following input dump.
# | 
# | Input was:
# | <<<<<<
# |             .
# |             .
# |             .
# |           174:  %select = select i1 %x.is.zero, float %mul.fabs.x, float %fabs.x 
# |           175:  ret float %select 
# |           176: } 
# |           177:  
# |           178: define float @cmp_one_nnan_fabs(float %x) { 
Step 7 (check) failure: check (failure)
...
  Passed           : 49146 (97.08%)
  Expectedly Failed:    24 (0.05%)
[1517/1519] Linking CXX executable unittests/Frontend/LLVMFrontendTests
[1518/1519] Running the LLVM regression tests
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/config.py:561: note: using ld.lld: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-1r1yrerd/bin/ld.lld
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/config.py:561: note: using lld-link: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-1r1yrerd/bin/lld-link
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/config.py:561: note: using ld64.lld: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-1r1yrerd/bin/ld64.lld
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/config.py:561: note: using wasm-ld: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-1r1yrerd/bin/wasm-ld
-- Testing: 63792 tests, 60 workers --
Testing:  0.. 10.. 20.. 30.. 40.. 50.. 60.. 70.
FAIL: LLVM :: Transforms/InstCombine/select-fcmp-fmul-zero-absorbing-value.ll (48639 of 63792)
******************** TEST 'LLVM :: Transforms/InstCombine/select-fcmp-fmul-zero-absorbing-value.ll' FAILED ********************
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 2
/var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-1r1yrerd/bin/opt -S -p=instcombine < /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/test/Transforms/InstCombine/select-fcmp-fmul-zero-absorbing-value.ll | /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-1r1yrerd/bin/FileCheck /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/test/Transforms/InstCombine/select-fcmp-fmul-zero-absorbing-value.ll
# executed command: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-1r1yrerd/bin/opt -S -p=instcombine
# executed command: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-1r1yrerd/bin/FileCheck /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/test/Transforms/InstCombine/select-fcmp-fmul-zero-absorbing-value.ll
# .---command stderr------------
# | /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/test/Transforms/InstCombine/select-fcmp-fmul-zero-absorbing-value.ll:376:15: error: CHECK-NEXT: expected string not found in input
# | ; CHECK-NEXT: [[MUL_FABS_X:%.*]] = fmul float [[FABS_X]], 0x4170000000000000
# |               ^
# | <stdin>:179:52: note: scanning from here
# |  %fabs.x = call nnan float @llvm.fabs.f32(float %x)
# |                                                    ^
# | <stdin>:179:52: note: with "FABS_X" equal to "%fabs.x"
# |  %fabs.x = call nnan float @llvm.fabs.f32(float %x)
# |                                                    ^
# | <stdin>:180:21: note: possible intended match here
# |  %mul.fabs.x = fmul nnan float %fabs.x, 0x4170000000000000
# |                     ^
# | 
# | Input file: <stdin>
# | Check file: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/test/Transforms/InstCombine/select-fcmp-fmul-zero-absorbing-value.ll
# | 
# | -dump-input=help explains the following input dump.
# | 
# | Input was:
# | <<<<<<
# |             .
# |             .
# |             .
# |           174:  %select = select i1 %x.is.zero, float %mul.fabs.x, float %fabs.x 
# |           175:  ret float %select 
# |           176: } 
# |           177:  
# |           178: define float @cmp_one_nnan_fabs(float %x) { 

```

</details>

https://github.com/llvm/llvm-project/pull/172380