[llvm] [ConstantFolding] Consider `tanh*` to always be a noop (PR #70794)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-clang-x86_64-sie-ubuntu-fast` running on `sie-linux-worker` while building `llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/144/builds/48474

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

```
Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'LLVM :: Transforms/EarlyCSE/math-1.ll' FAILED ********************
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 2
/home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/bin/opt -passes=early-cse -earlycse-debug-hash -S -o - /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/llvm/test/Transforms/EarlyCSE/math-1.ll | /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/bin/FileCheck /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/llvm/test/Transforms/EarlyCSE/math-1.ll
# executed command: /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/bin/opt -passes=early-cse -earlycse-debug-hash -S -o - /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/llvm/test/Transforms/EarlyCSE/math-1.ll
# note: command had no output on stdout or stderr
# executed command: /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/bin/FileCheck /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/llvm/test/Transforms/EarlyCSE/math-1.ll
# .---command stderr------------
# | /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/llvm/test/Transforms/EarlyCSE/math-1.ll:189:15: error: CHECK-NEXT: expected string not found in input
# | ; CHECK-NEXT: [[RES:%.*]] = tail call fast float @tanhf(float 1.000000e+00)
# |               ^
# | <stdin>:148:23: note: scanning from here
# | define float @f_tanhf() {
# |                       ^
# | <stdin>:149:2: note: possible intended match here
# |  ret float 0x3FE85EFAC0000000
# |  ^
# | 
# | Input file: <stdin>
# | Check file: /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/llvm/test/Transforms/EarlyCSE/math-1.ll
# | 
# | -dump-input=help explains the following input dump.
# | 
# | Input was:
# | <<<<<<
# |              1: ; ModuleID = '/home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/llvm/test/Transforms/EarlyCSE/math-1.ll' 
# |              2: source_filename = "/home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/llvm/test/Transforms/EarlyCSE/math-1.ll" 
# |              3:  
# |              4: ; Function Attrs: nofree nounwind willreturn 
# |              5: declare double @acos(double) #0 
# |              6:  
# |              7: define double  at f_acos() { 
# | label:6'0                     ^~~~~~~~
# | label:6'1                     ^~~~~~~~
# |              8:  ret double 0.000000e+00 
# | next:7           ^~~~~~~~~~~~~~~~~~~~~~~
# |              9: } 
# |             10:  
# |             11: ; Function Attrs: nofree nounwind willreturn 
# |             12: declare float @asinf(float) #0 
# |             13:  
# |             14: define float  at f_asinf() { 
# | label:15'0                   ^~~~~~~~~
# | label:15'1                   ^~~~~~~~~
# |             15:  ret float 0x3FF921FB60000000 
# | next:16          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
# |             16: } 
...

```

</details>

https://github.com/llvm/llvm-project/pull/70794