[llvm] [InstSimplify] Add basic constant folding for `llvm.sincos` (PR #114527)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-clang-x86_64-sie-win` running on `sie-win-worker` while building `llvm` at step 7 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/46/builds/9157

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

```
Step 7 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'LLVM :: Transforms/InstSimplify/sincos.ll' FAILED ********************
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 1
z:\b\llvm-clang-x86_64-sie-win\build\bin\opt.exe -S -passes=instsimplify Z:\b\llvm-clang-x86_64-sie-win\llvm-project\llvm\test\Transforms\InstSimplify\sincos.ll | z:\b\llvm-clang-x86_64-sie-win\build\bin\filecheck.exe Z:\b\llvm-clang-x86_64-sie-win\llvm-project\llvm\test\Transforms\InstSimplify\sincos.ll
# executed command: 'z:\b\llvm-clang-x86_64-sie-win\build\bin\opt.exe' -S -passes=instsimplify 'Z:\b\llvm-clang-x86_64-sie-win\llvm-project\llvm\test\Transforms\InstSimplify\sincos.ll'
# executed command: 'z:\b\llvm-clang-x86_64-sie-win\build\bin\filecheck.exe' 'Z:\b\llvm-clang-x86_64-sie-win\llvm-project\llvm\test\Transforms\InstSimplify\sincos.ll'
# .---command stderr------------
# | Z:\b\llvm-clang-x86_64-sie-win\llvm-project\llvm\test\Transforms\InstSimplify\sincos.ll:45:15: error: CHECK-NEXT: expected string not found in input
# | ; CHECK-NEXT: ret { <2 x float>, <2 x float> } { <2 x float> zeroinitializer, <2 x float> <float 1.000000e+00, float 1.000000e+00> }
# |               ^
# | <stdin>:24:60: note: scanning from here
# | define { <2 x float>, <2 x float> } @sincos_zero_vector() {
# |                                                            ^
# | <stdin>:25:2: note: possible intended match here
# |  ret { <2 x float>, <2 x float> } { <2 x float> zeroinitializer, <2 x float> splat (float 1.000000e+00) }
# |  ^
# | 
# | Input file: <stdin>
# | Check file: Z:\b\llvm-clang-x86_64-sie-win\llvm-project\llvm\test\Transforms\InstSimplify\sincos.ll
# | 
# | -dump-input=help explains the following input dump.
# | 
# | Input was:
# | <<<<<<
# |              1: ; ModuleID = 'Z:\b\llvm-clang-x86_64-sie-win\llvm-project\llvm\test\Transforms\InstSimplify\sincos.ll' 
# |              2: source_filename = "Z:\\b\\llvm-clang-x86_64-sie-win\\llvm-project\\llvm\\test\\Transforms\\InstSimplify\\sincos.ll" 
# |              3:  
# |              4: define { float, float } @sincos_zero() { 
# | label:4'0       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# | label:4'1       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# |              5:  ret { float, float } { float 0.000000e+00, float 1.000000e+00 } 
# | next:5           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# |              6: } 
# |              7:  
# |              8: define { float, float } @sincos_neg_zero() { 
# | label:12'0      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# | label:12'1      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# |              9:  ret { float, float } { float -0.000000e+00, float 1.000000e+00 } 
# | next:13          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# |             10: } 
# |             11:  
# |             12: define { float, float } @sincos_one() { 
# | label:20'0      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# | label:20'1      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# |             13:  ret { float, float } { float 0x3FEAED5480000000, float 0x3FE14A2800000000 } 
# | next:21'0        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# | next:21'1                                     ^~~~~~~~~~~~~~~~~~                              captured var "$SIN_ONE"
...

```

</details>

https://github.com/llvm/llvm-project/pull/114527