[llvm] [NFC][AMDGPU][Attributor] Exit earlier if entry CC (PR #114177)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `openmp-offload-sles-build-only` running on `rocm-worker-hw-04-sles` while building `llvm` at step 8 "Add check check-llvm".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/140/builds/9732

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

```
Step 8 (Add check check-llvm) failure: test (failure)
******************** TEST 'LLVM :: CodeGen/AMDGPU/attributor-loop-issue-58639.ll' FAILED ********************
Exit Code: 1

Command Output (stderr):
--
RUN: at line 2: /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.build/bin/opt -S -mtriple=amdgcn-amd-amdhsa -passes=amdgpu-attributor /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.src/llvm/test/CodeGen/AMDGPU/attributor-loop-issue-58639.ll | /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.build/bin/FileCheck /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.src/llvm/test/CodeGen/AMDGPU/attributor-loop-issue-58639.ll
+ /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.build/bin/opt -S -mtriple=amdgcn-amd-amdhsa -passes=amdgpu-attributor /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.src/llvm/test/CodeGen/AMDGPU/attributor-loop-issue-58639.ll
+ /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.build/bin/FileCheck /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.src/llvm/test/CodeGen/AMDGPU/attributor-loop-issue-58639.ll
/home/botworker/bbot/builds/openmp-offload-sles-build/llvm.src/llvm/test/CodeGen/AMDGPU/attributor-loop-issue-58639.ll:54:15: error: CHECK-SAME: expected string not found in input
; CHECK-SAME: () #[[ATTR0]] {
              ^
<stdin>:32:33: note: scanning from here
define amdgpu_kernel void @entry() #1 {
                                ^
<stdin>:32:33: note: with "ATTR0" equal to "0"
define amdgpu_kernel void @entry() #1 {
                                ^

Input file: <stdin>
Check file: /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.src/llvm/test/CodeGen/AMDGPU/attributor-loop-issue-58639.ll

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

Input was:
<<<<<<
           .
           .
           .
          27:  %tmp6 = load ptr, ptr %tmp4, align 8 
          28:  %tmp7 = call fastcc i1 @widget(ptr %tmp6) 
          29:  br label %bb5 
          30: } 
          31:  
          32: define amdgpu_kernel void @entry() #1 { 
same:54'0                                     X~~~~~~~ error: no match found
same:54'1                                              with "ATTR0" equal to "0"
          33:  %alloca = alloca %0, align 8, addrspace(5) 
same:54'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
          34:  %cast = addrspacecast ptr addrspace(5) %alloca to ptr 
same:54'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
          35:  %arst = call double @baz(ptr %cast) 
same:54'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
          36:  ret void 
same:54'0     ~~~~~~~~~~
          37: } 
same:54'0     ~~
           .
           .
           .
>>>>>>
...

```

</details>

https://github.com/llvm/llvm-project/pull/114177