[llvm] [PassBuilder][FatLTO] Expose FatLTO pipeline via pipeline string (PR #146048)

[Mikael Holmén via llvm-commits]

mikaelholmen wrote:

With EXPENSIVE_CHECKS the fatlto.ll testcase fails because there is an unexpected
```Running analysis: PreservedModuleHashAnalysis on [module]```.
We get
```
test/Other/fatlto.ll:7:15: error: CHECK-NEXT: is not on the line after the previous match
; CHECK-NEXT: Running pass: LowerTypeTestsPass on [module]
              ^
<stdin>:41:1: note: 'next' match was here
Running pass: LowerTypeTestsPass on [module]
^
<stdin>:39:40: note: previous match ended here
Running pass: FatLtoCleanup on [module]
                                       ^
<stdin>:40:1: note: non-matching line after previous match is here
Running analysis: PreservedModuleHashAnalysis on [module]
^

Input file: <stdin>
Check file: test/Other/fatlto.ll

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

Input was:
<<<<<<
        .
        .
        .
       36: Invalidating analysis: LazyCallGraphAnalysis on [module] 
       37: Invalidating analysis: InnerAnalysisManagerProxy<CGSCCAnalysisManager, Module> on [module] 
       38: Running analysis: InnerAnalysisManagerProxy<FunctionAnalysisManager, Module> on [module] 
       39: Running pass: FatLtoCleanup on [module] 
       40: Running analysis: PreservedModuleHashAnalysis on [module] 
       41: Running pass: LowerTypeTestsPass on [module] 
next:7     !~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  error: match on wrong line
       42: Running pass: EliminateAvailableExternallyPass on [module] 
       43: Running pass: ReversePostOrderFunctionAttrsPass on [module] 
       44: Running analysis: LazyCallGraphAnalysis on [module] 
       45: Running pass: RecomputeGlobalsAAPass on [module] 
       46: Running analysis: CallGraphAnalysis on [module] 
        .
        .
        .
>>>>>>
```
I suppose a bit more relaxation is needed.

https://github.com/llvm/llvm-project/pull/146048