[llvm] Fix GenericFloatingPointPredicateUtils (PR #141258)

[Steven Wu via llvm-commits]

cachemeifyoucan wrote:

Bot is hitting a different error now: https://green.lab.llvm.org/job/llvm.org/job/clang-stage2-Rthinlto/769/console

```
22:32:01 
 /Users/ec2-user/jenkins/workspace/llvm.org/clang-stage2-Rthinlto/llvm-project/llvm/lib/CodeGen/GlobalISel/MachineFloatingPointPredicateUtils.cpp:23:37: error: explicit specialization of 'queryDenormalMode' after instantiation
22:32:01     23 | MachineFloatingPointPredicateUtils::queryDenormalMode(const MachineFunction &MF,
22:32:01        |                                     ^
22:32:01  /Users/ec2-user/jenkins/workspace/llvm.org/clang-stage2-Rthinlto/llvm-project/llvm/include/llvm/IR/GenericFloatingPointPredicateUtils.h:132:27: note: implicit instantiation first required here
22:32:01    132 |       DenormalMode Mode = queryDenormalMode(F, LHS);
22:32:01        |                           ^
22:32:01  /Users/ec2-user/jenkins/workspace/llvm.org/clang-stage2-Rthinlto/llvm-project/llvm/lib/CodeGen/GlobalISel/MachineFloatingPointPredicateUtils.cpp:31:42: error: explicit specialization of 'lookThroughFAbs' after instantiation
22:32:01     31 | bool MachineFloatingPointPredicateUtils::lookThroughFAbs(
22:32:01        |                                          ^
22:32:01  /Users/ec2-user/jenkins/workspace/llvm.org/clang-stage2-Rthinlto/llvm-project/llvm/include/llvm/IR/GenericFloatingPointPredicateUtils.h:421:45: note: implicit instantiation first required here
22:32:01    421 |       const bool IsFabs = LookThroughSrc && lookThroughFAbs(F, LHS, Src);
22:32:01        |                                             ^
22:32:01  /Users/ec2-user/jenkins/workspace/llvm.org/clang-stage2-Rthinlto/llvm-project/llvm/lib/CodeGen/GlobalISel/MachineFloatingPointPredicateUtils.cpp:38:60: error: explicit specialization of 'matchConstantFloat' after instantiation
22:32:01     38 | std::optional<APFloat> MachineFloatingPointPredicateUtils::matchConstantFloat(
22:32:01        |                                                            ^
22:32:01  /Users/ec2-user/jenkins/workspace/llvm.org/clang-stage2-Rthinlto/llvm-project/llvm/include/llvm/IR/GenericFloatingPointPredicateUtils.h:468:39: note: implicit instantiation first required here
22:32:01    468 |     std::optional<APFloat> ConstRHS = matchConstantFloat(F, RHS);
22:32:01        |                                       ^
22:32:01  3 errors generated.

```


https://github.com/llvm/llvm-project/pull/141258