[llvm] [TLI] Add getLibFunc in TLI API that accepts an Instruction. (PR #75919)

[Alexandros Lamprineas via llvm-commits]

================
@@ -1149,6 +1149,20 @@ bool TargetLibraryInfoImpl::getLibFunc(const Function &FDecl,
   return isValidProtoForLibFunc(*FDecl.getFunctionType(), F, *M);
 }
 
+bool TargetLibraryInfoImpl::getLibFunc(const Instruction &I, LibFunc &F) const {
+  if (I.getOpcode() != Instruction::FRem)
+    return false;
+
----------------
labrinea wrote:

I would write it as
```
Type *ScalarTy = I.getType()->getScalarType();

if (!ScalarTy->isDoubleTy() && !ScalarTy->isFloatTy())
  return false;

F = ScalarTy->isDoubleTy() ? LibFunc_fmod : LibFunc_fmodf;
return true;
```

https://github.com/llvm/llvm-project/pull/75919