[llvm] [BOLT][AArch64] Run LDR relaxation (PR #165787)

[YongKang Zhu via llvm-commits]

yozhu wrote:

> but I would prefer to call the instructions more general isLoadLiteral or something else instead isLDRX/Wl 

Thanks for the review!

I didn't use a more general name like `isLoadLiteral()` because for now we only handle two types of load literal instructions (mentioned in the TODO comment in `AArch64RelaxationPass::runOnFunction()`):

```
ldr Xt, [label]
ldr Wt, [label]
```

while `isLoadLiteral()` would cover all variants of LDR load literal instructions.

https://github.com/llvm/llvm-project/pull/165787