[llvm] [LTO] Run Argument Promotion before IPSCCP (PR #111163)

[Hari Limaye via llvm-commits]

hazzlim wrote:

> A question I have here if this problem is somehow specific to LTO, or whether you just happen to be optimizing for LTO?

It looks like it would be more expensive to do this non-LTO. The results I got for CTMark at O3 (non-LTO) on AArch64:
```

Benchmark        | Change  |
-----------------+---------+
7zip             | +0.11%  |
Bullet           | +0.21%  |
ClamAV           | +0.08%  |
SPASS            | +0.25%  |
consumer-typeset | +0.14%  |
kimwitu++        | +0.35%  |
lencod           | +0.01%  |
mafft            | +0.01%  |
sqlite3          | +0.11%  |
tramp3d-v4       | +0.28%  |
-----------------+---------+
GEOMEAN          | 0.15%   |
```
(For reference, this is the change I tested https://github.com/llvm/llvm-project/pull/111672)

https://github.com/llvm/llvm-project/pull/111163