[llvm] [LICM] Use DomTreeUpdater version of SplitBlockPredecessors, nfc (PR #107190)

[Yingwei Zheng via llvm-commits]

dtcxzyw wrote:

I noticed that this patch caused a significant compilation time regression (~7%) when building php.
Reproducer: https://github.com/dtcxzyw/llvm-opt-benchmark/blob/main/bench/php/original/parse_date.ll
with commit 6f3c15163f9e: 
```
perf stat -e instructions:u bin/opt -O3 ../../llvm-opt-benchmark/bench/php/original/parse_date.ll --disable-output

Performance counter stats for 'bin/opt -O3 ../../llvm-opt-benchmark/bench/php/original/parse_date.ll --disable-output':

    16,235,016,831      instructions:u                                                        

       2.118263921 seconds time elapsed

       2.101738000 seconds user
       0.015998000 seconds sys
```
with this patch (commit 0bc98349c841):
```
perf stat -e instructions:u bin/opt -O3 ../../llvm-opt-benchmark/bench/php/original/parse_date.ll --disable-output

 Performance counter stats for 'bin/opt -O3 ../../llvm-opt-benchmark/bench/php/original/parse_date.ll --disable-output':

    44,855,633,670      instructions:u                                                        

       5.125998136 seconds time elapsed

       5.106567000 seconds user
       0.019002000 seconds sys
```

See https://github.com/dtcxzyw/llvm-opt-benchmark/issues/1399 for more details.
Can someone have a look?


https://github.com/llvm/llvm-project/pull/107190