[llvm] Reapply "[DFAJumpThreading] Enable DFAJumpThread by default." (PR #169183)

[Aiden Grossman via llvm-commits]

boomanaiden154 wrote:

https://gist.github.com/boomanaiden154/445779ab0e9bd122b9c8c15ce00db48f

Reproduces the issue:
```
aidengrossman at aidengrossman:/work/llvm-project/build$ ./bin/clang++ --target=x86_64 -Wno-override-module -O3 ./seed-renamed.ll -mllvm -enable-dfa-jump-thread=true -o /tmp/dfa_jump_thread
aidengrossman at aidengrossman:/work/llvm-project/build$ /tmp/dfa_jump_thread
aidengrossman at aidengrossman:/work/llvm-project/build$ echo $?
1
aidengrossman at aidengrossman:/work/llvm-project/build$ ./bin/clang++ --target=x86_64 -Wno-override-module -O3 ./seed-renamed.ll -mllvm -enable-dfa-jump-thread=false -o /tmp/normal
aidengrossman at aidengrossman:/work/llvm-project/build$ /tmp/normal
aidengrossman at aidengrossman:/work/llvm-project/build$ echo $?
0
aidengrossman at aidengrossman:/work/llvm-project/build$ git log --oneline --max-count=1
e71f243a8d0e (HEAD -> main, origin/main, origin/HEAD) [TableGen] Simplify MachineValueTypeSet::iterator::find_from_pos. NFC (#169227)
```

Sorry for the largeish reproducer. `llvm-reduce` kept reducing the test case in such a way that the interestingness test began to fail.

https://github.com/llvm/llvm-project/pull/169183