[IR] Add fast-math support to {u,s}itofp (#198470)
- `{u,s}itofp` are floating point typed values.
- CodeGen part (foldFPToIntToFP in DAGCombiner) needs `nsz` to fold
pattern (uitofp (fptoui x)) -> (trunc x).
- LLVM has intrinsic variants of `{u,s}itofp`, which already support
fast-math flags.
Now optimization flags require 9 bits in bitcode, fast-math flags of
`uitofp` are stored in high 8 bits.
VPlan part may need some extra work, it assumes optimization flags from
different categories are disjoint.
[LoopFusion] Reform LCSSA after peelFusionCandidate's peelLoop (#200442)
peelLoop's internal simplifyLoop call requires LCSSA to be preserved
across it, but the cloned exit edges and cloned defs that peelLoop
introduces are not reflected in the existing LCSSA phis, so the contract
cannot be honoured. Pass PreserveLCSSA=false to peelLoop here and reform
LCSSA on the affected nest immediately afterward. LCSSA is expected
before and after peel+fuse, just not during it.
Caught by yarpgen fuzzing of clang -O3 -fexperimental-loop-fusion -mllvm
-loop-fusion-peel-max-count=8 on AArch64.
Fixes #199418
[libc++] Simplify unique_ptr constructor SFINAE (#201305)
This patch does a couple of things:
- inline aliases to `__enable_if_t`s, making it easier to understand
what's actually going on
- make the `enable_if`s dependent via a `class _Deleter = deleter_type`
instead of a `bool` and `__dependent_type`, reducing the number of
instantiated classes
- remove `__unique_ptr_deleter_sfinae`
