Integrate llvm/llvm-project@3446ff1

[IanWood1]

Reverts:

• Carries local revert of Reland "Redesign Straight-Line Strength Reduction (SLSR) (#162930)" llvm/llvm-project#169614 due to resnet50-v2-7 test is flaky on gfx1100 #22649.
• Adds revert of [mlir][Linalg] implement bufferization for linalg.pack llvm/llvm-project#177982. reifyResultShapes() is unimplemented for pack ops on memrefs causing a crash in getPackUnPackIterationDomain

Fixes:

• Passes LLVM::DIFlags::Zero to address the added argument for LLVM::DIDerivedTypeAttr::get() llvm/llvm-project#177889
• Removes he firstIndex parameter to address the API change to visitNonControlFlowArguments() llvm/llvm-project#175210

https://github.com/iree-org/llvm-project/tree/sm-iree-integrates/llvm-20260128