[qt/clang/llvm]: Summary of bulk changes made

Git repository change summary for qt/clang/llvm
Pushed by mirror-service into branch 'upstream/users/madhur13490/lv-fp-argmin'.
Changed from 34bea2fbc00d44ff727e4cfd155b544a4a04c307 to 09f59794fb418d238b440a304cb2d983aefa9937
Acknowledgement was received that this change introduces only existing code that has been pushed to another public open source repository.

This change contains the following new commits:

Git commit 2aa7f969b1a37723730ec527dcbf8e74e86bfcc8 by Madhur Amilkanthwar on 10/08/2026 at 10:30..
[GVN] Recover affine-equal select-dependent load addresses

Teach PHITransAddr to recover available select-arm addresses when a
constant GEP index adjustment is folded into a nested byte offset. This
lets GVN reuse the existing load-PRE path without depending on SCEV.
https://invent.kde.org/qt/clang/llvm/-/commit/2aa7f969b1a37723730ec527dcbf8e74e86bfcc8

Git commit 09f59794fb418d238b440a304cb2d983aefa9937 by Madhur Amilkanthwar on 10/08/2026 at 10:30..
[LV] Vectorize down-counting floating-point argmin/argmax reductions

Extend the multi-use min/max reduction coupling so a floating-point
min/max value reduction can be paired with a down-counting (FindFirst)
index reduction, enabling argmin/argmax vectorization for loops whose
induction counts down.

Analysis (IVDescriptors):
 - Recognize select-based FP min/max recurrences, not just the
   intrinsic form.
 - For the shared-compare argmin/argmax shape (the reduction compare
   also feeds an index select), take the required NaN-free and
   signed-zero-free facts from the compare when the select itself does
   not carry them. Plain min/max reductions keep the strict
   flags-on-the-select rule.

VPlan (handleMultiUseReductions):
 - Accept a select as the value reduction's min/max operation and read
   its value operands accordingly.
 - Tolerate the shared compare feeding both the value select and the
   index select, skipping the value select when locating the index
   select.
 - Support the down-counting FindFirst index reduction (UMin/SMin) for
   floating-point, reconstructing the stored index from the base
   induction plus an additive offset (e.g. iv-1).
 - Fall back to scalar safely for shapes that are not handled.

Scope is intentionally limited to keep the change small:
 - TODO: floating-point up-counting (FindLast) argmin/argmax.
 - TODO: integer down-counting (FindFirst) argmin/argmax.

Add lit tests covering the down-counting floating-point argmin,
including the VF=1 scalar-plan path.
https://invent.kde.org/qt/clang/llvm/-/commit/09f59794fb418d238b440a304cb2d983aefa9937