Chris Tate 0933548b8d Simplify optimized partitions at O1 before the thin link ...

An optimized program divided into partitions was simplified at O2 before
the thin link and optimized again at O2 after importing, so the work on
each partition's largest functions ran twice. The pre-link now runs the
O1 simplification, which still annotates the profile and inlines and
simplifies enough for the summaries the import decisions read; the
backend's O2 optimization is unchanged. A program optimized as one module
is unchanged.

The O1 simplification has no correlated value propagation. Without it,
SimplifyCFG folds a jammed loop's early exit and its trip-count exit into
one branch, the loop's latch no longer exits, and the backend's unroller
keeps a trip-count test in every unrolled iteration. The pre-link runs the
pass once per function after simplifying it.

2026-10-30 00:51:09 -05:00

..

llvm-codegen

Simplify optimized partitions at O1 before the thin link

2026-10-30 00:51:09 -05:00