Chris Tate 588e16d8c7 Skip WebAssembly irreducible control flow analysis on reducible functions ...

LLVM's WebAssembly pass that gives multiple-entry loops a single entry
first records, for every block, every block it can reach. Its time and
memory grow with the square of a function's block count even when the
function has no such loop. In the three.js nodes fixture a module
initializer of 40,000 blocks spent four minutes and 22 GB in it, which
set the helper's peak and most of its wall time.

The helper now runs the pass only on functions whose control flow graph
is irreducible, and WebAssembly object emission leaves out the module
pass that collects external symbols for assembly declarations, so each
function's machine code is freed once it is printed. Optimized
partitions are compiled through the thin backend's pre-codegen hook to
use the same pipeline. Objects are unchanged.

2026-10-18 01:30:29 -05:00

..

llvm-codegen

Skip WebAssembly irreducible control flow analysis on reducible functions

2026-10-18 01:30:29 -05:00