tree e28bdef22fad7210f851410c122678a1beed9a90
parent 076166ab4e13506c90448b5d6e0f34c3939ee76f
author Than McIntosh <thanm@google.com> 1712848582 +0000
committer Than McIntosh <thanm@google.com> 1713382759 +0000

cmd/compile/internal/ssa: delay rewrite cycle detection for huge funcs

The SSA rewrite pass has some logic that looks to see whether a
suspiciously large number of rewrites is happening, and if so, turns
on logic to try to detect rewrite cycles. The cycle detection logic is
quite expensive (hashes the entire function), meaning that for very
large functions we might get a successful compilation in a minute or
two with no cycle detection, but take a couple of hours once cycle
detection kicks in.

This patch moves from a fixed limit of 1000 iterations to a limit set
partially based on the size of the function (meaning that we'll wait
longer before turning cycle detection for a large func).

Fixes #66773.

Change-Id: I72f8524d706f15b3f0150baf6abeab2a5d3e15c4
Reviewed-on: https://go-review.googlesource.com/c/go/+/578215
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>