tree-optimization/106722 - uninit analysis with long def -> use path
The following applies similar measures as r13-2133-ge66cf626c72d58
to the computation of the use predicate when the path from PHI def
to use is too long and we run into compute_control_dep_chain limits.
It also moves the preprocessor define limits internal.
This resolves the reduced testcase but not the original one.
PR tree-optimization/106722
* gimple-predicate-analysis.h (MAX_NUM_CHAINS, MAX_CHAIN_LEN,
MAX_POSTDOM_CHECK, MAX_SWITCH_CASES): Move ...
* gimple-predicate-analysis.cc: ... here and document.
(simple_control_dep_chain): New function, factored from
predicate::use_cannot_happen.
(predicate::use_cannot_happen): Adjust.
(predicate::predicate): Use simple_control_dep_chain as fallback.
* g++.dg/uninit-pr106722-1.C: New testcase.