Original Patch and summary by Philip Reames.
RewriteStatepointsForGC tries to rewrite a function in a manner where
the optimizer can't end up using a pointer value after it might have
been relocated by a safepoint. This pass checks the invariant that
RSForGC is supposed to establish and that (if we constructed semantics
correctly) later passes must preserve.
This has been a really useful diagnostic tool when initially developing
the rewriting scheme and has found numerous bugs.
Differential Revision: https://reviews.llvm.org/D15940
Reviewed by: swaroop.sridhar, mjacob
Subscribers: llvm-commits
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@307112 91177308-0d34-0410-b5e6-96231b3b80d8
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