Disable most IR-level transform passes on functions marked 'optnone'.

Ideally only those transform passes that run at -O0 remain enabled,
in reality we get as close as we reasonably can.
Passes are responsible for disabling themselves, it's not the job of
the pass manager to do it for them.

llvm-svn: 200892

1 files changed, 14 insertions, 0 deletions

diff --git a/llvm/lib/Analysis/LoopPass.cpp b/llvm/lib/Analysis/LoopPass.cpp
index 4775359c506..db69e1325a8 100644
--- a/llvm/lib/Analysis/LoopPass.cpp
+++ b/llvm/lib/Analysis/LoopPass.cpp
@@ -365,3 +365,17 @@ void LoopPass::assignPassManager(PMStack &PMS,
 
   LPPM->add(this);
 }
+
+// Containing function has Attribute::OptimizeNone and transformation
+// passes should skip it.
+bool LoopPass::skipOptnoneFunction(Loop *L) const {
+  Function *F = L->getHeader()->getParent();
+  if (F && F->hasFnAttribute(Attribute::OptimizeNone)) {
+    // FIXME: Report this to dbgs() only once per function.
+    DEBUG(dbgs() << "Skipping pass '" << getPassName()
+          << "' in function " << F->getName() << "\n");
+    // FIXME: Delete loop from pass manager's queue?
+    return true;
+  }
+  return false;
+}