[PM] Introduce an analysis set used to preserve all analyses over

a function's CFG when that CFG is unchanged.

This allows transformation passes to simply claim they preserve the CFG
and analysis passes to check for the CFG being preserved to remove the
fanout of all analyses being listed in all passes.

I've gone through and removed or cleaned up as many of the comments
reminding us to do this as I could.

Differential Revision: https://reviews.llvm.org/D28627

llvm-svn: 292054

1 files changed, 9 insertions, 0 deletions

diff --git a/llvm/lib/Analysis/BlockFrequencyInfo.cpp b/llvm/lib/Analysis/BlockFrequencyInfo.cpp
index 4cdbe4d0fcf..9c1c9667a67 100644
--- a/llvm/lib/Analysis/BlockFrequencyInfo.cpp
+++ b/llvm/lib/Analysis/BlockFrequencyInfo.cpp
@@ -132,6 +132,15 @@ BlockFrequencyInfo &BlockFrequencyInfo::operator=(BlockFrequencyInfo &&RHS) {
 // template instantiated which is not available in the header.
 BlockFrequencyInfo::~BlockFrequencyInfo() {}
 
+bool BlockFrequencyInfo::invalidate(Function &F, const PreservedAnalyses &PA,
+                                    FunctionAnalysisManager::Invalidator &) {
+  // Check whether the analysis, all analyses on functions, or the function's
+  // CFG have been preserved.
+  auto PAC = PA.getChecker<BlockFrequencyAnalysis>();
+  return !(PAC.preserved() || PAC.preservedSet<AllAnalysesOn<Function>>() ||
+           PAC.preservedSet<CFGAnalyses>());
+}
+
 void BlockFrequencyInfo::calculate(const Function &F,
                                    const BranchProbabilityInfo &BPI,
                                    const LoopInfo &LI) {