[PM] Fix instcombine's analysis preservation in the new pass manager to

cover domtree and alias analysis. These are the pretty clear analyses
that we would always want to survive this pass.

To make these survive, we also need to preserve the assumption cache.

Added a test that verifies the important bits of this preservation.

llvm-svn: 292037

1 files changed, 3 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
index 27fc34d2317..b2c4baae99b 100644
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -3178,7 +3178,10 @@ PreservedAnalyses InstCombinePass::run(Function &F,
   // Mark all the analyses that instcombine updates as preserved.
   // FIXME: This should also 'preserve the CFG'.
   PreservedAnalyses PA;
+  PA.preserve<AAManager>();
+  PA.preserve<AssumptionAnalysis>();
   PA.preserve<DominatorTreeAnalysis>();
+  PA.preserve<GlobalsAA>();
   return PA;
 }