do not bother inlining nullary functions without return values. The only

effect these calls can have is due to global variables, and these passes
all use the globals graph to capture their effect anyway.  This speeds up
the BU pass very slightly on perlbmk, reducing the number of dsnodes
allocated from 98913 to 96423.

llvm-svn: 20676

1 files changed, 5 insertions, 1 deletions

diff --git a/llvm/lib/Analysis/DataStructure/CompleteBottomUp.cpp b/llvm/lib/Analysis/DataStructure/CompleteBottomUp.cpp
index 5a0436c0616..a70080a8c66 100644
--- a/llvm/lib/Analysis/DataStructure/CompleteBottomUp.cpp
+++ b/llvm/lib/Analysis/DataStructure/CompleteBottomUp.cpp
@@ -217,7 +217,11 @@ void CompleteBUDataStructures::processGraph(DSGraph &G) {
 
     assert(calls.insert(TheCall).second &&
            "Call instruction occurs multiple times in graph??");
-      
+    
+    // Fast path for noop calls.  Note that we don't care about merging globals
+    // in the callee with nodes in the caller here.
+    if (CS.getRetVal().isNull() && CS.getNumPtrArgs() == 0)
+      continue;
 
     // Loop over all of the potentially called functions...
     // Inline direct calls as well as indirect calls because the direct