fix PR6623: when optimizing for size, don't inline memcpy/memsets

that are too large.  This causes the freebsd bootloader to be too
large apparently.

It's unclear if this should be an -Os or -Oz thing.  Thoughts welcome.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105228 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 9 insertions, 0 deletions

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 86e00ce6e2..c1b5ec2538 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -3266,6 +3266,15 @@ static bool FindOptimalMemOpLowering(std::vector<EVT> &MemOps,
     if (VT.bitsGT(LVT))
       VT = LVT;
   }
+  
+  // If we're optimizing for size, and there is a limit, bump the maximum number
+  // of operations inserted down to 4.  This is a wild guess that approximates
+  // the size of a call to memcpy or memset (3 arguments + call).
+  if (Limit != ~0U) {
+    const Function *F = DAG.getMachineFunction().getFunction();
+    if (F->hasFnAttr(Attribute::OptimizeForSize))
+      Limit = 4;
+  }
 
   unsigned NumMemOps = 0;
   while (Size != 0) {