Fix inline cost predictions with SCIENCE.

After running a batch of measurements, it is clear that the inliner metrics
need some adjustments:

Own argument bonus:       20 -> 5
Outgoing argument penalty: 0 -> 5
Alloca bonus:             10 -> 5
Constant instr bonus:      7 -> 5
Dead successor bonus:     40 -> 5*(avg instrs/block)

The new cost metrics are generaly 25 points higher than before, so we may need
to move thresholds.

With this change, InlineConstants::CallPenalty becomes a political correction:

if (!isa<IntrinsicInst>(II) && !callIsSmall(CS.getCalledFunction()))
  NumInsts += InlineConstants::CallPenalty + CS.arg_size();

The code size is accurately modelled by CS.arg_size(). CallPenalty is added
because calls tend to take a long time, so it may not be worth it to inline a
function with lots of calls.

All of the political corrections are in the InlineConstants namespace:
IndirectCallBonus, CallPenalty, LastCallToStaticBonus, ColdccPenalty,
NoreturnPenalty.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94615 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Analysis/InlineCost.h

@@ -64,7 +64,9 @@ namespace llvm {
 
   namespace InlineConstants {
     // Various magic constants used to adjust heuristics.
-    const int CallPenalty = 5;
+    const int InstrCost = 5;
+    const int IndirectCallBonus = 500;
+    const int CallPenalty = 5;  // In instrs, so multiply by InstrCost.
     const int LastCallToStaticBonus = -15000;
     const int ColdccPenalty = 2000;
     const int NoreturnPenalty = 10000;