Begin fleshing out an interface in TTI for modelling the costs of

generic function calls and intrinsics. This is somewhat overlapping with
an existing intrinsic cost method, but that one seems targetted at
vector intrinsics. I'll merge them or separate their names and use cases
in a separate commit.

This sinks the test of 'callIsSmall' down into TTI where targets can
control it. The whole thing feels very hack-ish to me though. I've left
a FIXME comment about the fundamental design problem this presents. It
isn't yet clear to me what the users of this function *really* care
about. I'll have to do more analysis to figure that out. Putting this
here at least provides it access to proper analysis pass tools and other
such. It also allows us to more cleanly implement the baseline cost
interfaces in TTI.

With this commit, it is now theoretically possible to simplify much of
the inline cost analysis's handling of calls by calling through to this
interface. That conversion will have to happen in subsequent commits as
it requires more extensive restructuring of the inline cost analysis.

The CodeMetrics class is now really only in the business of running over
a block of code and aggregating the metrics on that block of code, with
the actual cost evaluation done entirely in terms of TTI.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173148 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 4 insertions, 44 deletions

diff --git a/lib/Analysis/CodeMetrics.cpp b/lib/Analysis/CodeMetrics.cpp
index 073234bf7c..8cda01a24c 100644
--- a/lib/Analysis/CodeMetrics.cpp
+++ b/lib/Analysis/CodeMetrics.cpp
@@ -20,41 +20,6 @@
 
 using namespace llvm;
 
-/// callIsSmall - If a call is likely to lower to a single target instruction,
-/// or is otherwise deemed small return true.
-/// TODO: Perhaps calls like memcpy, strcpy, etc?
-bool llvm::callIsSmall(ImmutableCallSite CS) {
-  if (isa<IntrinsicInst>(CS.getInstruction()))
-    return true;
-
-  const Function *F = CS.getCalledFunction();
-  if (!F) return false;
-
-  if (F->hasLocalLinkage()) return false;
-
-  if (!F->hasName()) return false;
-
-  StringRef Name = F->getName();
-
-  // These will all likely lower to a single selection DAG node.
-  if (Name == "copysign" || Name == "copysignf" || Name == "copysignl" ||
-      Name == "fabs" || Name == "fabsf" || Name == "fabsl" ||
-      Name == "sin" || Name == "sinf" || Name == "sinl" ||
-      Name == "cos" || Name == "cosf" || Name == "cosl" ||
-      Name == "sqrt" || Name == "sqrtf" || Name == "sqrtl" )
-    return true;
-
-  // These are all likely to be optimized into something smaller.
-  if (Name == "pow" || Name == "powf" || Name == "powl" ||
-      Name == "exp2" || Name == "exp2l" || Name == "exp2f" ||
-      Name == "floor" || Name == "floorf" || Name == "ceil" ||
-      Name == "round" || Name == "ffs" || Name == "ffsl" ||
-      Name == "abs" || Name == "labs" || Name == "llabs")
-    return true;
-
-  return false;
-}
-
 /// analyzeBasicBlock - Fill in the current structure with information gleaned
 /// from the specified block.
 void CodeMetrics::analyzeBasicBlock(const BasicBlock *BB,
@@ -63,9 +28,6 @@ void CodeMetrics::analyzeBasicBlock(const BasicBlock *BB,
   unsigned NumInstsBeforeThisBB = NumInsts;
   for (BasicBlock::const_iterator II = BB->begin(), E = BB->end();
        II != E; ++II) {
-    if (TargetTransformInfo::TCC_Free == TTI.getUserCost(&*II))
-      continue;
-
     // Special handling for calls.
     if (isa<CallInst>(II) || isa<InvokeInst>(II)) {
       ImmutableCallSite CS(cast<Instruction>(II));
@@ -83,12 +45,10 @@ void CodeMetrics::analyzeBasicBlock(const BasicBlock *BB,
         // for that case.
         if (F == BB->getParent())
           isRecursive = true;
-      }
-
-      if (!callIsSmall(CS)) {
-        // Each argument to a call takes on average one instruction to set up.
-        NumInsts += CS.arg_size();
 
+        if (TTI.isLoweredToCall(F))
+          ++NumCalls;
+      } else {
         // We don't want inline asm to count as a call - that would prevent loop
         // unrolling. The argument setup cost is still real, though.
         if (!isa<InlineAsm>(CS.getCalledValue()))
@@ -112,7 +72,7 @@ void CodeMetrics::analyzeBasicBlock(const BasicBlock *BB,
       if (InvI->hasFnAttr(Attribute::NoDuplicate))
         notDuplicatable = true;
 
-    ++NumInsts;
+    NumInsts += TTI.getUserCost(&*II);
   }
 
   if (isa<ReturnInst>(BB->getTerminator()))