[llvm-commits] [llvm] r156168 - in /llvm/trunk: include/llvm/Transforms/Utils/CodeExtractor.h lib/Transforms/Utils/CodeExtractor.cpp

[Chandler Carruth]

Author: chandlerc
Date: Fri May  4 06:20:27 2012
New Revision: 156168

URL: http://llvm.org/viewvc/llvm-project?rev=156168&view=rev
Log:
Factor the computation of input and output sets into a public interface
of the CodeExtractor utility. This allows speculatively computing input
and output sets to measure the likely size impact of the code
extraction.

These sets cannot be reused sadly -- we mutate the function prior to
forming the final sets used by the actual extraction.

The interface has been revamped slightly to make it easier to use
correctly by making the interface const and sinking the computation of
the number of exit blocks into the full extraction function and away
from the rest of this logic which just computed two output parameters.

Modified:
    llvm/trunk/include/llvm/Transforms/Utils/CodeExtractor.h
    llvm/trunk/lib/Transforms/Utils/CodeExtractor.cpp

Modified: llvm/trunk/include/llvm/Transforms/Utils/CodeExtractor.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Transforms/Utils/CodeExtractor.h?rev=156168&r1=156167&r2=156168&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Transforms/Utils/CodeExtractor.h (original)
+++ llvm/trunk/include/llvm/Transforms/Utils/CodeExtractor.h Fri May  4 06:20:27 2012
@@ -84,12 +84,21 @@
     ///
     /// Based on the blocks used when constructing the code extractor,
     /// determine whether it is eligible for extraction.
-    bool isEligible() { return !Blocks.empty(); };
+    bool isEligible() const { return !Blocks.empty(); };
+
+    /// \brief Compute the set of input values and output values for the code.
+    ///
+    /// These can be used either when performing the extraction or to evaluate
+    /// the expected size of a call to the extracted function. Note that this
+    /// work cannot be cached between the two as once we decide to extract
+    /// a code sequence, that sequence is modified, including changing these
+    /// sets, before extraction occurs. These modifications won't have any
+    /// significant impact on the cost however.
+    void findInputsOutputs(ValueSet &Inputs, ValueSet &Outputs) const;
 
   private:
     void severSplitPHINodes(BasicBlock *&Header);
     void splitReturnBlocks();
-    void findInputsOutputs(ValueSet &inputs, ValueSet &outputs);
 
     Function *constructFunction(const ValueSet &inputs,
                                 const ValueSet &outputs,

Modified: llvm/trunk/lib/Transforms/Utils/CodeExtractor.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/CodeExtractor.cpp?rev=156168&r1=156167&r2=156168&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/CodeExtractor.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/CodeExtractor.cpp Fri May  4 06:20:27 2012
@@ -109,7 +109,6 @@
   : DT(&DT), AggregateArgs(AggregateArgs||AggregateArgsOpt),
     Blocks(buildExtractionBlockSet(L.getBlocks())), NumExitBlocks(~0U) {}
 
-
 /// definedInRegion - Return true if the specified value is defined in the
 /// extracted region.
 static bool definedInRegion(const SetVector<BasicBlock *> &Blocks, Value *V) {
@@ -130,6 +129,32 @@
   return false;
 }
 
+void CodeExtractor::findInputsOutputs(ValueSet &Inputs,
+                                      ValueSet &Outputs) const {
+  for (SetVector<BasicBlock *>::const_iterator I = Blocks.begin(),
+                                               E = Blocks.end();
+       I != E; ++I) {
+    BasicBlock *BB = *I;
+
+    // If a used value is defined outside the region, it's an input.  If an
+    // instruction is used outside the region, it's an output.
+    for (BasicBlock::iterator II = BB->begin(), IE = BB->end();
+         II != IE; ++II) {
+      for (User::op_iterator OI = II->op_begin(), OE = II->op_end();
+           OI != OE; ++OI)
+        if (definedInCaller(Blocks, *OI))
+          Inputs.insert(*OI);
+
+      for (Value::use_iterator UI = II->use_begin(), UE = II->use_end();
+           UI != UE; ++UI)
+        if (!definedInRegion(Blocks, *UI)) {
+          Outputs.insert(II);
+          break;
+        }
+    }
+  }
+}
+
 /// severSplitPHINodes - If a PHI node has multiple inputs from outside of the
 /// region, we need to split the entry block of the region so that the PHI node
 /// is easier to deal with.
@@ -233,40 +258,6 @@
     }
 }
 
-// findInputsOutputs - Find inputs to, outputs from the code region.
-//
-void CodeExtractor::findInputsOutputs(ValueSet &inputs, ValueSet &outputs) {
-  std::set<BasicBlock*> ExitBlocks;
-  for (SetVector<BasicBlock*>::const_iterator ci = Blocks.begin(),
-       ce = Blocks.end(); ci != ce; ++ci) {
-    BasicBlock *BB = *ci;
-
-    for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
-      // If a used value is defined outside the region, it's an input.  If an
-      // instruction is used outside the region, it's an output.
-      for (User::op_iterator O = I->op_begin(), E = I->op_end(); O != E; ++O)
-        if (definedInCaller(Blocks, *O))
-          inputs.insert(*O);
-
-      // Consider uses of this instruction (outputs).
-      for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
-           UI != E; ++UI)
-        if (!definedInRegion(Blocks, *UI)) {
-          outputs.insert(I);
-          break;
-        }
-    } // for: insts
-
-    // Keep track of the exit blocks from the region.
-    TerminatorInst *TI = BB->getTerminator();
-    for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
-      if (!Blocks.count(TI->getSuccessor(i)))
-        ExitBlocks.insert(TI->getSuccessor(i));
-  } // for: basic blocks
-
-  NumExitBlocks = ExitBlocks.size();
-}
-
 /// constructFunction - make a function based on inputs and outputs, as follows:
 /// f(in0, ..., inN, out0, ..., outN)
 ///
@@ -701,6 +692,14 @@
   // Find inputs to, outputs from the code region.
   findInputsOutputs(inputs, outputs);
 
+  SmallPtrSet<BasicBlock *, 1> ExitBlocks;
+  for (SetVector<BasicBlock *>::iterator I = Blocks.begin(), E = Blocks.end();
+       I != E; ++I)
+    for (succ_iterator SI = succ_begin(*I), SE = succ_end(*I); SI != SE; ++SI)
+      if (!Blocks.count(*SI))
+        ExitBlocks.insert(*SI);
+  NumExitBlocks = ExitBlocks.size();
+
   // Construct new function based on inputs/outputs & add allocas for all defs.
   Function *newFunction = constructFunction(inputs, outputs, header,
                                             newFuncRoot,