[llvm-commits] CVS: llvm/lib/Transforms/Utils/Local.cpp

[Chris Lattner]

Changes in directory llvm/lib/Transforms/Utils:

Local.cpp updated: 1.18 -> 1.19

---
Log message:

Add a simple call constant propagation interface.


---
Diffs of the changes:  (+51 -0)

Index: llvm/lib/Transforms/Utils/Local.cpp
diff -u llvm/lib/Transforms/Utils/Local.cpp:1.18 llvm/lib/Transforms/Utils/Local.cpp:1.19
--- llvm/lib/Transforms/Utils/Local.cpp:1.18	Thu Mar 11 23:53:03 2004
+++ llvm/lib/Transforms/Utils/Local.cpp	Tue Apr 13 14:28:52 2004
@@ -57,6 +57,18 @@
     
     // If we reach here, all incoming values are the same constant.
     return Result;
+  } else if (CallInst *CI = dyn_cast<CallInst>(I)) {
+    if (Function *F = CI->getCalledFunction())
+      if (canConstantFoldCallTo(F)) {
+        std::vector<Constant*> Args;
+        for (unsigned i = 1, e = CI->getNumOperands(); i != e; ++i)
+          if (Constant *Op = dyn_cast<Constant>(CI->getOperand(i)))
+            Args.push_back(Op);
+          else
+            return 0;
+        return ConstantFoldCall(F, Args);
+      }
+    return 0;
   }
 
   Constant *Op0 = 0, *Op1 = 0;
@@ -215,6 +227,45 @@
   }
   return false;
 }
+
+/// canConstantFoldCallTo - Return true if its even possible to fold a call to
+/// the specified function.
+bool llvm::canConstantFoldCallTo(Function *F) {
+  const std::string &Name = F->getName();
+  return Name == "sin" || Name == "cos" || Name == "tan" || Name == "sqrt";
+}
+
+/// ConstantFoldCall - Attempt to constant fold a call to the specified function
+/// with the specified arguments, returning null if unsuccessful.
+Constant *llvm::ConstantFoldCall(Function *F,
+                                 const std::vector<Constant*> &Operands) {
+  const std::string &Name = F->getName();
+  const Type *Ty = F->getReturnType();
+
+  if (Name == "sin") {
+    if (Operands.size() == 1)
+      if (ConstantFP *CFP = dyn_cast<ConstantFP>(Operands[0]))
+        return ConstantFP::get(Ty, sin(CFP->getValue()));
+    
+  } else if (Name == "cos") {
+    if (Operands.size() == 1)
+      if (ConstantFP *CFP = dyn_cast<ConstantFP>(Operands[0]))
+        return ConstantFP::get(Ty, cos(CFP->getValue()));
+
+  } else if (Name == "tan") {
+    if (Operands.size() == 1)
+      if (ConstantFP *CFP = dyn_cast<ConstantFP>(Operands[0]))
+        return ConstantFP::get(Ty, tan(CFP->getValue()));
+
+  } else if (Name == "sqrt") {
+    if (Operands.size() == 1)
+      if (ConstantFP *CFP = dyn_cast<ConstantFP>(Operands[0]))
+        if (CFP->getValue() >= 0)
+          return ConstantFP::get(Ty, sqrt(CFP->getValue()));
+  }
+  return 0;
+}
+