Use cast<> instead of dyn_cast<> for things that are known to be
Instructions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73002 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/IPO/IPConstantPropagation.cpp b/lib/Transforms/IPO/IPConstantPropagation.cpp
index 2dc8558..e4a9dea 100644
--- a/lib/Transforms/IPO/IPConstantPropagation.cpp
+++ b/lib/Transforms/IPO/IPConstantPropagation.cpp
@@ -241,15 +241,11 @@
    
     for (Value::use_iterator I = Call->use_begin(), E = Call->use_end();
          I != E;) {
-      Instruction *Ins = dyn_cast<Instruction>(*I);
+      Instruction *Ins = cast<Instruction>(*I);
 
       // Increment now, so we can remove the use
       ++I;
 
-      // Not an instruction? Ignore
-      if (!Ins)
-        continue;
-
       // Find the index of the retval to replace with
       int index = -1;
       if (ExtractValueInst *EV = dyn_cast<ExtractValueInst>(Ins))