X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Fllvm%2FAnalysis%2FInstructionSimplify.h;h=d760a4cba1cfbafa8bed4a3fc89f43d77556ff82;hb=326ae27c4f744cc7fb43f5a413d042d54fc1ddc0;hp=dd643a0469387c603da5d93783071dd2d9355017;hpb=c98bd9f1a79adffe73acd337b6f7f9afa6bae078;p=oota-llvm.git

diff --git a/include/llvm/Analysis/InstructionSimplify.h b/include/llvm/Analysis/InstructionSimplify.h
index dd643a04693..d760a4cba1c 100644
--- a/include/llvm/Analysis/InstructionSimplify.h
+++ b/include/llvm/Analysis/InstructionSimplify.h
@@ -14,12 +14,25 @@
 // ("and i32 %x, %x" -> "%x").  If the simplification is also an instruction
 // then it dominates the original instruction.
 //
+// These routines implicitly resolve undef uses. The easiest way to be safe when
+// using these routines to obtain simplified values for existing instructions is
+// to always replace all uses of the instructions with the resulting simplified
+// values. This will prevent other code from seeing the same undef uses and
+// resolving them to different values.
+//
+// These routines are designed to tolerate moderately incomplete IR, such as
+// instructions that are not connected to basic blocks yet. However, they do
+// require that all the IR that they encounter be valid. In particular, they
+// require that all non-constant values be defined in the same function, and the
+// same call context of that function (and not split between caller and callee
+// contexts of a directly recursive call, for example).
+//
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_ANALYSIS_INSTRUCTIONSIMPLIFY_H
 #define LLVM_ANALYSIS_INSTRUCTIONSIMPLIFY_H
 
-#include "llvm/User.h"
+#include "llvm/IR/User.h"
 
 namespace llvm {
   template<typename T>
@@ -211,7 +224,7 @@ namespace llvm {
   /// the result.
   ///
   /// If this call could not be simplified returns null.
-  Value *SimplifyCall(Value *F, User::op_iterator ArgBegin,
+  Value *SimplifyCall(Value *V, User::op_iterator ArgBegin,
                       User::op_iterator ArgEnd, const DataLayout *TD = 0,
                       const TargetLibraryInfo *TLI = 0,
                       const DominatorTree *DT = 0);
@@ -220,7 +233,7 @@ namespace llvm {
   /// result.
   ///
   /// If this call could not be simplified returns null.
-  Value *SimplifyCall(Value *F, ArrayRef<Value *> Args,
+  Value *SimplifyCall(Value *V, ArrayRef<Value *> Args,
                       const DataLayout *TD = 0,
                       const TargetLibraryInfo *TLI = 0,
                       const DominatorTree *DT = 0);