IR: RF_IgnoreMissingValues => RF_IgnoreMissingLocals, NFC

Clarify what this RemapFlag actually means.

  - Change the flag name to match its intended behaviour.
  - Clearly document that it's not supposed to affect globals.
  - Add a host of FIXMEs to indicate how to fix the behaviour to match
    the intent of the flag.

RF_IgnoreMissingLocals should only affect the behaviour of
RemapInstruction for function-local operands; namely, for operands of
type Argument, Instruction, and BasicBlock.  Currently, it is *only*
passed into RemapInstruction calls (and the transitive MapValue calls
that it makes).

When I split Metadata from Value I didn't understand the flag, and I
used it in a bunch of places for "global" metadata.

This commit doesn't have any functionality change, but prepares to
cleanup MapMetadata and MapValue.

llvm-svn: 265628

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/Utils/CloneFunction.cpp b/llvm/lib/Transforms/Utils/CloneFunction.cpp
index 8e1715a..cf39ae9 100644
--- a/llvm/lib/Transforms/Utils/CloneFunction.cpp
+++ b/llvm/lib/Transforms/Utils/CloneFunction.cpp
@@ -694,7 +694,7 @@ void llvm::remapInstructionsInBlocks(
   for (auto *BB : Blocks)
     for (auto &Inst : *BB)
       RemapInstruction(&Inst, VMap,
-                       RF_NoModuleLevelChanges | RF_IgnoreMissingEntries);
+                       RF_NoModuleLevelChanges | RF_IgnoreMissingLocals);
 }
 
 /// \brief Clones a loop \p OrigLoop.  Returns the loop and the blocks in \p