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/Scalar/LoopUnswitch.cpp b/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp
index c3b941f46f6..955604f0507 100644
--- a/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp
@@ -1068,7 +1068,7 @@ void LoopUnswitch::UnswitchNontrivialCondition(Value *LIC, Constant *Val,
     for (BasicBlock::iterator I = NewBlocks[i]->begin(),
            E = NewBlocks[i]->end(); I != E; ++I)
       RemapInstruction(&*I, VMap,
-                       RF_NoModuleLevelChanges | RF_IgnoreMissingEntries);
+                       RF_NoModuleLevelChanges | RF_IgnoreMissingLocals);
 
   // Rewrite the original preheader to select between versions of the loop.
   BranchInst *OldBR = cast<BranchInst>(loopPreheader->getTerminator());