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, 2 insertions, 2 deletions

diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
index f750509a5e8..8284d6bf626 100644
--- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -2236,7 +2236,7 @@ bool llvm::FoldBranchToCommonDest(BranchInst *BI, unsigned BonusInstThreshold) {
         continue;
       Instruction *NewBonusInst = BonusInst->clone();
       RemapInstruction(NewBonusInst, VMap,
-                       RF_NoModuleLevelChanges | RF_IgnoreMissingEntries);
+                       RF_NoModuleLevelChanges | RF_IgnoreMissingLocals);
       VMap[&*BonusInst] = NewBonusInst;
 
       // If we moved a load, we cannot any longer claim any knowledge about
@@ -2255,7 +2255,7 @@ bool llvm::FoldBranchToCommonDest(BranchInst *BI, unsigned BonusInstThreshold) {
     // two conditions together.
     Instruction *New = Cond->clone();
     RemapInstruction(New, VMap,
-                     RF_NoModuleLevelChanges | RF_IgnoreMissingEntries);
+                     RF_NoModuleLevelChanges | RF_IgnoreMissingLocals);
     PredBlock->getInstList().insert(PBI->getIterator(), New);
     New->takeName(Cond);
     Cond->setName(New->getName() + ".old");