[tablegen] Delete duplicates from a vector without skipping elements

Tablegen's -gen-instr-info pass has a bug in its emitEnums() routine.
The function intends for values in a vector to be deduplicated, but it
accidentally skips over elements after performing a deletion.

I think there are smarter ways of doing this deduplication, but we can
do that in a follow-up commit if there's interest. See the thread:
[PATCH] TableGen InstrMapping Bug fix.

Patch by Tyler Kenney!

llvm-svn: 288408

1 files changed, 1 insertions, 0 deletions

diff --git a/llvm/utils/TableGen/CodeGenMapTable.cpp b/llvm/utils/TableGen/CodeGenMapTable.cpp
index 527f530da47..8032d7b3ee9 100644
--- a/llvm/utils/TableGen/CodeGenMapTable.cpp
+++ b/llvm/utils/TableGen/CodeGenMapTable.cpp
@@ -542,6 +542,7 @@ static void emitEnums(raw_ostream &OS, RecordKeeper &Records) {
       for (unsigned j = i+1; j < FieldValues.size(); j++) {
         if (CurVal == FieldValues[j]) {
           FieldValues.erase(FieldValues.begin()+j);
+          --j;
         }
       }
     }