[flang-commits] [flang] a68612a - [flang][runtime] Preserve effect of positioning in record in non-advancing output

[Peter Klausler via flang-commits]

Author: Peter Klausler
Date: 2022-04-14T15:33:15-07:00
New Revision: a68612a964b43d8382a93bb36084b51f2add756f

URL: https://github.com/llvm/llvm-project/commit/a68612a964b43d8382a93bb36084b51f2add756f
DIFF: https://github.com/llvm/llvm-project/commit/a68612a964b43d8382a93bb36084b51f2add756f.diff

LOG: [flang][runtime] Preserve effect of positioning in record in non-advancing output

When formatted non-advancing output ends in a control edit descriptor
like nX or Tn or TRn that effectively extends the record, fill any
gap with explicit blanks at the completion of the WRITE.

Differential Revision: https://reviews.llvm.org/D123716

Added: 
    

Modified: 
    flang/runtime/io-stmt.cpp

Removed: 
    


################################################################################
diff  --git a/flang/runtime/io-stmt.cpp b/flang/runtime/io-stmt.cpp
index fba77171062ef..ac2a7e0a11ed2 100644
--- a/flang/runtime/io-stmt.cpp
+++ b/flang/runtime/io-stmt.cpp
@@ -318,8 +318,13 @@ void ExternalIoStatementState<DIR>::CompleteOperation() {
     if (!mutableModes().nonAdvancing || GetIoStat() == IostatEor) {
       FinishReadingRecord();
     }
-  } else {
+  } else { // output
     if (mutableModes().nonAdvancing) {
+      // Make effects of positioning past the last Emit() visible with blanks.
+      std::int64_t n{unit().positionInRecord - unit().furthestPositionInRecord};
+      unit().positionInRecord = unit().furthestPositionInRecord;
+      while (n-- > 0 && unit().Emit(" ", 1, 1, *this)) {
+      }
       unit().leftTabLimit = unit().furthestPositionInRecord;
     } else {
       unit().leftTabLimit.reset();