[flang-commits] [PATCH] D129021: [flang][runtime] Fix directed UP/DOWN rounding edge case for Fw.d output

[Peter Klausler via Phabricator via flang-commits]

klausler created this revision.
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When Fw.d output editing takes place with directed rounding, make sure that
nonzero values that would normally be converted to zero round up (or down,
depending on the sign) to a scaled 1.


https://reviews.llvm.org/D129021

Files:
  flang/runtime/edit-output.cpp


Index: flang/runtime/edit-output.cpp
===================================================================
--- flang/runtime/edit-output.cpp
+++ flang/runtime/edit-output.cpp
@@ -419,15 +419,22 @@
       canIncrease = false; // only once
       continue;
     } else if (expo == -fracDigits && convertedDigits > 0) {
-      if (rounding != decimal::FortranRounding::RoundToZero) {
-        // Convert again without rounding so that we can round here
-        rounding = decimal::FortranRounding::RoundToZero;
-        continue;
-      } else if (converted.str[signLength] >= '5') {
-        // Value rounds up to a scaled 1 (e.g., 0.06 for F5.1 -> 0.1)
+      if ((rounding == decimal::FortranRounding::RoundUp &&
+              *converted.str != '-') ||
+          (rounding == decimal::FortranRounding::RoundDown &&
+              *converted.str == '-') ||
+          (rounding == decimal::FortranRounding::RoundToZero &&
+              rounding != edit.modes.round && // it changed below
+              converted.str[signLength] >= '5')) {
+        // Round up/down to a scaled 1
         ++expo;
         convertedDigits = 0;
         trailingOnes = 1;
+      } else if (rounding != decimal::FortranRounding::RoundToZero) {
+        // Convert again with truncation so first digit can be checked
+        // on the next iteration by the code above
+        rounding = decimal::FortranRounding::RoundToZero;
+        continue;
       } else {
         // Value rounds down to zero
         expo = 0;


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