[flang] fix bug noticed by Jean

Original-commit: flang-compiler/f18@9acbff7585fbc113391066e5e79c1059c0e22d54
Reviewed-on: https://github.com/flang-compiler/f18/pull/244

diff --git a/flang/lib/evaluate/integer.h b/flang/lib/evaluate/integer.h
index 0c97be3..75d41e4 100644 (file)
--- a/flang/lib/evaluate/integer.h
+++ b/flang/lib/evaluate/integer.h
@@ -160,15 +160,15 @@ public:
         }
       } else {
         INT signExtension{-(n < 0)};
+        static_assert(nBits >= partBits);
         if constexpr (nBits > partBits) {
-          signExtension <<= partBits;
+          signExtension <<= nBits - partBits;
           for (int j{0}; j < parts; ++j) {
             SetLEPart(j, static_cast<Part>(n));
             n >>= partBits;
             n |= signExtension;
           }
         } else {
-          static_assert(nBits == partBits);
           SetLEPart(0, static_cast<Part>(n));
           for (int j{1}; j < parts; ++j) {
             SetLEPart(j, static_cast<Part>(signExtension));