[flang] Fold SPACING() correctly when result is subnormal

The intrinsic function SPACING() was being folded to the smallest
normal number (TINY(x)) rather than to a smaller subnormal result
when that result really was subnormal.

Differential Revision: https://reviews.llvm.org/D132155

diff --git a/flang/lib/Evaluate/real.cpp b/flang/lib/Evaluate/real.cpp
index 0af0ef2..ca0f4fd 100644 (file)
--- a/flang/lib/Evaluate/real.cpp
+++ b/flang/lib/Evaluate/real.cpp
@@ -749,8 +749,7 @@ template <typename W, int P> Real<W, P> Real<W, P>::SPACING() const {
     return TINY();
   } else {
     Real result;
-    result.Normalize(
-        false, Exponent() - binaryPrecision + 1, Fraction::MASKL(1));
+    result.Normalize(false, Exponent(), Fraction::MASKR(1));
     return result;
   }
 }

diff --git a/flang/test/Evaluate/fold-spacing.f90 b/flang/test/Evaluate/fold-spacing.f90
index d802f17..27834da 100644 (file)
--- a/flang/test/Evaluate/fold-spacing.f90
+++ b/flang/test/Evaluate/fold-spacing.f90
@@ -5,6 +5,8 @@ module m
   logical, parameter :: test_2 = spacing(-3.0) == scale(1.0, -22)
   logical, parameter :: test_3 = spacing(3.0d0) == scale(1.0, -51)
   logical, parameter :: test_4 = spacing(0.) == tiny(0.)
+  logical, parameter :: test_5 = spacing(tiny(0.)) == 1.e-45
+  logical, parameter :: test_6 = spacing(8388608.) == 1.
   logical, parameter :: test_11 = rrspacing(3.0) == scale(0.75, 24)
   logical, parameter :: test_12 = rrspacing(-3.0) == scale(0.75, 24)
   logical, parameter :: test_13 = rrspacing(3.0d0) == scale(0.75, 53)