[flang-commits] [PATCH] D154374: [flang] Fix overflow detection for folding SUM/PRODUCT

[Peter Klausler via Phabricator via flang-commits]

klausler created this revision.
klausler added a reviewer: PeteSteinfeld.
klausler added a project: Flang.
Herald added subscribers: sunshaoce, jdoerfert.
Herald added a project: All.
klausler requested review of this revision.

The overflow detection code in the templates that fold SUM and PRODUCT
was checking for overflow before performing the reduction, not after.
Fix and add tests.


https://reviews.llvm.org/D154374

Files:
  flang/lib/Evaluate/fold-reduction.h
  flang/test/Evaluate/errors01.f90


Index: flang/test/Evaluate/errors01.f90
===================================================================
--- flang/test/Evaluate/errors01.f90
+++ flang/test/Evaluate/errors01.f90
@@ -163,6 +163,8 @@
     real, parameter :: bad3 = dim(huge(1.),-.5*huge(1.))
     !CHECK: warning: DIM intrinsic folding overflow
     integer, parameter :: bad4 = dim(huge(1),-1)
+    !CHECK: warning: HYPOT intrinsic folding overflow
+    real, parameter :: bad5 = hypot(huge(0.), huge(0.))
     !CHECK: warning: overflow on REAL(8) to REAL(4) conversion
     x = 1.D40
   end subroutine
Index: flang/lib/Evaluate/fold-reduction.h
===================================================================
--- flang/lib/Evaluate/fold-reduction.h
+++ flang/lib/Evaluate/fold-reduction.h
@@ -260,12 +260,12 @@
         element = prod.value;
       }
     }};
+    auto result{Expr<T>{DoReduction<T>(*array, dim, identity, accumulator)}};
     if (overflow) {
       context.messages().Say(
           "PRODUCT() of %s data overflowed"_warn_en_US, T::AsFortran());
-    } else {
-      return Expr<T>{DoReduction<T>(*array, dim, identity, accumulator)};
     }
+    return result;
   }
   return Expr<T>{std::move(ref)};
 }
@@ -301,12 +301,12 @@
         element = sum.value;
       }
     }};
+    auto result{Expr<T>{DoReduction<T>(*array, dim, identity, accumulator)}};
     if (overflow) {
       context.messages().Say(
           "SUM() of %s data overflowed"_warn_en_US, T::AsFortran());
-    } else {
-      return Expr<T>{DoReduction<T>(*array, dim, identity, accumulator)};
     }
+    return result;
   }
   return Expr<T>{std::move(ref)};
 }


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