[flang-commits] [flang] b2b4379 - [flang] Warn about overflow after folding HYPOT

[Peter Klausler via flang-commits]

Author: Peter Klausler
Date: 2023-07-03T11:21:32-07:00
New Revision: b2b43794b977d0a4b11bddb9fee4f04cbddce25d

URL: https://github.com/llvm/llvm-project/commit/b2b43794b977d0a4b11bddb9fee4f04cbddce25d
DIFF: https://github.com/llvm/llvm-project/commit/b2b43794b977d0a4b11bddb9fee4f04cbddce25d.diff

LOG: [flang] Warn about overflow after folding HYPOT

The code that folds the intrinsic function HYPOT was neglecting to
warn the programmer about overflow when it occurs.

Differential Revision: https://reviews.llvm.org/D154371

Added: 
    

Modified: 
    flang/lib/Evaluate/fold-real.cpp
    flang/test/Evaluate/errors01.f90

Removed: 
    


################################################################################
diff  --git a/flang/lib/Evaluate/fold-real.cpp b/flang/lib/Evaluate/fold-real.cpp
index a20f7355861aa5..038ec95a332b82 100644
--- a/flang/lib/Evaluate/fold-real.cpp
+++ b/flang/lib/Evaluate/fold-real.cpp
@@ -166,8 +166,13 @@ Expr<Type<TypeCategory::Real, KIND>> FoldIntrinsicFunction(
     CHECK(args.size() == 2);
     return FoldElementalIntrinsic<T, T, T>(context, std::move(funcRef),
         ScalarFunc<T, T, T>(
-            [](const Scalar<T> &x, const Scalar<T> &y) -> Scalar<T> {
-              return x.HYPOT(y).value;
+            [&](const Scalar<T> &x, const Scalar<T> &y) -> Scalar<T> {
+              ValueWithRealFlags<Scalar<T>> result{x.HYPOT(y)};
+              if (result.flags.test(RealFlag::Overflow)) {
+                context.messages().Say(
+                    "HYPOT intrinsic folding overflow"_warn_en_US);
+              }
+              return result.value;
             }));
   } else if (name == "max") {
     return FoldMINorMAX(context, std::move(funcRef), Ordering::Greater);

diff  --git a/flang/test/Evaluate/errors01.f90 b/flang/test/Evaluate/errors01.f90
index 1ae6c62a4e3ee2..be8700405673c1 100644
--- a/flang/test/Evaluate/errors01.f90
+++ b/flang/test/Evaluate/errors01.f90
@@ -163,6 +163,8 @@ subroutine warnings
     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