[flang-commits] [PATCH] D156754: [flang] Fix crash in folding of DPROD() with non-scalar arguments

[Peter Klausler via Phabricator via flang-commits]

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

DPROD(x,y) is defined as DBLE(x)*DBLE(y) and that's exactly how
the implementation of its rewriting and possible folding should 
be implemented, instead of the current code that only works when
both arguments are scalar and crashes otherwise.


https://reviews.llvm.org/D156754

Files:
  flang/lib/Evaluate/fold-real.cpp
  flang/test/Evaluate/fold-dprod.f90


Index: flang/test/Evaluate/fold-dprod.f90
===================================================================
--- /dev/null
+++ flang/test/Evaluate/fold-dprod.f90
@@ -0,0 +1,8 @@
+! RUN: %python %S/test_folding.py %s %flang_fc1
+! Tests folding of DPROD()
+module m
+  logical, parameter :: test_kind = kind(dprod(2., 3.)) == kind(0.d0)
+  logical, parameter :: test_ss = dprod(2., 3.) == 6.d0
+  logical, parameter :: test_sv = all(dprod(2., [3.,4.]) == [6.d0,8.d0])
+  logical, parameter :: test_vv = all(dprod([2.,3.], [4.,5.]) == [8.d0,15.0d0])
+end
Index: flang/lib/Evaluate/fold-real.cpp
===================================================================
--- flang/lib/Evaluate/fold-real.cpp
+++ flang/lib/Evaluate/fold-real.cpp
@@ -149,10 +149,15 @@
   } else if (name == "dot_product") {
     return FoldDotProduct<T>(context, std::move(funcRef));
   } else if (name == "dprod") {
-    if (auto scalars{GetScalarConstantArguments<T, T>(context, args)}) {
-      return Fold(context,
-          Expr<T>{Multiply<T>{
-              Expr<T>{std::get<0>(*scalars)}, Expr<T>{std::get<1>(*scalars)}}});
+    // Rewrite DPROD(x,y) -> DBLE(x)*DBLE(y)
+    if (args.at(0) && args.at(1)) {
+      const auto *xExpr{args[0]->UnwrapExpr()};
+      const auto *yExpr{args[1]->UnwrapExpr()};
+      if (xExpr && yExpr) {
+        return Fold(context,
+            ToReal<T::kind>(context, common::Clone(*xExpr)) *
+                ToReal<T::kind>(context, common::Clone(*yExpr)));
+      }
     }
   } else if (name == "epsilon") {
     return Expr<T>{Scalar<T>::EPSILON()};


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