From 9164caf25cb210ad0a69357b226e39913aff00d1 Mon Sep 17 00:00:00 2001
From: Harald Anlauf <anlauf@gmx.de>
Date: Mon, 7 Sep 2020 21:41:45 +0200
Subject: [PATCH] PR fortran/96711 - ICE with NINT() for integer(16) result

When rounding a real to the nearest integer, temporarily convert the real
argument to a longer real kind when the result is of type/kind integer(16).

gcc/fortran/ChangeLog:

	* trans-intrinsic.c (build_round_expr): Use temporary with
	appropriate kind for conversion before rounding to nearest
	integer when the result precision is 128 bits.

gcc/testsuite/ChangeLog:

	* gfortran.dg/pr96711.f90: New test.
---
 gcc/fortran/trans-intrinsic.c         | 17 ++++++++++++++--
 gcc/testsuite/gfortran.dg/pr96711.f90 | 28 +++++++++++++++++++++++++++
 2 files changed, 43 insertions(+), 2 deletions(-)
 create mode 100644 gcc/testsuite/gfortran.dg/pr96711.f90

diff --git a/gcc/fortran/trans-intrinsic.c b/gcc/fortran/trans-intrinsic.c
index 2483f016d8e..32fe9886c57 100644
--- a/gcc/fortran/trans-intrinsic.c
+++ b/gcc/fortran/trans-intrinsic.c
@@ -395,11 +395,24 @@ build_round_expr (tree arg, tree restype)
     fn = builtin_decl_for_precision (BUILT_IN_LROUND, argprec);
   else if (resprec <= LONG_LONG_TYPE_SIZE)
     fn = builtin_decl_for_precision (BUILT_IN_LLROUND, argprec);
+  else if (resprec >= argprec && resprec == 128)
+    {
+      /* Search for a real kind suitable as temporary for conversion.  */
+      int kind = -1;
+      for (int i = 0; kind < 0 && gfc_real_kinds[i].kind != 0; i++)
+	if (gfc_real_kinds[i].mode_precision >= resprec)
+	  kind = gfc_real_kinds[i].kind;
+      if (kind < 0)
+	gfc_internal_error ("Could not find real kind with at least %d bits",
+			    resprec);
+      arg = fold_convert (gfc_float128_type_node, arg);
+      fn = gfc_builtin_decl_for_float_kind (BUILT_IN_ROUND, kind);
+    }
   else
     gcc_unreachable ();
 
-  return fold_convert (restype, build_call_expr_loc (input_location,
-						 fn, 1, arg));
+  return convert (restype, build_call_expr_loc (input_location,
+						fn, 1, arg));
 }
 
 
diff --git a/gcc/testsuite/gfortran.dg/pr96711.f90 b/gcc/testsuite/gfortran.dg/pr96711.f90
new file mode 100644
index 00000000000..3761a8ea416
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr96711.f90
@@ -0,0 +1,28 @@
+! { dg-do run }
+! { dg-require-effective-target fortran_integer_16 }
+! { dg-require-effective-target fortran_real_16 }
+! { dg-additional-options "-fdump-tree-original" }
+! { dg-final { scan-tree-dump-times "_gfortran_stop_numeric" 2 "original" } }
+!
+! PR fortran/96711 - ICE on NINT() Function
+
+program p
+  implicit none
+  real(8)                :: x
+  real(16)               :: y
+  integer(16), parameter :: k1 = nint (2 / epsilon (x), kind(k1))
+  integer(16), parameter :: k2 = nint (2 / epsilon (y), kind(k2))
+  integer(16), parameter :: m1 = 9007199254740992_16                    !2**53
+  integer(16), parameter :: m2 = 10384593717069655257060992658440192_16 !2**113
+  integer(16), volatile  :: m
+  x = 2 / epsilon (x)
+  y = 2 / epsilon (y)
+  m = nint (x, kind(m))
+! print *, m
+  if (k1 /= m1) stop 1
+  if (m  /= m1) stop 2
+  m = nint (y, kind(m))
+! print *, m
+  if (k2 /= m2) stop 3
+  if (m  /= m2) stop 4
+end program
-- 
2.30.2