From bee8619ad0ac3bd27b7c8dc5819b83a5e8e147a0 Mon Sep 17 00:00:00 2001
From: Harald Anlauf <anlauf@gmx.de>
Date: Fri, 4 Jun 2021 19:23:48 +0200
Subject: [PATCH] Fortran - ICE in inline_matmul_assign

Restrict inlining of matmul to those cases where assignment to the
result array does not need special treatment.

gcc/fortran/ChangeLog:

	PR fortran/99839
	* frontend-passes.c (inline_matmul_assign): Do not inline matmul
	if the assignment to the resulting array if it is not of canonical
	type (real/integer/complex/logical).

gcc/testsuite/ChangeLog:

	PR fortran/99839
	* gfortran.dg/inline_matmul_25.f90: New test.
---
 gcc/fortran/frontend-passes.c                  | 13 +++++++++++++
 gcc/testsuite/gfortran.dg/inline_matmul_25.f90 |  9 +++++++++
 2 files changed, 22 insertions(+)
 create mode 100644 gcc/testsuite/gfortran.dg/inline_matmul_25.f90

diff --git a/gcc/fortran/frontend-passes.c b/gcc/fortran/frontend-passes.c
index 34fb22c57449..72a4e0410b1c 100644
--- a/gcc/fortran/frontend-passes.c
+++ b/gcc/fortran/frontend-passes.c
@@ -4193,6 +4193,19 @@ inline_matmul_assign (gfc_code **c, int *walk_subtrees,
   if (m_case == none)
     return 0;
 
+  /* We only handle assignment to numeric or logical variables.  */
+  switch(expr1->ts.type)
+    {
+    case BT_INTEGER:
+    case BT_LOGICAL:
+    case BT_REAL:
+    case BT_COMPLEX:
+      break;
+
+    default:
+      return 0;
+    }
+
   ns = insert_block ();
 
   /* Assign the type of the zero expression for initializing the resulting
diff --git a/gcc/testsuite/gfortran.dg/inline_matmul_25.f90 b/gcc/testsuite/gfortran.dg/inline_matmul_25.f90
new file mode 100644
index 000000000000..df8ad06c123e
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/inline_matmul_25.f90
@@ -0,0 +1,9 @@
+! { dg-do compile }
+! { dg-options "-ffrontend-optimize" }
+! PR fortran/99839 - ICE in inline_matmul_assign
+
+program p
+  real :: x(3, 3) = 1.0
+  class(*), allocatable :: z(:, :)
+  z = matmul(x, x)
+end
-- 
2.47.2