[gcc r12-8978] tree-optimization/107865 - ICE with outlining of loops

[gcc r12-8978] tree-optimization/107865 - ICE with outlining of loops

[Richard Biener]

https://gcc.gnu.org/g:09469705318de7a0fe5f10f5d5b92870d3fada6e

commit r12-8978-g09469705318de7a0fe5f10f5d5b92870d3fada6e
Author: Richard Biener <rguenther@suse.de>
Date:   Fri Nov 25 08:27:42 2022 +0100

    tree-optimization/107865 - ICE with outlining of loops
    
    The following makes sure to clear loops number of iterations when
    outlining them as part of a SESE region as can happen with
    auto-parallelization.  The referenced SSA names become stale otherwise.
    
            PR tree-optimization/107865
            * tree-cfg.cc (move_sese_region_to_fn): Free the number of
            iterations of moved loops.
    
            * gfortran.dg/graphite/pr107865.f90: New testcase.
    
    (cherry picked from commit bcc2449384f2092cbdf5d6ac2357aeabe3212b2e)

Diff:
---
 gcc/testsuite/gfortran.dg/graphite/pr107865.f90 | 18 ++++++++++++++++++
 gcc/tree-cfg.cc                                 |  2 ++
 2 files changed, 20 insertions(+)

diff --git a/gcc/testsuite/gfortran.dg/graphite/pr107865.f90 b/gcc/testsuite/gfortran.dg/graphite/pr107865.f90
new file mode 100644
index 00000000000..6bddb17a1be
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/graphite/pr107865.f90
@@ -0,0 +1,18 @@
+! { dg-do compile }
+! { dg-options "-O1 -floop-parallelize-all -ftree-parallelize-loops=2" }
+
+      SUBROUTINE FNC (F)
+
+      IMPLICIT REAL (A-H)
+      DIMENSION F(N)
+
+      DO I = 1, 6
+         DO J = 1, 6
+            IF (J .NE. I) THEN
+               F(I) = F(I) + 1
+            END IF
+         END DO
+      END DO
+
+      RETURN
+      END
diff --git a/gcc/tree-cfg.cc b/gcc/tree-cfg.cc
index c0824e34802..05fc4514714 100644
--- a/gcc/tree-cfg.cc
+++ b/gcc/tree-cfg.cc
@@ -7737,6 +7737,8 @@ move_sese_region_to_fn (struct function *dest_cfun, basic_block entry_bb,
       if (bb->loop_father->header == bb)
 	{
 	  class loop *this_loop = bb->loop_father;
+	  /* Avoid the need to remap SSA names used in nb_iterations.  */
+	  free_numbers_of_iterations_estimates (this_loop);
 	  class loop *outer = loop_outer (this_loop);
 	  if (outer == loop
 	      /* If the SESE region contains some bbs ending with