[gcc r13-4268] c: Fix compile time hog in c_genericize [PR107127]

[Jakub Jelinek <jakub@gcc.gnu.org>]

https://gcc.gnu.org/g:8a0fce6a51915c29584427fd376b40073c328090

commit r13-4268-g8a0fce6a51915c29584427fd376b40073c328090
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Wed Nov 23 19:09:31 2022 +0100

    c: Fix compile time hog in c_genericize [PR107127]
    
    The complex multiplications result in deeply nested set of many SAVE_EXPRs,
    which takes even on fast machines over 5 minutes to walk.
    This patch fixes that by using walk_tree_without_duplicates where it is
    instant.
    
    2022-11-23  Andrew Pinski  <apinski@marvell.com>
                Jakub Jelinek  <jakub@redhat.com>
    
            PR c/107127
            * c-gimplify.cc (c_genericize): Use walk_tree_without_duplicates
            instead of walk_tree for c_genericize_control_r.
    
            * gcc.dg/pr107127.c: New test.

Diff:
---
 gcc/c-family/c-gimplify.cc      |  4 ++--
 gcc/testsuite/gcc.dg/pr107127.c | 12 ++++++++++++
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/gcc/c-family/c-gimplify.cc b/gcc/c-family/c-gimplify.cc
index 039a4b93230..0034d41d33a 100644
--- a/gcc/c-family/c-gimplify.cc
+++ b/gcc/c-family/c-gimplify.cc
@@ -572,8 +572,8 @@ c_genericize (tree fndecl)
       bc_state_t save_state;
       push_cfun (DECL_STRUCT_FUNCTION (fndecl));
       save_bc_state (&save_state);
-      walk_tree (&DECL_SAVED_TREE (fndecl), c_genericize_control_r,
-		 NULL, NULL);
+      walk_tree_without_duplicates (&DECL_SAVED_TREE (fndecl),
+				    c_genericize_control_r, NULL);
       restore_bc_state (&save_state);
       pop_cfun ();
     }
diff --git a/gcc/testsuite/gcc.dg/pr107127.c b/gcc/testsuite/gcc.dg/pr107127.c
new file mode 100644
index 00000000000..f7ae87db70e
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr107127.c
@@ -0,0 +1,12 @@
+/* PR c/107127 */
+/* { dg-do compile } */
+/* { dg-options "" } */
+
+int *v;
+
+_Complex double
+foo (_Complex double a, double b, double c)
+{
+  return v[0] / ((((c * (0 - 0 / a + 699.0 + 7.05 - 286.0 - +-4.65 + 1.57 + 0) * 0.1 - 3.28 + 4.22 + 0.1)) * b + 5.06)
+		 * 1.23 * 8.0 * 12.0 * 16.0 * 2.0 * 2.0 * 0.25 * 0.125 * 18.2 * -15.25 * 0.0001
+		 * 42.0 * 0.012 - 8.45 + 0 + 88.0 + 6.96 + 867.0 + 9.10 - 7.04 * -1.0);