[PR97684] IRA: Recalculate pseudo classes if we added new pseduos since last calculation before updating equiv regs

update_equiv_regs can use reg classes of pseudos and they are set up in
register pressure sensitive scheduling and loop invariant motion and in
live range shrinking.  This info can become obsolete if we add new pseudos
since the last set up.  Recalculate it again if the new pseudos were
added.

gcc/ChangeLog:

	PR rtl-optimization/97684
	* ira.c (ira): Call ira_set_pseudo_classes before
	update_equiv_regs when it is necessary.

gcc/testsuite/ChangeLog:

	PR rtl-optimization/97684
	* gcc.target/i386/pr97684.c: New.

2 files changed, 33 insertions, 3 deletions

diff --git a/gcc/ira.c b/gcc/ira.c
index f0bdbc8..c32ecf81 100644
--- a/gcc/ira.c
+++ b/gcc/ira.c
@@ -5566,6 +5566,15 @@ ira (FILE *f)
   if (warn_clobbered)
     generate_setjmp_warnings ();
 
+  /* update_equiv_regs can use reg classes of pseudos and they are set up in
+     register pressure sensitive scheduling and loop invariant motion and in
+     live range shrinking.  This info can become obsolete if we add new pseudos
+     since the last set up.  Recalculate it again if the new pseudos were
+     added.  */
+  if (resize_reg_info () && (flag_sched_pressure || flag_live_range_shrinkage
+			     || flag_ira_loop_pressure))
+    ira_set_pseudo_classes (true, ira_dump_file);
+
   init_alias_analysis ();
   loop_optimizer_init (AVOID_CFG_MODIFICATIONS);
   reg_equiv = XCNEWVEC (struct equivalence, max_reg_num ());
@@ -5610,9 +5619,6 @@ ira (FILE *f)
       regstat_recompute_for_max_regno ();
     }
 
-  if (resize_reg_info () && flag_ira_loop_pressure)
-    ira_set_pseudo_classes (true, ira_dump_file);
-
   setup_reg_equiv ();
   grow_reg_equivs ();
   setup_reg_equiv_init ();
diff --git a/gcc/testsuite/gcc.target/i386/pr97684.c b/gcc/testsuite/gcc.target/i386/pr97684.c
new file mode 100644
index 0000000..983bf53
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr97684.c
@@ -0,0 +1,24 @@
+/* PR rtl-optimization/97684 */
+/* { dg-do compile } */
+/* { dg-options "-O1 -flive-range-shrinkage -fschedule-insns -fselective-scheduling -funroll-all-loops -fno-web" } */
+
+void
+c5 (double);
+
+void
+g4 (int *n4)
+{
+  double lp = 0.0;
+  int fn;
+
+  for (fn = 0; fn < 18; ++fn)
+    {
+      int as;
+
+      as = __builtin_abs (n4[fn]);
+      if (as > lp)
+        lp = as;
+    }
+
+  c5 (lp);
+}