Re: [PATCH, PR rtl-optimization/71148] Avoid cleanup_cfg called with invalidated dominance info

[Ilya Enkovich <enkovich dot gnu at gmail dot com>]

On 19 May 09:57, Richard Biener wrote:
> On Wed, May 18, 2016 at 6:17 PM, Ilya Enkovich <enkovich.gnu@gmail.com> wrote:
> > Hi,
> >
> > This patch resolves PR71148 by releasing dominance info before
> > cleanup_cfg calls to avoid attempts to fixup invalid dominance
> > info.
> >
> > Dominance info handling in cleanup_cfg looks weird though.  It
> > tries to fix it but can invalidate it at the same time (PR71084).
> > We should probably do something with that.
> >
> > Tracker is P1 and this patch may be OK solution for now.
> >
> > Bootstrapped and regtested on x86_64-pc-linux-gnu.  Ok for trunk?
> 
> Hum... all this dancing with CSE looks bogus to me.  Does CSE itself
> need dominance info?  If not then unconditionally free it at its start.
> 
> Richard.
> 

Here it is.  OK if testing pass?

Thanks,
Ilya
--
gcc/

2016-05-19  Ilya Enkovich  <ilya.enkovich@intel.com>

	* cse.c (cse_main): Free dominance info.
	(rest_of_handle_cse): Don't free dominance info.
	(rest_of_handle_cse2): Likewise.
	(rest_of_handle_cse_after_global_opts): Likewise.

gcc/testsuite/

2016-05-19  Ilya Enkovich  <ilya.enkovich@intel.com>

	* gcc.dg/pr71148.c: New test.


diff --git a/gcc/cse.c b/gcc/cse.c
index 322e352..84082fb 100644
--- a/gcc/cse.c
+++ b/gcc/cse.c
@@ -6669,6 +6669,11 @@ cse_main (rtx_insn *f ATTRIBUTE_UNUSED, int nregs)
   int *rc_order = XNEWVEC (int, last_basic_block_for_fn (cfun));
   int i, n_blocks;
 
+  /* CSE doesn't use dominance info but can invalidate it in different ways.
+     For simplicity free dominance info here.  */
+  if (dom_info_available_p (CDI_DOMINATORS))
+    free_dominance_info (CDI_DOMINATORS);
+
   df_set_flags (DF_LR_RUN_DCE);
   df_note_add_problem ();
   df_analyze ();
@@ -7568,9 +7573,6 @@ rest_of_handle_cse (void)
   else if (tem == 1 || optimize > 1)
     cse_cfg_altered |= cleanup_cfg (0);
 
-  if (cse_cfg_altered && dom_info_available_p (CDI_DOMINATORS))
-    free_dominance_info (CDI_DOMINATORS);
-
   return 0;
 }
 
@@ -7640,9 +7642,6 @@ rest_of_handle_cse2 (void)
   else if (tem == 1)
     cse_cfg_altered |= cleanup_cfg (0);
 
-  if (cse_cfg_altered && dom_info_available_p (CDI_DOMINATORS))
-    free_dominance_info (CDI_DOMINATORS);
-
   cse_not_expected = 1;
   return 0;
 }
@@ -7717,9 +7716,6 @@ rest_of_handle_cse_after_global_opts (void)
   else if (tem == 1)
     cse_cfg_altered |= cleanup_cfg (0);
 
-  if (cse_cfg_altered && dom_info_available_p (CDI_DOMINATORS))
-    free_dominance_info (CDI_DOMINATORS);
-
   flag_cse_follow_jumps = save_cfj;
   return 0;
 }
diff --git a/gcc/testsuite/gcc.dg/pr71148.c b/gcc/testsuite/gcc.dg/pr71148.c
new file mode 100644
index 0000000..6aa4920
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr71148.c
@@ -0,0 +1,46 @@
+/* PR rtl-optimization/71148 */
+/* { dg-do compile } */
+/* { dg-options "-O3 -funroll-loops" } */
+
+int rh, ok, kq, fu;
+
+void
+js (int cs)
+{
+  rh = fu;
+  if (fu != 0)
+    {
+      cs /= 3;
+      if (cs <= 0)
+        {
+          int z9;
+          for (z9 = 0; z9 < 2; ++z9)
+            {
+              z9 += cs;
+              ok += z9;
+              fu += ok;
+            }
+        }
+    }
+}
+
+void
+vy (int s3)
+{
+  int yo, g2 = 0;
+ sd:
+  js (g2);
+  for (yo = 0; yo < 2; ++yo)
+    {
+      if (fu != 0)
+        goto sd;
+      kq += (s3 != (g2 ? s3 : 0));
+      for (s3 = 0; s3 < 72; ++s3)
+        g2 *= (~0 - 1);
+      g2 -= yo;
+    }
+  for (fu = 0; fu < 18; ++fu)
+    for (yo = 0; yo < 17; ++yo)
+      if (g2 < 0)
+        goto sd;
+}