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From: "hubicka at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug testsuite/109596] [14 Regression] Lots of guality testcase
 fails on x86_64 after r14-162-gcda246f8b421ba
Date: Tue, 19 Mar 2024 15:47:48 +0000
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X-Bugzilla-Component: testsuite
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D109596

--- Comment #6 from Jan Hubicka <hubicka at gcc dot gnu.org> ---
On this testcase trunk does get same dump as gcc13 for pass just before ch2

with ch2 we get:
@@ -192,9 +236,8 @@
   # DEBUG BEGIN_STMT
   goto <bb 5>; [100.00%]

-  <bb 3> [local count: 954449105]:
+  <bb 3> [local count: 954449104]:
   # j_15 =3D PHI <j_9(3), 0(5)>
-  # DEBUG j =3D> j_15
   # DEBUG BEGIN_STMT
   a[b_14][j_15] =3D 0;
   # DEBUG BEGIN_STMT
@@ -203,29 +246,30 @@
   # DEBUG j =3D> j_9
   # DEBUG BEGIN_STMT
   if (j_9 <=3D 7)
-    goto <bb 3>; [88.89%]
+    goto <bb 3>; [87.50%]
   else
-    goto <bb 4>; [11.11%]
+    goto <bb 4>; [12.50%]

   <bb 4> [local count: 119292720]:
+  # DEBUG j =3D> 0
   # DEBUG BEGIN_STMT
   b_7 =3D b_14 + 1;
   # DEBUG b =3D> b_7
   # DEBUG b =3D> b_7
   # DEBUG BEGIN_STMT
   if (b_7 <=3D 6)
-    goto <bb 5>; [87.50%]
+    goto <bb 5>; [85.71%]
   else
-    goto <bb 6>; [12.50%]
+    goto <bb 6>; [14.29%]

   <bb 5> [local count: 119292720]:
   # b_14 =3D PHI <b_7(4), 0(2)>
-  # DEBUG b =3D> b_14
   # DEBUG j =3D> 0
   # DEBUG BEGIN_STMT
   goto <bb 3>; [100.00%]

   <bb 6> [local count: 17041817]:
+  # DEBUG b =3D> 0
   # DEBUG BEGIN_STMT
   optimize_me_not ();
   # DEBUG BEGIN_STMT


So in addition to updating BB profile, we indeed end up moving debug statem=
ents
around.

The change of dump is:
+  Analyzing: if (b_1 <=3D 6)
+    Will eliminate peeled conditional in bb 6.
+    May duplicate bb 6
+  Not duplicating bb 8: it is single succ.
+  Analyzing: if (j_2 <=3D 7)
+    Will eliminate peeled conditional in bb 4.
+    May duplicate bb 4
+  Not duplicating bb 3: it is single succ.
 Loop 2 is not do-while loop: latch is not empty.
+    Duplicating header BB to obtain do-while loop
 Copying headers of loop 1
     Will duplicate bb 6
-  Not duplicating bb 8: it is single succ.
-Duplicating header of the loop 1 up to edge 6->8, 2 insns.
+Duplicating header of the loop 1 up to edge 6->7
 Loop 1 is do-while loop
 Loop 1 is now do-while loop.
+Exit count: 17041817 (estimated locally)
+Entry count: 17041817 (estimated locally)
+Peeled all exits: decreased number of iterations of loop 1 by 1.
 Copying headers of loop 2
     Will duplicate bb 4
-  Not duplicating bb 3: it is single succ.
-Duplicating header of the loop 2 up to edge 4->3, 2 insns.
+Duplicating header of the loop 2 up to edge 4->5
 Loop 2 is do-while loop
 Loop 2 is now do-while loop.
+Exit count: 119292720 (estimated locally)
+Entry count: 119292720 (estimated locally)
+Peeled all exits: decreased number of iterations of loop 2 by 1.

Dumps moved around, but we do same duplicaitons as before (BB6 and BB4 to
eliminate the conditionals).

  <bb 4> [local count: 1073741824]:
  # j_2 =3D PHI <0(8), j_9(3)>
  # DEBUG j =3D> j_2
  # DEBUG BEGIN_STMT
  if (j_2 <=3D 7)
    goto <bb 3>; [88.89%]
  else
    goto <bb 5>; [11.11%]

  <bb 6> [local count: 136334537]:
  # b_1 =3D PHI <0(2), b_7(5)>
  # DEBUG b =3D> b_1
  # DEBUG BEGIN_STMT
  if (b_1 <=3D 6)
    goto <bb 8>; [87.50%]
  else
    goto <bb 7>; [12.50%]=