[Bug tree-optimization/103226] [12 Regression] Recent change to copy-headers causes execution failure for gcc.dg/torture/pr80974

[aldyh at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103226

--- Comment #5 from Aldy Hernandez <aldyh at gcc dot gnu.org> ---
FWIW, the *.ch2 dump on both x86-64 and bfin-elf are identical.

This is unlikely to help, but...

In *.ivopts we start seeing differences in the IL:

   <bb 5> [local count: 60236916]:
   e = 1;
+  ivtmp.29_7 = (unsigned int) &g;
   goto <bb 11>; [100.00%]

   <bb 6> [local count: 60236916]:
@@ -593,7 +590,8 @@
     goto <bb 9>; [50.00%]

   <bb 8> [local count: 1625827684]:
-  MEM[(int *)&g + ivtmp.26_25 * 4] = 4;
+  _8 = (void *) ivtmp.29_25;
+  MEM[(int *)_8] = 4;

   <bb 9> [local count: 3251655368]:
   ivtmp_15 = ivtmp_14 - 1;
@@ -603,8 +601,9 @@
     goto <bb 10>; [14.29%]

   <bb 10> [local count: 542132239]:
-  ivtmp.26_10 = ivtmp.26_25 + 1;
-  if (ivtmp.26_10 != 9)
+  h_11 = h_6 + 1;
+  ivtmp.29_10 = ivtmp.29_25 + 4;
+  if (h_11 != 9)
     goto <bb 19>; [90.00%]
   else
     goto <bb 12>; [10.00%]
@@ -612,7 +611,8 @@
   <bb 19> [local count: 487919014]:

   <bb 11> [local count: 542132239]:
-  # ivtmp.26_25 = PHI <ivtmp.26_10(19), 0(5)>
+  # h_6 = PHI <h_11(19), 0(5)>
+  # ivtmp.29_25 = PHI <ivtmp.29_10(19), ivtmp.29_7(5)>
   goto <bb 7>; [100.00%]