This fixes PR57488 - clearing NEW sets before each insert iteration
ensures we don't propagate memory accesses across back-edges into
regions where that would not be valid.
Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.
Richard.
2013-06-24 Richard Biener <rguent...@suse.de>
PR tree-optimization/57488
* tree-ssa-pre.c (insert): Clear NEW sets before each iteration.
* gcc.dg/torture/pr57488.c: New testcase.
Index: gcc/tree-ssa-pre.c
===================================================================
*** gcc/tree-ssa-pre.c (revision 200237)
--- gcc/tree-ssa-pre.c (working copy)
*************** insert (void)
*** 3665,3670 ****
--- 3666,3677 ----
if (dump_file && dump_flags & TDF_DETAILS)
fprintf (dump_file, "Starting insert iteration %d\n", num_iterations);
new_stuff = insert_aux (ENTRY_BLOCK_PTR);
+
+ /* Clear the NEW sets before the next iteration. We have already
+ fully propagated its contents. */
+ if (new_stuff)
+ FOR_ALL_BB (bb)
+ bitmap_set_free (NEW_SETS (bb));
}
statistics_histogram_event (cfun, "insert iterations", num_iterations);
}
Index: gcc/testsuite/gcc.dg/torture/pr57488.c
===================================================================
*** gcc/testsuite/gcc.dg/torture/pr57488.c (revision 0)
--- gcc/testsuite/gcc.dg/torture/pr57488.c (working copy)
***************
*** 0 ****
--- 1,58 ----
+ /* { dg-do run } */
+
+ extern void abort (void);
+
+ int i, j, *pj = &j, **ppj = &pj;
+ int x, *px = &x;
+
+ short s, *ps = &s, k;
+
+ unsigned short u, *pu = &u, **ppu = &pu;
+
+ char c, *pc = &c;
+
+ unsigned char v = 48;
+
+ static int
+ bar (int p)
+ {
+ p = k;
+ *px = **ppu = i;
+ *ppj = &p;
+ if (**ppj)
+ *pj = p;
+ return p;
+ }
+
+ void __attribute__((noinline))
+ foo ()
+ {
+ for (; i <= 3; i++)
+ for (; j; j--);
+
+ u ^= bar (*pj);
+
+ for (k = 1; k >= 0; k--)
+ {
+ int l;
+ bar (0);
+ for (l = 1; l < 5; l++)
+ {
+ int m;
+ for (m = 6; m; m--)
+ {
+ v--;
+ *ps = *pc;
+ }
+ }
+ }
+ }
+
+ int
+ main ()
+ {
+ foo ();
+ if (v != 0)
+ abort ();
+ return 0;
+ }
