The testcase shows that when cleaning up the CFG we can end up
with broken LC SSA (for virtual operands with the testcase). The
case here involves deleting a loop after which it is not enough
to scan the blocks with changed loop depth for SSA uses that need
to be rewritten. So make fix_loop_sturcture return the sum of
the number of new loops and the number of deleted loops.
Bootstrap and regtest pending on x86_64-unknown-linux-gnu.
PR tree-optimization/106182
* loop-init.cc (fix_loop_structure): Return the number
of newly discovered plus the number of deleted loops.
* tree-cfgcleanup.cc (repair_loop_structures): Adjust
variable name.
* gcc.dg/torture/pr106182.c: New testcase.
---
gcc/loop-init.cc | 10 +++++-----
gcc/testsuite/gcc.dg/torture/pr106182.c | 18 ++++++++++++++++++
gcc/tree-cfgcleanup.cc | 6 +++---
3 files changed, 26 insertions(+), 8 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/torture/pr106182.c
diff --git a/gcc/loop-init.cc b/gcc/loop-init.cc
index 648aa290916..b9e07973dd6 100644
--- a/gcc/loop-init.cc
+++ b/gcc/loop-init.cc
@@ -194,7 +194,7 @@ loop_fini_done:
If CHANGED_BBS is not NULL, basic blocks whose loop depth has changed are
marked in it.
- Returns the number of new discovered loops. */
+ Returns the number of new discovered plus the number of removed loops. */
unsigned
fix_loop_structure (bitmap changed_bbs)
@@ -277,7 +277,7 @@ fix_loop_structure (bitmap changed_bbs)
}
/* Finally free deleted loops. */
- bool any_deleted = false;
+ unsigned n_deleted = 0;
class loop *loop;
FOR_EACH_VEC_ELT (*get_loops (cfun), i, loop)
if (loop && loop->header == NULL)
@@ -311,12 +311,12 @@ fix_loop_structure (bitmap changed_bbs)
}
(*get_loops (cfun))[i] = NULL;
flow_loop_free (loop);
- any_deleted = true;
+ n_deleted++;
}
/* If we deleted loops then the cached scalar evolutions refering to
those loops become invalid. */
- if (any_deleted && scev_initialized_p ())
+ if (n_deleted > 0 && scev_initialized_p ())
scev_reset_htab ();
loops_state_clear (LOOPS_NEED_FIXUP);
@@ -328,7 +328,7 @@ fix_loop_structure (bitmap changed_bbs)
timevar_pop (TV_LOOP_INIT);
- return number_of_loops (cfun) - old_nloops;
+ return number_of_loops (cfun) - old_nloops + n_deleted;
}
/* The RTL loop superpass. The actual passes are subpasses. See passes.cc for
diff --git a/gcc/testsuite/gcc.dg/torture/pr106182.c
b/gcc/testsuite/gcc.dg/torture/pr106182.c
new file mode 100644
index 00000000000..6b5c2493fd6
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr106182.c
@@ -0,0 +1,18 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-funswitch-loops" } */
+
+short var_32;
+int test_var_0;
+unsigned char test_var_6;
+char test_var_13;
+void test(int var_2)
+{
+ for (;;)
+ for (short i_7; i_7 < test_var_13; i_7 += 1)
+ for (; test_var_0;) {
+ for (; var_2;)
+ var_32 = 0;
+ for (char i_19; i_19 < test_var_6 + 135; i_19 += 200)
+ ;
+ }
+}
diff --git a/gcc/tree-cfgcleanup.cc b/gcc/tree-cfgcleanup.cc
index a6d0bf2c40a..3b24e021b6b 100644
--- a/gcc/tree-cfgcleanup.cc
+++ b/gcc/tree-cfgcleanup.cc
@@ -1170,13 +1170,13 @@ static void
repair_loop_structures (void)
{
bitmap changed_bbs;
- unsigned n_new_loops;
+ unsigned n_new_or_deleted_loops;
calculate_dominance_info (CDI_DOMINATORS);
timevar_push (TV_REPAIR_LOOPS);
changed_bbs = BITMAP_ALLOC (NULL);
- n_new_loops = fix_loop_structure (changed_bbs);
+ n_new_or_deleted_loops = fix_loop_structure (changed_bbs);
/* This usually does nothing. But sometimes parts of cfg that originally
were inside a loop get out of it due to edge removal (since they
@@ -1184,7 +1184,7 @@ repair_loop_structures (void)
irreducible loop can become reducible - in this case force a full
rewrite into loop-closed SSA form. */
if (loops_state_satisfies_p (LOOP_CLOSED_SSA))
- rewrite_into_loop_closed_ssa (n_new_loops ? NULL : changed_bbs,
+ rewrite_into_loop_closed_ssa (n_new_or_deleted_loops ? NULL : changed_bbs,
TODO_update_ssa);
BITMAP_FREE (changed_bbs);
--
2.35.3
