On Thu, Nov 07, 2013 at 10:32:10AM +0100, Richard Biener wrote:
> I'm looking for adjusting of live compute - either by adjusting the
> algorithm or by special casing the latches. Like for example
> with the following (untested, needs cleanup - the PHI processing
> can be factored out from find_assert_locations_1 and re-used):
>
> @@ -5904,6 +5898,27 @@ find_assert_locations (void)
> for (i = 0; i < rpo_cnt; ++i)
> bb_rpo[rpo[i]] = i;
>
> + /* Pre-seed loop latch liveness from loop header PHI nodes. Due to
> + the order we compute liveness and insert asserts we otherwise
> + fail to insert asserts into the loop latch. */
> + loop_p loop;
> + loop_iterator li;
> + FOR_EACH_LOOP (li, loop, 0)
> + {
> + i = loop->latch->index;
> + live[i] = sbitmap_alloc (num_ssa_names);
> + bitmap_clear (live[i]);
> + for (gimple_stmt_iterator gsi = gsi_start_phis (loop->header);
> + !gsi_end_p (gsi); gsi_next (&gsi))
> + {
> + gimple phi = gsi_stmt (gsi);
> + if (virtual_operand_p (gimple_phi_result (phi)))
> + continue;
> + for (unsigned j = 0; j < gimple_phi_num_args (phi); ++j)
> + if (TREE_CODE (gimple_phi_arg_def (phi, j)) == SSA_NAME)
> + bitmap_set_bit (live[i], SSA_NAME_VERSION
> (gimple_phi_arg_def (phi, j)));
> + }
> + }
LGTM, except that I think we should only care about phi args from the
latch -> header edge, not others and IMHO it is memory waste to allocate
sbitmap even when we wouldn't add anything. So, I'm going to
rebootstrap/regtest the following (including new testcase Jeff asked for):
2013-11-07 Richard Biener <[email protected]>
Jakub Jelinek <[email protected]>
* tree-vrp.c (find_assert_locations): Pre-seed live bitmaps for loop
latches from header PHI arguments from the latch edge.
* gcc.dg/unroll_1.c: Add -fno-tree-vrp to dg-options.
* gcc.dg/unroll_2.c: Likewise.
* gcc.dg/unroll_3.c: Likewise.
* gcc.dg/unroll_4.c: Likewise.
* gcc.dg/vrp90.c: New test.
--- gcc/tree-vrp.c.jj 2013-11-06 16:58:04.675678567 +0100
+++ gcc/tree-vrp.c 2013-11-07 10:59:38.841283931 +0100
@@ -5906,6 +5906,34 @@ find_assert_locations (void)
for (i = 0; i < rpo_cnt; ++i)
bb_rpo[rpo[i]] = i;
+ /* Pre-seed loop latch liveness from loop header PHI nodes. Due to
+ the order we compute liveness and insert asserts we otherwise
+ fail to insert asserts into the loop latch. */
+ loop_p loop;
+ loop_iterator li;
+ FOR_EACH_LOOP (li, loop, 0)
+ {
+ i = loop->latch->index;
+ unsigned int j = find_edge (loop->latch, loop->header)->dest_idx;
+ for (gimple_stmt_iterator gsi = gsi_start_phis (loop->header);
+ !gsi_end_p (gsi); gsi_next (&gsi))
+ {
+ gimple phi = gsi_stmt (gsi);
+ if (virtual_operand_p (gimple_phi_result (phi)))
+ continue;
+ tree arg = gimple_phi_arg_def (phi, j);
+ if (TREE_CODE (arg) == SSA_NAME)
+ {
+ if (live[i] == NULL)
+ {
+ live[i] = sbitmap_alloc (num_ssa_names);
+ bitmap_clear (live[i]);
+ }
+ bitmap_set_bit (live[i], SSA_NAME_VERSION (arg));
+ }
+ }
+ }
+
need_asserts = false;
for (i = rpo_cnt - 1; i >= 0; --i)
{
--- gcc/testsuite/gcc.dg/unroll_1.c.jj 2013-09-09 11:32:36.000000000 +0200
+++ gcc/testsuite/gcc.dg/unroll_1.c 2013-11-06 17:10:52.900722932 +0100
@@ -1,5 +1,5 @@
/* { dg-do compile } */
-/* { dg-options "-O2 -fdump-rtl-loop2_unroll=stderr -fno-peel-loops
-fdisable-tree-cunroll -fdisable-tree-cunrolli -fenable-rtl-loop2_unroll" } */
+/* { dg-options "-O2 -fdump-rtl-loop2_unroll=stderr -fno-peel-loops
-fno-tree-vrp -fdisable-tree-cunroll -fdisable-tree-cunrolli
-fenable-rtl-loop2_unroll" } */
unsigned a[100], b[100];
inline void bar()
--- gcc/testsuite/gcc.dg/unroll_2.c.jj 2013-08-30 14:38:39.000000000 +0200
+++ gcc/testsuite/gcc.dg/unroll_2.c 2013-11-06 17:10:30.751845504 +0100
@@ -1,5 +1,5 @@
/* { dg-do compile } */
-/* { dg-options "-O2 -fdump-rtl-loop2_unroll -fno-peel-loops
-fdisable-tree-cunroll=foo -fdisable-tree-cunrolli=foo
-fenable-rtl-loop2_unroll" } */
+/* { dg-options "-O2 -fdump-rtl-loop2_unroll -fno-peel-loops -fno-tree-vrp
-fdisable-tree-cunroll=foo -fdisable-tree-cunrolli=foo
-fenable-rtl-loop2_unroll" } */
unsigned a[100], b[100];
inline void bar()
--- gcc/testsuite/gcc.dg/unroll_3.c.jj 2013-08-30 14:38:39.000000000 +0200
+++ gcc/testsuite/gcc.dg/unroll_3.c 2013-11-06 17:10:38.864800338 +0100
@@ -1,5 +1,5 @@
/* { dg-do compile } */
-/* { dg-options "-O2 -fdump-rtl-loop2_unroll -fno-peel-loops
-fdisable-tree-cunroll -fdisable-tree-cunrolli -fenable-rtl-loop2_unroll=foo" }
*/
+/* { dg-options "-O2 -fdump-rtl-loop2_unroll -fno-peel-loops -fno-tree-vrp
-fdisable-tree-cunroll -fdisable-tree-cunrolli -fenable-rtl-loop2_unroll=foo" }
*/
unsigned a[100], b[100];
inline void bar()
--- gcc/testsuite/gcc.dg/unroll_4.c.jj 2013-08-30 14:38:40.000000000 +0200
+++ gcc/testsuite/gcc.dg/unroll_4.c 2013-11-06 17:11:03.816665603 +0100
@@ -1,5 +1,5 @@
/* { dg-do compile } */
-/* { dg-options "-O2 -fdump-rtl-loop2_unroll -fno-peel-loops
-fdisable-tree-cunroll -fdisable-tree-cunrolli -fenable-rtl-loop2_unroll=foo2"
} */
+/* { dg-options "-O2 -fdump-rtl-loop2_unroll -fno-peel-loops -fno-tree-vrp
-fdisable-tree-cunroll -fdisable-tree-cunrolli -fenable-rtl-loop2_unroll=foo2"
} */
unsigned a[100], b[100];
inline void bar()
--- gcc/testsuite/gcc.dg/tree-ssa/vrp90.c.jj 2013-11-07 11:01:55.137535477
+0100
+++ gcc/testsuite/gcc.dg/tree-ssa/vrp90.c 2013-11-07 11:02:35.189335924
+0100
@@ -0,0 +1,36 @@
+/* { dg-do link } */
+/* { dg-options "-O2 -fdump-tree-vrp1" } */
+/* { dg-final { scan-tree-dump-not "link_error" "vrp1"} } */
+/* { dg-final { cleanup-tree-dump "vrp1" } } */
+
+extern void link_error (void);
+
+__attribute__((noinline, noclone)) int
+foo (unsigned int n, int r)
+{
+ int i;
+ if (n > 0)
+ {
+ asm ("");
+ if (n < 10)
+ {
+ asm ("");
+ do
+ {
+ --n;
+ r *= 2;
+ if (n >= 9)
+ link_error ();
+ }
+ while (n > 0);
+ }
+ }
+ return r + n;
+}
+
+int
+main ()
+{
+ foo (7, 2);
+ return 0;
+}
Jakub
