Hi All,
The failures on -m32 on x86 show that the checks at the top level in
tree_ssa_phiopt_worker aren't enough for diamond_p.
In minmax_replacement we perform the additional validation of the shape but by
then it's too late to catch these case.
This patch changes it so we check that for a diamond shape we check that the
edges we're operation on must result in the same destination BB.
We also enforce that for a diamond the middle BBs must have a single successor,
this is because the remainder of the code always follows EDGE_SUCC 0. If there
are more than 1 successor then the edge we follow could be not part of the
diamond so just reject it early on.
I also remove the assert after the use of gimple_phi_arg_def as this function
can't return NULL. if the index is out of range it already breaks on an assert
inside the gimple_phi_arg_def, so we never hit this assert.
Bootstrapped Regtested on aarch64-none-linux-gnu, x86_64-pc-linux-gnu
and no issues.
Ok for master?
Thanks,
Tamar
gcc/ChangeLog:
PR middle-end/106519
* tree-ssa-phiopt.cc (tree_ssa_phiopt_worker): Check final phi edge for
diamond shapes.
gcc/testsuite/ChangeLog:
PR middle-end/106519
* gcc.dg/pr106519.c: New test.
--- inline copy of patch --
diff --git a/gcc/testsuite/gcc.dg/pr106519.c b/gcc/testsuite/gcc.dg/pr106519.c
new file mode 100644
index
0000000000000000000000000000000000000000..3d4662d8a02c6501560abb71ac53320f093620d8
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr106519.c
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+
+int bytestart, bytemem_0_0, modlookup_l_p;
+
+void
+modlookup_l() {
+ long j;
+ while (modlookup_l_p)
+ while (bytestart && j && bytemem_0_0)
+ j = j + 1;
+}
diff --git a/gcc/tree-ssa-phiopt.cc b/gcc/tree-ssa-phiopt.cc
index
a8e55e040649e17f83a2fc3340e368cf9c4c5e70..1c4942b5b5c18732a8b18789c04e2685437404dd
100644
--- a/gcc/tree-ssa-phiopt.cc
+++ b/gcc/tree-ssa-phiopt.cc
@@ -268,7 +268,8 @@ tree_ssa_phiopt_worker (bool do_store_elim, bool
do_hoist_loads, bool early_p)
continue;
}
else if (EDGE_SUCC (bb1, 0)->dest == EDGE_SUCC (bb2, 0)->dest
- && !empty_block_p (bb1))
+ && !empty_block_p (bb1)
+ && single_succ_p (bb1) && single_succ_p (bb2))
diamond_p = true;
else
continue;
@@ -311,6 +312,12 @@ tree_ssa_phiopt_worker (bool do_store_elim, bool
do_hoist_loads, bool early_p)
for (gsi = gsi_start (phis); !gsi_end_p (gsi); gsi_next (&gsi))
{
phi = as_a <gphi *> (gsi_stmt (gsi));
+
+ /* A diamond must continue to the same destination node,
otherwise
+ by definition it's not a diamond. */
+ if (diamond_p && e1->dest != e2->dest)
+ continue;
+
arg0 = gimple_phi_arg_def (phi, e1->dest_idx);
arg1 = gimple_phi_arg_def (phi, e2->dest_idx);
if (value_replacement (bb, bb1, e1, e2, phi, arg0, arg1) == 2)
@@ -329,12 +336,15 @@ tree_ssa_phiopt_worker (bool do_store_elim, bool
do_hoist_loads, bool early_p)
if (!phi)
continue;
- arg0 = gimple_phi_arg_def (phi, e1->dest_idx);
- arg1 = gimple_phi_arg_def (phi, e2->dest_idx);
+ /* A diamond must continue to the same destination node, otherwise
+ by definition it's not a diamond. */
+ if (diamond_p && e1->dest != e2->dest)
+ continue;
/* Something is wrong if we cannot find the arguments in the PHI
node. */
- gcc_assert (arg0 != NULL_TREE && arg1 != NULL_TREE);
+ arg0 = gimple_phi_arg_def (phi, e1->dest_idx);
+ arg1 = gimple_phi_arg_def (phi, e2->dest_idx);
gphi *newphi;
if (single_pred_p (bb1)
--
diff --git a/gcc/testsuite/gcc.dg/pr106519.c b/gcc/testsuite/gcc.dg/pr106519.c
new file mode 100644
index
0000000000000000000000000000000000000000..3d4662d8a02c6501560abb71ac53320f093620d8
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr106519.c
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+
+int bytestart, bytemem_0_0, modlookup_l_p;
+
+void
+modlookup_l() {
+ long j;
+ while (modlookup_l_p)
+ while (bytestart && j && bytemem_0_0)
+ j = j + 1;
+}
diff --git a/gcc/tree-ssa-phiopt.cc b/gcc/tree-ssa-phiopt.cc
index
a8e55e040649e17f83a2fc3340e368cf9c4c5e70..1c4942b5b5c18732a8b18789c04e2685437404dd
100644
--- a/gcc/tree-ssa-phiopt.cc
+++ b/gcc/tree-ssa-phiopt.cc
@@ -268,7 +268,8 @@ tree_ssa_phiopt_worker (bool do_store_elim, bool
do_hoist_loads, bool early_p)
continue;
}
else if (EDGE_SUCC (bb1, 0)->dest == EDGE_SUCC (bb2, 0)->dest
- && !empty_block_p (bb1))
+ && !empty_block_p (bb1)
+ && single_succ_p (bb1) && single_succ_p (bb2))
diamond_p = true;
else
continue;
@@ -311,6 +312,12 @@ tree_ssa_phiopt_worker (bool do_store_elim, bool
do_hoist_loads, bool early_p)
for (gsi = gsi_start (phis); !gsi_end_p (gsi); gsi_next (&gsi))
{
phi = as_a <gphi *> (gsi_stmt (gsi));
+
+ /* A diamond must continue to the same destination node,
otherwise
+ by definition it's not a diamond. */
+ if (diamond_p && e1->dest != e2->dest)
+ continue;
+
arg0 = gimple_phi_arg_def (phi, e1->dest_idx);
arg1 = gimple_phi_arg_def (phi, e2->dest_idx);
if (value_replacement (bb, bb1, e1, e2, phi, arg0, arg1) == 2)
@@ -329,12 +336,15 @@ tree_ssa_phiopt_worker (bool do_store_elim, bool
do_hoist_loads, bool early_p)
if (!phi)
continue;
- arg0 = gimple_phi_arg_def (phi, e1->dest_idx);
- arg1 = gimple_phi_arg_def (phi, e2->dest_idx);
+ /* A diamond must continue to the same destination node, otherwise
+ by definition it's not a diamond. */
+ if (diamond_p && e1->dest != e2->dest)
+ continue;
/* Something is wrong if we cannot find the arguments in the PHI
node. */
- gcc_assert (arg0 != NULL_TREE && arg1 != NULL_TREE);
+ arg0 = gimple_phi_arg_def (phi, e1->dest_idx);
+ arg1 = gimple_phi_arg_def (phi, e2->dest_idx);
gphi *newphi;
if (single_pred_p (bb1)
