phi = allocate_phi_node (capacity);
- /* We do not have to clear a part of the PHI node that stores PHI
- arguments, which is safe because we tell the garbage collector to
- scan up to num_args elements in the array of PHI arguments. In
- other words, the garbage collector will not follow garbage
- pointers in the unused portion of the array. */
- memset (phi, 0, sizeof (struct tree_phi_node) - sizeof (struct phi_arg_d));
+ /* We need to clear the entire PHI node, including the argument
+ portion, because we represent a "missing PHI argument" by placing
+ NULL_TREE in PHI_ARG_DEF. */
+ memset (phi, 0, (sizeof (struct tree_phi_node) - sizeof (struct phi_arg_d)
+ + sizeof (struct phi_arg_d) * len));
TREE_SET_CODE (phi, PHI_NODE);
+ PHI_NUM_ARGS (phi) = len;
PHI_ARG_CAPACITY (phi) = capacity;
TREE_TYPE (phi) = TREE_TYPE (var);
if (TREE_CODE (var) == SSA_NAME)
int old_size;
tree new_phi;
- gcc_assert (len >= PHI_ARG_CAPACITY (*phi));
+ gcc_assert (len > PHI_ARG_CAPACITY (*phi));
/* The garbage collector will not look at the PHI node beyond the
first PHI_NUM_ARGS elements. Therefore, all we have to copy is a
release_phi_node (old_phi);
}
+
+ /* We represent a "missing PHI argument" by placing NULL_TREE in
+ the corresponding slot. If PHI arguments were added
+ immediately after an edge is created, this zeroing would not
+ be necessary, but unfortunately this is not the case. For
+ example, the loop optimizer duplicates several basic blocks,
+ redirects edges, and then fixes up PHI arguments later in
+ batch. */
+ SET_PHI_ARG_DEF (*loc, len - 1, NULL_TREE);
+
+ PHI_NUM_ARGS (*loc)++;
}
}
add_phi_arg (tree *phi, tree def, edge e)
{
basic_block bb = e->dest;
- int i = PHI_NUM_ARGS (*phi);
gcc_assert (bb == bb_for_stmt (*phi));
/* We resize PHI nodes upon edge creation. We should always have
enough room at this point. */
- gcc_assert (PHI_NUM_ARGS (*phi) < PHI_ARG_CAPACITY (*phi));
+ gcc_assert (PHI_NUM_ARGS (*phi) <= PHI_ARG_CAPACITY (*phi));
+
+ /* We resize PHI nodes upon edge creation. We should always have
+ enough room at this point. */
+ gcc_assert (e->dest_idx < (unsigned int) PHI_NUM_ARGS (*phi));
/* Copy propagation needs to know what object occur in abnormal
PHI nodes. This is a convenient place to record such information. */
SSA_NAME_OCCURS_IN_ABNORMAL_PHI (PHI_RESULT (*phi)) = 1;
}
- SET_PHI_ARG_DEF (*phi, i, def);
- PHI_ARG_EDGE (*phi, i) = e;
- PHI_ARG_NONZERO (*phi, i) = false;
- PHI_NUM_ARGS (*phi)++;
+ SET_PHI_ARG_DEF (*phi, e->dest_idx, def);
+ PHI_ARG_NONZERO (*phi, e->dest_idx) = false;
}
/* Remove the Ith argument from PHI's argument list. This routine assumes
if (i != num_elem - 1)
{
SET_PHI_ARG_DEF (phi, i, PHI_ARG_DEF (phi, num_elem - 1));
- PHI_ARG_EDGE (phi, i) = PHI_ARG_EDGE (phi, num_elem - 1);
PHI_ARG_NONZERO (phi, i) = PHI_ARG_NONZERO (phi, num_elem - 1);
}
/* Shrink the vector and return. Note that we do not have to clear
- PHI_ARG_DEF, PHI_ARG_EDGE, or PHI_ARG_NONZERO because the garbage
- collector will not look at those elements beyond the first
- PHI_NUM_ARGS elements of the array. */
+ PHI_ARG_DEF or PHI_ARG_NONZERO because the garbage collector will
+ not look at those elements beyond the first PHI_NUM_ARGS elements
+ of the array. */
PHI_NUM_ARGS (phi)--;
}