diff options
| -rw-r--r-- | gcc/tree-ssa-copy.c | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/gcc/tree-ssa-copy.c b/gcc/tree-ssa-copy.c index ca9f0cc..e544992 100644 --- a/gcc/tree-ssa-copy.c +++ b/gcc/tree-ssa-copy.c @@ -272,11 +272,16 @@ cprop_into_stmt (tree stmt, varray_type const_and_copies) /* CONST_AND_COPIES is a table which maps an SSA_NAME to the current known value for that SSA_NAME (or NULL if no value is known). - Propagate values from CONST_AND_COPIES into the PHI nodes of the - successors of BB. */ + NONZERO_VARS is the set SSA_NAMES known to have a nonzero value, + even if we don't know their precise value. + + Propagate values from CONST_AND_COPIES and NONZERO_VARS into the PHI + nodes of the successors of BB. */ void -cprop_into_successor_phis (basic_block bb, varray_type const_and_copies) +cprop_into_successor_phis (basic_block bb, + varray_type const_and_copies, + bitmap nonzero_vars) { edge e; @@ -342,6 +347,11 @@ cprop_into_successor_phis (basic_block bb, varray_type const_and_copies) if (TREE_CODE (*orig_p) != SSA_NAME) continue; + /* If the alternative is known to have a nonzero value, record + that fact in the PHI node itself for future use. */ + if (bitmap_bit_p (nonzero_vars, SSA_NAME_VERSION (*orig_p))) + PHI_ARG_NONZERO (phi, i) = true; + /* If we have *ORIG_P in our constant/copy table, then replace ORIG_P with its value in our constant/copy table. */ new = VARRAY_TREE (const_and_copies, SSA_NAME_VERSION (*orig_p)); |