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Diffstat (limited to 'gcc/tree-ssa-dse.c')
| -rw-r--r-- | gcc/tree-ssa-dse.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/gcc/tree-ssa-dse.c b/gcc/tree-ssa-dse.c index 2e6f8ff..65dcb12 100644 --- a/gcc/tree-ssa-dse.c +++ b/gcc/tree-ssa-dse.c @@ -129,6 +129,8 @@ valid_ao_ref_for_dse (ao_ref *ref) { return (ao_ref_base (ref) && ref->max_size != -1 + && ref->size != 0 + && ref->max_size == ref->size && (ref->offset % BITS_PER_UNIT) == 0 && (ref->size % BITS_PER_UNIT) == 0 && (ref->size != -1)); @@ -221,7 +223,6 @@ compute_trims (ao_ref *ref, sbitmap live, int *trim_head, int *trim_tail) the REF to compute the trims. */ /* Now identify how much, if any of the tail we can chop off. */ - *trim_tail = 0; int last_orig = (ref->size / BITS_PER_UNIT) - 1; int last_live = bitmap_last_set_bit (live); *trim_tail = (last_orig - last_live) & ~0x1; @@ -700,6 +701,16 @@ dse_dom_walker::dse_optimize_stmt (gimple_stmt_iterator *gsi) case BUILT_IN_MEMMOVE: case BUILT_IN_MEMSET: { + /* Occasionally calls with an explicit length of zero + show up in the IL. It's pointless to do analysis + on them, they're trivially dead. */ + tree size = gimple_call_arg (stmt, 2); + if (integer_zerop (size)) + { + delete_dead_call (gsi); + return; + } + gimple *use_stmt; enum dse_store_status store_status; m_byte_tracking_enabled |