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-rw-r--r--gcc/function.c19
1 files changed, 16 insertions, 3 deletions
diff --git a/gcc/function.c b/gcc/function.c
index a081b270ec0..506ec030745 100644
--- a/gcc/function.c
+++ b/gcc/function.c
@@ -5956,9 +5956,22 @@ thread_prologue_and_epilogue_insns (void)
FOR_EACH_EDGE (e, ei, tmp_bb->preds)
if (single_succ_p (e->src)
&& !bitmap_bit_p (&bb_on_list, e->src->index)
- && can_duplicate_block_p (e->src)
- && bitmap_set_bit (&bb_tail, e->src->index))
- VEC_quick_push (basic_block, vec, e->src);
+ && can_duplicate_block_p (e->src))
+ {
+ edge pe;
+ edge_iterator pei;
+
+ /* If there is predecessor of e->src which doesn't
+ need prologue and the edge is complex,
+ we might not be able to redirect the branch
+ to a copy of e->src. */
+ FOR_EACH_EDGE (pe, pei, e->src->preds)
+ if ((pe->flags & EDGE_COMPLEX) != 0
+ && !bitmap_bit_p (&bb_flags, pe->src->index))
+ break;
+ if (pe == NULL && bitmap_set_bit (&bb_tail, e->src->index))
+ VEC_quick_push (basic_block, vec, e->src);
+ }
}
/* Now walk backwards from every block that is marked as needing