do not pad return after a fall-through Jmp

[r19330]

diff --git a/ir/be/ia32/ia32_optimize.c b/ir/be/ia32/ia32_optimize.c
index 0b4a602..1510522 100644 (file)
--- a/ir/be/ia32/ia32_optimize.c
+++ b/ir/be/ia32/ia32_optimize.c
@@ -310,6 +310,20 @@ static void peephole_ia32_Return(ir_node *node) {
 
        block = get_nodes_block(node);
 
+       if (get_Block_n_cfgpreds(block) == 1) {
+               ir_node *pred = get_Block_cfgpred(block, 0);
+
+               if (is_Jmp(pred)) {
+                       /* The block of the return has only one predecessor,
+                          which jumps directly to this block.
+                          This jump will be encoded as a fall through, so we
+                          ignore it here.
+                          However, the predecessor might be empty, so it must be
+                          ensured that empty blocks are gone away ... */
+                       return;
+               }
+       }
+
        /* check if this return is the first on the block */
        sched_foreach_reverse_from(node, irn) {
                switch (be_get_irn_opcode(irn)) {