diff options
Diffstat (limited to 'gcc/loop-unroll.c')
| -rw-r--r-- | gcc/loop-unroll.c | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/gcc/loop-unroll.c b/gcc/loop-unroll.c index 7d230fb6f3a..2f6f3ba2ad9 100644 --- a/gcc/loop-unroll.c +++ b/gcc/loop-unroll.c @@ -899,13 +899,18 @@ decide_unroll_runtime_iterations (struct loop *loop, int flags) loop->lpt_decision.times); } -/* Splits edge E and inserts INSNS on it. */ +/* Splits edge E and inserts the sequence of instructions INSNS on it, and + returns the newly created block. If INSNS is NULL_RTX, nothing is changed + and NULL is returned instead. */ basic_block split_edge_and_insert (edge e, rtx insns) { - basic_block bb = split_edge (e); - gcc_assert (insns != NULL_RTX); + basic_block bb; + + if (!insns) + return NULL; + bb = split_edge (e); emit_insn_after (insns, BB_END (bb)); bb->flags |= BB_SUPERBLOCK; return bb; @@ -1069,6 +1074,10 @@ unroll_loop_runtime_iterations (struct loops *loops, struct loop *loop) block_label (preheader), p, NULL_RTX); + /* We rely on the fact that the compare and jump cannot be optimized out, + and hence the cfg we create is correct. */ + gcc_assert (branch_code != NULL_RTX); + swtch = split_edge_and_insert (single_pred_edge (swtch), branch_code); set_immediate_dominator (CDI_DOMINATORS, preheader, swtch); single_pred_edge (swtch)->probability = REG_BR_PROB_BASE - p; @@ -1086,6 +1095,7 @@ unroll_loop_runtime_iterations (struct loops *loops, struct loop *loop) branch_code = compare_and_jump_seq (copy_rtx (niter), const0_rtx, EQ, block_label (preheader), p, NULL_RTX); + gcc_assert (branch_code != NULL_RTX); swtch = split_edge_and_insert (single_succ_edge (swtch), branch_code); set_immediate_dominator (CDI_DOMINATORS, preheader, swtch); |