From 72b8d451f1b0c3bef4b3afc688ada5d5175d97d0 Mon Sep 17 00:00:00 2001 From: Zdenek Dvorak Date: Sat, 8 Mar 2003 10:47:28 +0100 Subject: [PATCH] gcse.c (bypass_block, [...]): Do not create irreducible loops. * gcse.c (bypass_block, bypass_conditional_jumps): Do not create irreducible loops. * loop-unroll.c (unroll_loop_runtime_iterations): Update irreducible loops info correctly. From-SVN: r63980 --- gcc/ChangeLog | 8 ++++++++ gcc/gcse.c | 17 +++++++++++++++++ gcc/loop-unroll.c | 6 ++++-- 3 files changed, 29 insertions(+), 2 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 663b3eb5430..e3919a9ef84 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,11 @@ +2003-03-08 Zdenek Dvorak + + * gcse.c (bypass_block, bypass_conditional_jumps): Do not create + irreducible loops. + + * loop-unroll.c (unroll_loop_runtime_iterations): Update irreducible + loops info correctly. + 2003-03-08 Eric Botcazou PR middle-end/7796 diff --git a/gcc/gcse.c b/gcc/gcse.c index f5bb66d0053..f0e588ecd49 100644 --- a/gcc/gcse.c +++ b/gcc/gcse.c @@ -4759,6 +4759,7 @@ bypass_block (bb, setcc, jump) rtx insn, note; edge e, enext; int i, change; + int may_be_loop_header; insn = (setcc != NULL) ? setcc : jump; @@ -4769,6 +4770,14 @@ bypass_block (bb, setcc, jump) if (note) find_used_regs (&XEXP (note, 0), NULL); + may_be_loop_header = false; + for (e = bb->pred; e; e = e->pred_next) + if (e->flags & EDGE_DFS_BACK) + { + may_be_loop_header = true; + break; + } + change = 0; for (e = bb->pred; e; e = enext) { @@ -4780,6 +4789,13 @@ bypass_block (bb, setcc, jump) if (e->src->index >= bypass_last_basic_block) continue; + /* The irreducible loops created by redirecting of edges entering the + loop from outside would decrease effectivity of some of the following + optimalizations, so prevent this. */ + if (may_be_loop_header + && !(e->flags & EDGE_DFS_BACK)) + continue; + for (i = 0; i < reg_use_count; i++) { struct reg_use *reg_used = ®_use_table[i]; @@ -4866,6 +4882,7 @@ bypass_conditional_jumps () return 0; bypass_last_basic_block = last_basic_block; + mark_dfs_back_edges (); changed = 0; FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR->next_bb->next_bb, diff --git a/gcc/loop-unroll.c b/gcc/loop-unroll.c index 55899a97c49..e39bdbcbffb 100644 --- a/gcc/loop-unroll.c +++ b/gcc/loop-unroll.c @@ -895,7 +895,8 @@ unroll_loop_runtime_iterations (loops, loop) swtch = loop_split_edge_with (swtch->pred, branch_code, loops); set_immediate_dominator (loops->cfg.dom, preheader, swtch); swtch->succ->probability = REG_BR_PROB_BASE - p; - e = make_edge (swtch, preheader, 0); + e = make_edge (swtch, preheader, + swtch->succ->flags & EDGE_IRREDUCIBLE_LOOP); e->probability = p; } } @@ -925,7 +926,8 @@ unroll_loop_runtime_iterations (loops, loop) swtch = loop_split_edge_with (swtch->succ, branch_code, loops); set_immediate_dominator (loops->cfg.dom, preheader, swtch); swtch->succ->probability = REG_BR_PROB_BASE - p; - e = make_edge (swtch, preheader, 0); + e = make_edge (swtch, preheader, + swtch->succ->flags & EDGE_IRREDUCIBLE_LOOP); e->probability = p; } -- 2.30.2