From fba7c56424a5ffc8e098c7b4638c19f2545ef2be Mon Sep 17 00:00:00 2001 From: Richard Biener Date: Fri, 28 Feb 2014 13:14:23 +0000 Subject: [PATCH] re PR tree-optimization/60280 (gcc.target/arm/ivopts.c and gcc.target/arm/ivopts-2.c failed caused by preserving loop structure.) 2014-02-28 Richard Biener PR target/60280 * tree-cfgcleanup.c (tree_forwarder_block_p): Restrict previous fix and only allow to remove trivial pre-headers and latches. Also honor LOOPS_MAY_HAVE_MULTIPLE_LATCHES. (remove_forwarder_block): Properly update the latch of a loop. From-SVN: r208222 --- gcc/ChangeLog | 9 +++++++++ gcc/tree-cfgcleanup.c | 29 +++++++++++++++++++++-------- 2 files changed, 30 insertions(+), 8 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index f90cc91371b..3d33ce004e9 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,12 @@ +2014-02-28 Richard Biener + + PR target/60280 + * tree-cfgcleanup.c (tree_forwarder_block_p): Restrict + previous fix and only allow to remove trivial pre-headers + and latches. Also honor LOOPS_MAY_HAVE_MULTIPLE_LATCHES. + (remove_forwarder_block): Properly update the latch of + a loop. + 2014-02-28 Alexandre Oliva PR debug/59992 diff --git a/gcc/tree-cfgcleanup.c b/gcc/tree-cfgcleanup.c index b5c384b902c..926d3000dc5 100644 --- a/gcc/tree-cfgcleanup.c +++ b/gcc/tree-cfgcleanup.c @@ -316,13 +316,22 @@ tree_forwarder_block_p (basic_block bb, bool phi_wanted) /* Protect loop preheaders and latches if requested. */ if (dest->loop_father->header == dest) { - if (loops_state_satisfies_p (LOOPS_HAVE_PREHEADERS) - && bb->loop_father->header != dest) - return false; - - if (loops_state_satisfies_p (LOOPS_HAVE_SIMPLE_LATCHES) - && bb->loop_father->header == dest) - return false; + if (bb->loop_father == dest->loop_father) + { + if (loops_state_satisfies_p (LOOPS_HAVE_SIMPLE_LATCHES)) + return false; + /* If bb doesn't have a single predecessor we'd make this + loop have multiple latches. Don't do that if that + would in turn require disambiguating them. */ + return (single_pred_p (bb) + || loops_state_satisfies_p + (LOOPS_MAY_HAVE_MULTIPLE_LATCHES)); + } + else if (bb->loop_father == loop_outer (dest->loop_father)) + return !loops_state_satisfies_p (LOOPS_HAVE_PREHEADERS); + /* Always preserve other edges into loop headers that are + not simple latches or preheaders. */ + return false; } } @@ -417,6 +426,10 @@ remove_forwarder_block (basic_block bb) can_move_debug_stmts = MAY_HAVE_DEBUG_STMTS && single_pred_p (dest); + basic_block pred = NULL; + if (single_pred_p (bb)) + pred = single_pred (bb); + /* Redirect the edges. */ for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); ) { @@ -510,7 +523,7 @@ remove_forwarder_block (basic_block bb) /* Adjust latch infomation of BB's parent loop as otherwise the cfg hook has a hard time not to kill the loop. */ if (current_loops && bb->loop_father->latch == bb) - bb->loop_father->latch = dest; + bb->loop_father->latch = pred; /* And kill the forwarder block. */ delete_basic_block (bb); -- 2.30.2