From 6eb99d8abbd976c74d7d6ea67b8710d047fd3348 Mon Sep 17 00:00:00 2001 From: rguenth Date: Mon, 2 Apr 2012 15:13:45 +0000 Subject: [PATCH] 2012-04-02 Richard Guenther PR tree-optimization/52756 * tree-ssa-threadupdate.c (def_split_header_continue_p): New function. (thread_through_loop_header): After threading through the loop latch remove the split part from the loop and clear further threading opportunities that would create a multiple entry loop. * gcc.dg/torture/pr52756.c: New testcase. git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@186085 138bc75d-0d04-0410-961f-82ee72b054a4 --- gcc/ChangeLog | 8 ++++++ gcc/testsuite/ChangeLog | 5 ++++ gcc/testsuite/gcc.dg/torture/pr52756.c | 9 +++++++ gcc/tree-ssa-threadupdate.c | 46 ++++++++++++++++++++++++++++++++++ 4 files changed, 68 insertions(+) create mode 100644 gcc/testsuite/gcc.dg/torture/pr52756.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index a020c70..2d4fb1d 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,5 +1,13 @@ 2012-04-02 Richard Guenther + PR tree-optimization/52756 + * tree-ssa-threadupdate.c (def_split_header_continue_p): New function. + (thread_through_loop_header): After threading through the loop latch + remove the split part from the loop and clear further threading + opportunities that would create a multiple entry loop. + +2012-04-02 Richard Guenther + PR rtl-optimization/52800 * cprop.c (execute_rtl_cprop): Call cleanup_cfg with CLEANUP_CFG_CHANGED. diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 2d95e0e..a10bea7 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,5 +1,10 @@ 2012-04-02 Richard Guenther + PR tree-optimization/52756 + * gcc.dg/torture/pr52756.c: New testcase. + +2012-04-02 Richard Guenther + PR middle-end/52803 * gcc.dg/pr52803.c: New testcase. diff --git a/gcc/testsuite/gcc.dg/torture/pr52756.c b/gcc/testsuite/gcc.dg/torture/pr52756.c new file mode 100644 index 0000000..175b414 --- /dev/null +++ b/gcc/testsuite/gcc.dg/torture/pr52756.c @@ -0,0 +1,9 @@ +/* { dg-do compile } */ + +void Env_FetchObj0AttrOffset (unsigned int NumFields, int *Status) +{ + int Found = 0; + if (NumFields) + while ((*Status == 0) && NumFields-- > 0 && Found == 0) + Found = 1; +} diff --git a/gcc/tree-ssa-threadupdate.c b/gcc/tree-ssa-threadupdate.c index 4532886..000bd3f 100644 --- a/gcc/tree-ssa-threadupdate.c +++ b/gcc/tree-ssa-threadupdate.c @@ -826,6 +826,17 @@ determine_bb_domination_status (struct loop *loop, basic_block bb) return (bb_reachable ? DOMST_DOMINATING : DOMST_LOOP_BROKEN); } +/* Return true if BB is part of the new pre-header that is created + when threading the latch to DATA. */ + +static bool +def_split_header_continue_p (const_basic_block bb, const void *data) +{ + const_basic_block new_header = (const_basic_block) data; + return (bb->loop_father == new_header->loop_father + && bb != new_header); +} + /* Thread jumps through the header of LOOP. Returns true if cfg changes. If MAY_PEEL_LOOP_HEADERS is false, we avoid threading from entry edges to the inside of the loop. */ @@ -990,11 +1001,46 @@ thread_through_loop_header (struct loop *loop, bool may_peel_loop_headers) if (latch->aux) { + basic_block *bblocks; + unsigned nblocks, i; + /* First handle the case latch edge is redirected. */ loop->latch = thread_single_edge (latch); gcc_assert (single_succ (loop->latch) == tgt_bb); loop->header = tgt_bb; + /* Remove the new pre-header blocks from our loop. */ + bblocks = XCNEWVEC (basic_block, loop->num_nodes); + nblocks = dfs_enumerate_from (header, 0, def_split_header_continue_p, + bblocks, loop->num_nodes, tgt_bb); + for (i = 0; i < nblocks; i++) + { + remove_bb_from_loops (bblocks[i]); + add_bb_to_loop (bblocks[i], loop_outer (loop)); + } + free (bblocks); + + /* Cancel remaining threading requests that would make the + loop a multiple entry loop. */ + FOR_EACH_EDGE (e, ei, header->preds) + { + edge e2; + if (e->aux == NULL) + continue; + + if (THREAD_TARGET2 (e)) + e2 = THREAD_TARGET2 (e); + else + e2 = THREAD_TARGET (e); + + if (e->src->loop_father != e2->dest->loop_father + && e2->dest != loop->header) + { + free (e->aux); + e->aux = NULL; + } + } + /* Thread the remaining edges through the former header. */ thread_block (header, false); } -- 2.7.4