From 7a2eceff8f1f275c2cda0ac25db354697bf33f7d Mon Sep 17 00:00:00 2001 From: Jakub Jelinek Date: Fri, 25 Jun 2010 14:10:42 +0200 Subject: [PATCH] re PR middle-end/43866 (wrong code with -fbounds-check -funswitch-loops) PR middle-end/43866 * tree-ssa-loop-unswitch.c (tree_may_unswitch_on): If stmt is always true or always false, return NULL_TREE. (tree_unswitch_single_loop): Optimize conditions even when reaching max-unswitch-level parameter. If num > 0, optimize first all conditions using entry checks, then do still reachable block discovery and consider only conditions in still reachable basic blocks in the loop. * gfortran.dg/pr43866.f90: New test. From-SVN: r161375 --- gcc/ChangeLog | 8 ++ gcc/testsuite/ChangeLog | 3 + gcc/testsuite/gfortran.dg/pr43866.f90 | 44 +++++++++ gcc/tree-ssa-loop-unswitch.c | 130 ++++++++++++++++++++++---- 4 files changed, 165 insertions(+), 20 deletions(-) create mode 100644 gcc/testsuite/gfortran.dg/pr43866.f90 diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 64c82e2b1e5..5a63014727d 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,5 +1,13 @@ 2010-06-25 Jakub Jelinek + PR middle-end/43866 + * tree-ssa-loop-unswitch.c (tree_may_unswitch_on): If stmt is always + true or always false, return NULL_TREE. + (tree_unswitch_single_loop): Optimize conditions even when reaching + max-unswitch-level parameter. If num > 0, optimize first all conditions + using entry checks, then do still reachable block discovery and consider + only conditions in still reachable basic blocks in the loop. + PR tree-optimization/44539 * tree-cfgcleanup.c (fixup_noreturn_call): Call update_stmt even when the call doesn't have LHS, but has VDEF. diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 55b801910a9..7f20137df96 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,5 +1,8 @@ 2010-06-25 Jakub Jelinek + PR middle-end/43866 + * gfortran.dg/pr43866.f90: New test. + PR tree-optimization/44539 * gcc.dg/pr44539.c: New test. diff --git a/gcc/testsuite/gfortran.dg/pr43866.f90 b/gcc/testsuite/gfortran.dg/pr43866.f90 new file mode 100644 index 00000000000..abfdaa1557f --- /dev/null +++ b/gcc/testsuite/gfortran.dg/pr43866.f90 @@ -0,0 +1,44 @@ +! PR middle-end/43866 +! { dg-do run } +! { dg-options "-funswitch-loops -fbounds-check" } + +MODULE PR43866 + IMPLICIT NONE + TYPE TT + REAL(KIND=4), DIMENSION(:,:), POINTER :: A + REAL(KIND=8), DIMENSION(:,:), POINTER :: B + END TYPE +CONTAINS + SUBROUTINE FOO(M,X,Y,T) + TYPE(TT), POINTER :: M + INTEGER, INTENT(IN) :: Y, X + INTEGER :: C, D + LOGICAL :: T + REAL(KIND = 4), DIMENSION(:,:), POINTER :: P + REAL(KIND = 8), DIMENSION(:,:), POINTER :: Q + + Q => M%B + P => M%A + DO C=1,X + DO D=C+1,Y + IF (T) THEN + P(D,C)=P(C,D) + ELSE + Q(D,C)=Q(C,D) + ENDIF + ENDDO + ENDDO + END SUBROUTINE FOO +END MODULE PR43866 + + USE PR43866 + TYPE(TT), POINTER :: Q + INTEGER, PARAMETER :: N=17 + ALLOCATE (Q) + NULLIFY (Q%A) + ALLOCATE (Q%B(N,N)) + Q%B=0 + CALL FOO (Q,N,N,.FALSE.) +END + +! { dg-final { cleanup-modules "pr43866" } } diff --git a/gcc/tree-ssa-loop-unswitch.c b/gcc/tree-ssa-loop-unswitch.c index 6bc40af263c..b6b32dcd99a 100644 --- a/gcc/tree-ssa-loop-unswitch.c +++ b/gcc/tree-ssa-loop-unswitch.c @@ -1,5 +1,5 @@ /* Loop unswitching. - Copyright (C) 2004, 2005, 2007, 2008 Free Software Foundation, Inc. + Copyright (C) 2004, 2005, 2007, 2008, 2010 Free Software Foundation, Inc. This file is part of GCC. @@ -129,6 +129,12 @@ tree_may_unswitch_on (basic_block bb, struct loop *loop) if (!stmt || gimple_code (stmt) != GIMPLE_COND) return NULL_TREE; + /* To keep the things simple, we do not directly remove the conditions, + but just replace tests with 0 != 0 resp. 1 != 0. Prevent the infinite + loop where we would unswitch again on such a condition. */ + if (gimple_cond_true_p (stmt) || gimple_cond_false_p (stmt)) + return NULL_TREE; + /* Condition must be invariant. */ FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_USE) { @@ -142,12 +148,6 @@ tree_may_unswitch_on (basic_block bb, struct loop *loop) cond = build2 (gimple_cond_code (stmt), boolean_type_node, gimple_cond_lhs (stmt), gimple_cond_rhs (stmt)); - /* To keep the things simple, we do not directly remove the conditions, - but just replace tests with 0/1. Prevent the infinite loop where we - would unswitch again on such a condition. */ - if (integer_zerop (cond) || integer_nonzerop (cond)) - return NULL_TREE; - return cond; } @@ -193,21 +193,14 @@ tree_unswitch_single_loop (struct loop *loop, int num) { basic_block *bbs; struct loop *nloop; - unsigned i; + unsigned i, found; tree cond = NULL_TREE; gimple stmt; bool changed = false; - /* Do not unswitch too much. */ - if (num > PARAM_VALUE (PARAM_MAX_UNSWITCH_LEVEL)) - { - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, ";; Not unswitching anymore, hit max level\n"); - return false; - } - i = 0; bbs = get_loop_body (loop); + found = loop->num_nodes; while (1) { @@ -218,8 +211,17 @@ tree_unswitch_single_loop (struct loop *loop, int num) if (i == loop->num_nodes) { - free (bbs); - return changed; + if (dump_file + && num > PARAM_VALUE (PARAM_MAX_UNSWITCH_LEVEL) + && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, ";; Not unswitching anymore, hit max level\n"); + + if (found == loop->num_nodes) + { + free (bbs); + return changed; + } + break; } cond = simplify_using_entry_checks (loop, cond); @@ -236,19 +238,107 @@ tree_unswitch_single_loop (struct loop *loop, int num) gimple_cond_set_condition_from_tree (stmt, boolean_false_node); changed = true; } + /* Do not unswitch too much. */ + else if (num > PARAM_VALUE (PARAM_MAX_UNSWITCH_LEVEL)) + { + i++; + continue; + } + /* In nested tree_unswitch_single_loop first optimize all conditions + using entry checks, then discover still reachable blocks in the + loop and find the condition only among those still reachable bbs. */ + else if (num != 0) + { + if (found == loop->num_nodes) + found = i; + i++; + continue; + } else - break; + { + found = i; + break; + } update_stmt (stmt); i++; } + if (num != 0) + { + basic_block *tos, *worklist; + + /* When called recursively, first do a quick discovery + of reachable bbs after the above changes and only + consider conditions in still reachable bbs. */ + tos = worklist = XNEWVEC (basic_block, loop->num_nodes); + + for (i = 0; i < loop->num_nodes; i++) + bbs[i]->flags &= ~BB_REACHABLE; + + /* Start with marking header. */ + *tos++ = bbs[0]; + bbs[0]->flags |= BB_REACHABLE; + + /* Iterate: find everything reachable from what we've already seen + within the same innermost loop. Don't look through false edges + if condition is always true or true edges if condition is + always false. */ + while (tos != worklist) + { + basic_block b = *--tos; + edge e; + edge_iterator ei; + int flags = 0; + + if (EDGE_COUNT (b->succs) == 2) + { + gimple stmt = last_stmt (b); + if (stmt + && gimple_code (stmt) == GIMPLE_COND) + { + if (gimple_cond_true_p (stmt)) + flags = EDGE_FALSE_VALUE; + else if (gimple_cond_false_p (stmt)) + flags = EDGE_TRUE_VALUE; + } + } + + FOR_EACH_EDGE (e, ei, b->succs) + { + basic_block dest = e->dest; + + if (dest->loop_father == loop + && !(dest->flags & BB_REACHABLE) + && !(e->flags & flags)) + { + *tos++ = dest; + dest->flags |= BB_REACHABLE; + } + } + } + + free (worklist); + + /* Find a bb to unswitch on. */ + for (; found < loop->num_nodes; found++) + if ((bbs[found]->flags & BB_REACHABLE) + && (cond = tree_may_unswitch_on (bbs[found], loop))) + break; + + if (found == loop->num_nodes) + { + free (bbs); + return changed; + } + } + if (dump_file && (dump_flags & TDF_DETAILS)) fprintf (dump_file, ";; Unswitching loop\n"); initialize_original_copy_tables (); /* Unswitch the loop on this condition. */ - nloop = tree_unswitch_loop (loop, bbs[i], cond); + nloop = tree_unswitch_loop (loop, bbs[found], cond); if (!nloop) { free_original_copy_tables ();