From patchwork Mon Jun 14 13:07:18 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: Avoid doing DCE in substitute_and_fold from VRP (PR tree-optimization/44508) Date: Mon, 14 Jun 2010 03:07:18 -0000 From: Jakub Jelinek X-Patchwork-Id: 55529 Message-Id: <20100614130718.GJ7811@tyan-ft48-01.lab.bos.redhat.com> To: Richard Guenther Cc: gcc-patches@gcc.gnu.org Hi! libgomp.fortran/vla*.f90 fails on s390 on 4.4 branch, because substitute_and_fold DCEs some trivially dead statements after earlier substitutions/folding), which releases the LHS SSA_NAMEs. Those SSA_NAMEs are still referenced from some VRP ranges though and can result in crashes, either still in substitute_and_fold in other folding using VRP, or in subsequent identify_jump_threads call. The problem is just latent on the trunk. Bootstrapped/regtested on x86_64-linux and i686-linux on the trunk and on x86_64-linux, i686-linux and s390-linux so far on 4.4 branch. Jakub 2010-06-14 Jakub Jelinek PR tree-optimization/44508 * tree-ssa-propagate.h (substitute_and_fold): Add DO_DCE argument. * tree-ssa-propagate.c (substitute_and_fold): If !DO_DCE, don't eliminate trivially dead stmts. * tree-vrp.c (vrp_finalize): Pass false as last argument to substitute_and_fold. * tree-ssa-copy.c (fini_copy_prop): Pass true as last argument to substitute_and_fold. * tree-ssa-ccp.c (ccp_finalize): Likewise. * gcc.dg/tree-ssa/pr21086.c: Adjust. 2010-06-14 Jakub Jelinek PR tree-optimization/44508 * tree-ssa-propagate.c (substitute_and_fold): Don't do DCE when called from tree-vrp.c. * gcc.dg/tree-ssa/pr21086.c: Adjust. --- gcc/tree-ssa-propagate.c.jj 2009-04-24 21:41:29.000000000 +0200 +++ gcc/tree-ssa-propagate.c 2010-06-14 09:39:54.000000000 +0200 @@ -1113,8 +1113,12 @@ substitute_and_fold (prop_value_t *prop_ } /* No point propagating into a stmt whose result is not used, - but instead we might be able to remove a trivially dead stmt. */ - if (gimple_get_lhs (stmt) + but instead we might be able to remove a trivially dead stmt. + Don't do this when called from VRP, since the SSA_NAME which + is going to be released could be still referenced in VRP + ranges. */ + if (!use_ranges_p + && gimple_get_lhs (stmt) && TREE_CODE (gimple_get_lhs (stmt)) == SSA_NAME && has_zero_uses (gimple_get_lhs (stmt)) && !stmt_could_throw_p (stmt) --- gcc/testsuite/gcc.dg/tree-ssa/pr21086.c.jj 2010-06-11 11:00:43.000000000 +0200 +++ gcc/testsuite/gcc.dg/tree-ssa/pr21086.c 2010-06-14 13:14:39.354353715 +0200 @@ -1,5 +1,5 @@ /* { dg-do compile } */ -/* { dg-options "-O2 -fdump-tree-vrp1" } */ +/* { dg-options "-O2 -fdump-tree-vrp1 -fdump-tree-dce1" } */ int foo (int *p) @@ -16,8 +16,9 @@ foo (int *p) } /* Target with fno-delete-null-pointer-checks should not fold checks */ -/* { dg-final { scan-tree-dump-times "Folding predicate " 1 "vrp1" { target { ! keeps_null_pointer_checks } } } } */ +/* { dg-final { scan-tree-dump "Folding predicate " "vrp1" { target { ! keeps_null_pointer_checks } } } } */ /* { dg-final { scan-tree-dump-times "Folding predicate " 0 "vrp1" { target { keeps_null_pointer_checks } } } } */ -/* { dg-final { scan-tree-dump-not "b_. =" "vrp1" { target { ! avr-*-* } } } } */ -/* { dg-final { scan-tree-dump "b_. =" "vrp1" { target { avr-*-* } } } } */ +/* { dg-final { scan-tree-dump-not "b_. =" "dce1" { target { ! avr-*-* } } } } */ +/* { dg-final { scan-tree-dump "b_. =" "dce1" { target { avr-*-* } } } } */ /* { dg-final { cleanup-tree-dump "vrp1" } } */ +/* { dg-final { cleanup-tree-dump "dce1" } } */ --- gcc/tree-ssa-propagate.h.jj 2010-06-11 11:06:00.000000000 +0200 +++ gcc/tree-ssa-propagate.h 2010-06-14 10:25:45.161210781 +0200 @@ -120,6 +120,6 @@ bool valid_gimple_call_p (tree); void move_ssa_defining_stmt_for_defs (gimple, gimple); bool update_call_from_tree (gimple_stmt_iterator *, tree); bool stmt_makes_single_store (gimple); -bool substitute_and_fold (prop_value_t *, ssa_prop_fold_stmt_fn); +bool substitute_and_fold (prop_value_t *, ssa_prop_fold_stmt_fn, bool); #endif /* _TREE_SSA_PROPAGATE_H */ --- gcc/tree-ssa-propagate.c.jj 2010-06-11 11:06:00.858283899 +0200 +++ gcc/tree-ssa-propagate.c 2010-06-14 10:26:30.399304971 +0200 @@ -964,10 +964,13 @@ replace_phi_args_in (gimple phi, prop_va If FOLD_FN is non-NULL the function will be invoked on all statements before propagating values for pass specific simplification. + DO_DCE is true if trivially dead stmts can be removed. + Return TRUE when something changed. */ bool -substitute_and_fold (prop_value_t *prop_value, ssa_prop_fold_stmt_fn fold_fn) +substitute_and_fold (prop_value_t *prop_value, ssa_prop_fold_stmt_fn fold_fn, + bool do_dce) { basic_block bb; bool something_changed = false; @@ -1012,8 +1015,12 @@ substitute_and_fold (prop_value_t *prop_ continue; /* No point propagating into a stmt whose result is not used, - but instead we might be able to remove a trivially dead stmt. */ - if (gimple_get_lhs (stmt) + but instead we might be able to remove a trivially dead stmt. + Don't do this when called from VRP, since the SSA_NAME which + is going to be released could be still referenced in VRP + ranges. */ + if (do_dce + && gimple_get_lhs (stmt) && TREE_CODE (gimple_get_lhs (stmt)) == SSA_NAME && has_zero_uses (gimple_get_lhs (stmt)) && !stmt_could_throw_p (stmt) --- gcc/tree-ssa-copy.c.jj 2010-06-11 11:06:00.000000000 +0200 +++ gcc/tree-ssa-copy.c 2010-06-14 10:27:32.306210726 +0200 @@ -854,7 +854,7 @@ fini_copy_prop (void) duplicate_ssa_name_ptr_info (tmp[i].value, SSA_NAME_PTR_INFO (var)); } - substitute_and_fold (tmp, NULL); + substitute_and_fold (tmp, NULL, true); free (cached_last_copy_of); free (copy_of); --- gcc/tree-ssa-ccp.c.jj 2010-06-11 11:06:00.000000000 +0200 +++ gcc/tree-ssa-ccp.c 2010-06-14 10:27:17.336210560 +0200 @@ -682,7 +682,7 @@ ccp_finalize (void) do_dbg_cnt (); /* Perform substitutions based on the known constant values. */ - something_changed = substitute_and_fold (const_val, ccp_fold_stmt); + something_changed = substitute_and_fold (const_val, ccp_fold_stmt, true); free (const_val); const_val = NULL; --- gcc/tree-vrp.c.jj 2010-06-11 11:06:00.000000000 +0200 +++ gcc/tree-vrp.c 2010-06-14 10:27:00.002354677 +0200 @@ -7343,7 +7343,7 @@ vrp_finalize (void) single_val_range = NULL; } - substitute_and_fold (single_val_range, vrp_fold_stmt); + substitute_and_fold (single_val_range, vrp_fold_stmt, false); if (warn_array_bounds) check_all_array_refs (); --- gcc/testsuite/gcc.dg/tree-ssa/pr21086.c.jj 2010-06-11 11:00:43.000000000 +0200 +++ gcc/testsuite/gcc.dg/tree-ssa/pr21086.c 2010-06-14 13:14:39.354353715 +0200 @@ -1,5 +1,5 @@ /* { dg-do compile } */ -/* { dg-options "-O2 -fdump-tree-vrp1" } */ +/* { dg-options "-O2 -fdump-tree-vrp1 -fdump-tree-dce1" } */ int foo (int *p) @@ -16,8 +16,9 @@ foo (int *p) } /* Target with fno-delete-null-pointer-checks should not fold checks */ -/* { dg-final { scan-tree-dump-times "Folding predicate " 1 "vrp1" { target { ! keeps_null_pointer_checks } } } } */ +/* { dg-final { scan-tree-dump "Folding predicate " "vrp1" { target { ! keeps_null_pointer_checks } } } } */ /* { dg-final { scan-tree-dump-times "Folding predicate " 0 "vrp1" { target { keeps_null_pointer_checks } } } } */ -/* { dg-final { scan-tree-dump-not "b_. =" "vrp1" { target { ! avr-*-* } } } } */ -/* { dg-final { scan-tree-dump "b_. =" "vrp1" { target { avr-*-* } } } } */ +/* { dg-final { scan-tree-dump-not "b_. =" "dce1" { target { ! avr-*-* } } } } */ +/* { dg-final { scan-tree-dump "b_. =" "dce1" { target { avr-*-* } } } } */ /* { dg-final { cleanup-tree-dump "vrp1" } } */ +/* { dg-final { cleanup-tree-dump "dce1" } } */