From cb2d412c3e3fc246c1e52809ff13d587388f8b5f Mon Sep 17 00:00:00 2001 From: Richard Guenther Date: Fri, 23 Nov 2007 09:49:29 +0000 Subject: [PATCH] tree-ssa-copy.c (may_propagate_copy): Remove redundant checks. 2007-11-23 Richard Guenther * tree-ssa-copy.c (may_propagate_copy): Remove redundant checks. (merge_alias_info): Do verification only if checking is enabled. Merge flow-sensitive alias information in simple cases. * tree-ssa-operands.c (get_addr_dereference_operands): Also complain about missing NMTs. * gcc.dg/tree-ssa/alias-17.c: New testcase. From-SVN: r130370 --- gcc/testsuite/ChangeLog | 4 ++ gcc/testsuite/gcc.dg/tree-ssa/alias-17.c | 18 ++++++++ gcc/tree-ssa-copy.c | 58 ++++++++++++++---------- gcc/tree-ssa-operands.c | 8 ++-- 4 files changed, 61 insertions(+), 27 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/alias-17.c diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index ca92fa8a9b3..d9aee04b513 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,7 @@ +2007-11-23 Richard Guenther + + * gcc.dg/tree-ssa/alias-17.c: New testcase. + 2007-11-22 Joseph Myers PR c/14050 diff --git a/gcc/testsuite/gcc.dg/tree-ssa/alias-17.c b/gcc/testsuite/gcc.dg/tree-ssa/alias-17.c new file mode 100644 index 00000000000..48e72ffee2f --- /dev/null +++ b/gcc/testsuite/gcc.dg/tree-ssa/alias-17.c @@ -0,0 +1,18 @@ +/* { dg-do compile } */ +/* { dg-options "-O -fno-early-inlining -fdump-tree-ccp2" } */ + +int *p; +int inline bar(void) { return 0; } +int foo(int x) +{ + int i; + int *q; + if (bar()) + q = &i; + else + q = p; + return *q + *p; +} + +/* { dg-final { scan-tree-dump-not "NOTE: no flow-sensitive alias info for" "ccp2" } } */ +/* { dg-final { cleanup-tree-dump "ccp2" } } */ diff --git a/gcc/tree-ssa-copy.c b/gcc/tree-ssa-copy.c index 9f58087cfac..ae4f50c2feb 100644 --- a/gcc/tree-ssa-copy.c +++ b/gcc/tree-ssa-copy.c @@ -129,8 +129,6 @@ may_propagate_copy (tree dest, tree orig) tree mt_orig = symbol_mem_tag (SSA_NAME_VAR (orig)); if (mt_dest && mt_orig && mt_dest != mt_orig) return false; - else if (!useless_type_conversion_p (type_d, type_o)) - return false; else if (get_alias_set (TREE_TYPE (type_d)) != get_alias_set (TREE_TYPE (type_o))) return false; @@ -217,31 +215,13 @@ merge_alias_info (tree orig_name, tree new_name) return; } - gcc_assert (POINTER_TYPE_P (TREE_TYPE (orig_name))); - gcc_assert (POINTER_TYPE_P (TREE_TYPE (new_name))); + gcc_assert (POINTER_TYPE_P (TREE_TYPE (orig_name)) + && POINTER_TYPE_P (TREE_TYPE (new_name))); #if defined ENABLE_CHECKING gcc_assert (useless_type_conversion_p (TREE_TYPE (orig_name), TREE_TYPE (new_name))); - /* If the pointed-to alias sets are different, these two pointers - would never have the same memory tag. In this case, NEW should - not have been propagated into ORIG. */ - gcc_assert (get_alias_set (TREE_TYPE (TREE_TYPE (new_sym))) - == get_alias_set (TREE_TYPE (TREE_TYPE (orig_sym)))); -#endif - - /* Synchronize the symbol tags. If both pointers had a tag and they - are different, then something has gone wrong. Symbol tags can - always be merged because they are flow insensitive, all the SSA - names of the same base DECL share the same symbol tag. */ - if (new_ann->symbol_mem_tag == NULL_TREE) - new_ann->symbol_mem_tag = orig_ann->symbol_mem_tag; - else if (orig_ann->symbol_mem_tag == NULL_TREE) - orig_ann->symbol_mem_tag = new_ann->symbol_mem_tag; - else - gcc_assert (new_ann->symbol_mem_tag == orig_ann->symbol_mem_tag); - /* Check that flow-sensitive information is compatible. Notice that we may not merge flow-sensitive information here. This function is called when propagating equivalences dictated by the IL, like @@ -257,7 +237,11 @@ merge_alias_info (tree orig_name, tree new_name) Since we cannot distinguish one case from another in this function, we can only make sure that if P_i and Q_j have - flow-sensitive information, they should be compatible. */ + flow-sensitive information, they should be compatible. + + As callers of merge_alias_info are supposed to call may_propagate_copy + first, the following check is redundant. Thus, only do it if checking + is enabled. */ if (SSA_NAME_PTR_INFO (orig_name) && SSA_NAME_PTR_INFO (new_name)) { struct ptr_info_def *orig_ptr_info = SSA_NAME_PTR_INFO (orig_name); @@ -278,7 +262,33 @@ merge_alias_info (tree orig_name, tree new_name) gcc_assert (bitmap_intersect_p (new_ptr_info->pt_vars, orig_ptr_info->pt_vars)); } -} +#endif + + /* Synchronize the symbol tags. If both pointers had a tag and they + are different, then something has gone wrong. Symbol tags can + always be merged because they are flow insensitive, all the SSA + names of the same base DECL share the same symbol tag. */ + if (new_ann->symbol_mem_tag == NULL_TREE) + new_ann->symbol_mem_tag = orig_ann->symbol_mem_tag; + else if (orig_ann->symbol_mem_tag == NULL_TREE) + orig_ann->symbol_mem_tag = new_ann->symbol_mem_tag; + else + gcc_assert (new_ann->symbol_mem_tag == orig_ann->symbol_mem_tag); + + /* Copy flow-sensitive alias information in case that NEW_NAME + didn't get a NMT but was set to pt_anything for optimization + purposes. In case ORIG_NAME has a NMT we can safely use its + flow-sensitive alias information as a conservative estimate. */ + if (SSA_NAME_PTR_INFO (orig_name) + && SSA_NAME_PTR_INFO (orig_name)->name_mem_tag + && (!SSA_NAME_PTR_INFO (new_name) + || !SSA_NAME_PTR_INFO (new_name)->name_mem_tag)) + { + struct ptr_info_def *orig_ptr_info = SSA_NAME_PTR_INFO (orig_name); + struct ptr_info_def *new_ptr_info = get_ptr_info (new_name); + memcpy (new_ptr_info, orig_ptr_info, sizeof (struct ptr_info_def)); + } +} /* Common code for propagate_value and replace_exp. diff --git a/gcc/tree-ssa-operands.c b/gcc/tree-ssa-operands.c index 36cf6240567..96ed4ca5cb5 100644 --- a/gcc/tree-ssa-operands.c +++ b/gcc/tree-ssa-operands.c @@ -1643,16 +1643,18 @@ get_addr_dereference_operands (tree stmt, tree *addr, int flags, tree full_ref, /* If we are emitting debugging dumps, display a warning if PTR is an SSA_NAME with no flow-sensitive alias information. That means that we may need to compute - aliasing again. */ + aliasing again or that a propagation pass forgot to + update the alias information on the pointers. */ if (dump_file && TREE_CODE (ptr) == SSA_NAME - && pi == NULL) + && (pi == NULL + || pi->name_mem_tag == NULL_TREE)) { fprintf (dump_file, "NOTE: no flow-sensitive alias info for "); print_generic_expr (dump_file, ptr, dump_flags); fprintf (dump_file, " in "); - print_generic_stmt (dump_file, stmt, dump_flags); + print_generic_stmt (dump_file, stmt, 0); } if (TREE_CODE (ptr) == SSA_NAME) -- 2.30.2