diff options
| -rw-r--r-- | gcc/cp/ChangeLog | 6 | ||||
| -rw-r--r-- | gcc/cp/constexpr.c | 21 | ||||
| -rw-r--r-- | gcc/cp/decl.c | 14 | ||||
| -rw-r--r-- | gcc/testsuite/g++.dg/opt/flifetime-dse2.C | 27 |
4 files changed, 64 insertions, 4 deletions
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog index b18c2fb..bbfba2b 100644 --- a/gcc/cp/ChangeLog +++ b/gcc/cp/ChangeLog @@ -1,5 +1,11 @@ 2015-04-15 Jason Merrill <jason@redhat.com> + * constexpr.c (cxx_eval_store_expression): Ignore clobbers. + (build_constexpr_constructor_member_initializers): Loop to find + the BIND_EXPR. + * decl.c (start_preparsed_function): Clobber the object at the + beginning of a constructor. + * decl.c (grokmethod): Only set DECL_COMDAT if TREE_PUBLIC is set. * method.c (implicitly_declare_fn): Likewise. * decl2.c (vague_linkage_p): Check TREE_PUBLIC first. diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c index 60f0a79..2990519 100644 --- a/gcc/cp/constexpr.c +++ b/gcc/cp/constexpr.c @@ -543,7 +543,16 @@ build_constexpr_constructor_member_initializers (tree type, tree body) || TREE_CODE (body) == EH_SPEC_BLOCK) body = TREE_OPERAND (body, 0); if (TREE_CODE (body) == STATEMENT_LIST) - body = STATEMENT_LIST_HEAD (body)->stmt; + { + tree_stmt_iterator i = tsi_start (body); + while (true) + { + body = tsi_stmt (i); + if (TREE_CODE (body) == BIND_EXPR) + break; + tsi_next (&i); + } + } body = BIND_EXPR_BODY (body); if (TREE_CODE (body) == CLEANUP_POINT_EXPR) { @@ -2552,6 +2561,11 @@ cxx_eval_store_expression (const constexpr_ctx *ctx, tree t, { constexpr_ctx new_ctx = *ctx; + tree init = TREE_OPERAND (t, 1); + if (TREE_CLOBBER_P (init)) + /* Just ignore clobbers. */ + return void_node; + /* First we figure out where we're storing to. */ tree target = TREE_OPERAND (t, 0); target = cxx_eval_constant_expression (ctx, target, @@ -2633,9 +2647,8 @@ cxx_eval_store_expression (const constexpr_ctx *ctx, tree t, new_ctx.object = target; } - tree init = cxx_eval_constant_expression (&new_ctx, TREE_OPERAND (t, 1), - false, - non_constant_p, overflow_p); + init = cxx_eval_constant_expression (&new_ctx, init, false, + non_constant_p, overflow_p); if (target == object) /* The hash table might have moved since the get earlier. */ ctx->values->put (object, init); diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c index 0538570..965f07c 100644 --- a/gcc/cp/decl.c +++ b/gcc/cp/decl.c @@ -13708,6 +13708,20 @@ start_preparsed_function (tree decl1, tree attrs, int flags) store_parm_decls (current_function_parms); + if (!processing_template_decl + && flag_lifetime_dse && DECL_CONSTRUCTOR_P (decl1)) + { + /* Insert a clobber to let the back end know that the object storage + is dead when we enter the constructor. */ + tree btype = CLASSTYPE_AS_BASE (current_class_type); + tree clobber = build_constructor (btype, NULL); + TREE_THIS_VOLATILE (clobber) = true; + tree bref = build_nop (build_reference_type (btype), current_class_ptr); + bref = convert_from_reference (bref); + tree exprstmt = build2 (MODIFY_EXPR, btype, bref, clobber); + finish_expr_stmt (exprstmt); + } + return true; } diff --git a/gcc/testsuite/g++.dg/opt/flifetime-dse2.C b/gcc/testsuite/g++.dg/opt/flifetime-dse2.C new file mode 100644 index 0000000..16d9a74 --- /dev/null +++ b/gcc/testsuite/g++.dg/opt/flifetime-dse2.C @@ -0,0 +1,27 @@ +// { dg-options "-O3 -flifetime-dse" } +// { dg-do run } + +typedef __SIZE_TYPE__ size_t; +inline void * operator new (size_t, void *p) { return p; } + +struct A +{ + int i; + A() {} + ~A() {} +}; + +int main() +{ + int ar[1] = { 42 }; + A* ap = new(ar) A; + + // When the constructor starts the object has indeterminate value. + if (ap->i == 42) __builtin_abort(); + + ap->i = 42; + ap->~A(); + + // When the destructor ends the object no longer exists. + if (ar[0] == 42) __builtin_abort(); +} |