From b0832fe1f38ce3553cb4d3b91b4821565c9d0d36 Mon Sep 17 00:00:00 2001 From: Jakub Jelinek Date: Fri, 4 Jan 2002 22:03:20 +0100 Subject: [PATCH] tree.h (expand_expr_stmt_value): Add maybe_last argument. * tree.h (expand_expr_stmt_value): Add maybe_last argument. * c-common.h (genrtl_expr_stmt_value): Likewise. * stmt.c (expand_expr_stmt): Pass 1 as maybe_last. (expand_expr_stmt_value): Add maybe_last argument. Don't warn about statement with no effect if it is the last statement in expression statement. * c-semantics.c (genrtl_expr_stmt): Pass 1 as maybe_last. (genrtl_expr_stmt_value): Add maybe_last argument, pass it down to expand_expr_stmt_value. (expand_stmt) [EXPR_STMT]: Pass 1 as maybe_last to genrtl_expr_stmt_value if t is the last EXPR_STMT in its scope. * expr.c (expand_expr) [LABELED_BLOCK_EXPR, LOOP_EXPR]: Pass 1 as maybe_last to expand_expr_stmt_value. * gcc.dg/20020104-1.c: New test. From-SVN: r48541 --- gcc/ChangeLog | 16 ++++++++++++++++ gcc/c-common.h | 2 +- gcc/c-semantics.c | 17 +++++++++++------ gcc/expr.c | 4 ++-- gcc/stmt.c | 12 +++++++----- gcc/testsuite/ChangeLog | 4 ++++ gcc/testsuite/gcc.dg/20020104-1.c | 22 ++++++++++++++++++++++ gcc/tree.h | 2 +- 8 files changed, 64 insertions(+), 15 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/20020104-1.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 765c1db5a9d..ad2c5eff834 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,19 @@ +2002-01-04 Jakub Jelinek + + * tree.h (expand_expr_stmt_value): Add maybe_last argument. + * c-common.h (genrtl_expr_stmt_value): Likewise. + * stmt.c (expand_expr_stmt): Pass 1 as maybe_last. + (expand_expr_stmt_value): Add maybe_last argument. + Don't warn about statement with no effect if it is the last statement + in expression statement. + * c-semantics.c (genrtl_expr_stmt): Pass 1 as maybe_last. + (genrtl_expr_stmt_value): Add maybe_last argument, pass it down to + expand_expr_stmt_value. + (expand_stmt) [EXPR_STMT]: Pass 1 as maybe_last to + genrtl_expr_stmt_value if t is the last EXPR_STMT in its scope. + * expr.c (expand_expr) [LABELED_BLOCK_EXPR, LOOP_EXPR]: Pass 1 + as maybe_last to expand_expr_stmt_value. + Fri Jan 4 11:45:05 2002 Jeffrey A Law (law@redhat.com) * c-common.c (c_expand_start_cond): Expect the IF_STMT node to diff --git a/gcc/c-common.h b/gcc/c-common.h index 296c9af3ac3..873021bc2db 100644 --- a/gcc/c-common.h +++ b/gcc/c-common.h @@ -721,7 +721,7 @@ extern void add_c_tree_codes PARAMS ((void)); extern void genrtl_do_pushlevel PARAMS ((void)); extern void genrtl_goto_stmt PARAMS ((tree)); extern void genrtl_expr_stmt PARAMS ((tree)); -extern void genrtl_expr_stmt_value PARAMS ((tree, int)); +extern void genrtl_expr_stmt_value PARAMS ((tree, int, int)); extern void genrtl_decl_stmt PARAMS ((tree)); extern void genrtl_if_stmt PARAMS ((tree)); extern void genrtl_while_stmt PARAMS ((tree)); diff --git a/gcc/c-semantics.c b/gcc/c-semantics.c index ef9ba333751..4bab4d3aaa6 100644 --- a/gcc/c-semantics.c +++ b/gcc/c-semantics.c @@ -313,18 +313,20 @@ void genrtl_expr_stmt (expr) tree expr; { - genrtl_expr_stmt_value (expr, -1); + genrtl_expr_stmt_value (expr, -1, 1); } /* Generate the RTL for EXPR, which is an EXPR_STMT. WANT_VALUE tells whether to (1) save the value of the expression, (0) discard it or (-1) use expr_stmts_for_value to tell. The use of -1 is - deprecated, and retained only for backward compatibility. */ + deprecated, and retained only for backward compatibility. + MAYBE_LAST is non-zero if this EXPR_STMT might be the last statement + in expression statement. */ void -genrtl_expr_stmt_value (expr, want_value) +genrtl_expr_stmt_value (expr, want_value, maybe_last) tree expr; - int want_value; + int want_value, maybe_last; { if (expr != NULL_TREE) { @@ -334,7 +336,7 @@ genrtl_expr_stmt_value (expr, want_value) expand_start_target_temps (); if (expr != error_mark_node) - expand_expr_stmt_value (expr, want_value); + expand_expr_stmt_value (expr, want_value, maybe_last); if (stmts_are_full_exprs_p ()) expand_end_target_temps (); @@ -763,7 +765,10 @@ expand_stmt (t) break; case EXPR_STMT: - genrtl_expr_stmt_value (EXPR_STMT_EXPR (t), TREE_ADDRESSABLE (t)); + genrtl_expr_stmt_value (EXPR_STMT_EXPR (t), TREE_ADDRESSABLE (t), + TREE_CHAIN (t) == NULL + || (TREE_CODE (TREE_CHAIN (t)) == SCOPE_STMT + && TREE_CHAIN (TREE_CHAIN (t)) == NULL)); break; case DECL_STMT: diff --git a/gcc/expr.c b/gcc/expr.c index b07d88d41fa..04d801de76f 100644 --- a/gcc/expr.c +++ b/gcc/expr.c @@ -6453,7 +6453,7 @@ expand_expr (exp, target, tmode, modifier) case LABELED_BLOCK_EXPR: if (LABELED_BLOCK_BODY (exp)) - expand_expr_stmt_value (LABELED_BLOCK_BODY (exp), 0); + expand_expr_stmt_value (LABELED_BLOCK_BODY (exp), 0, 1); /* Should perhaps use expand_label, but this is simpler and safer. */ do_pending_stack_adjust (); emit_label (label_rtx (LABELED_BLOCK_LABEL (exp))); @@ -6468,7 +6468,7 @@ expand_expr (exp, target, tmode, modifier) case LOOP_EXPR: push_temp_slots (); expand_start_loop (1); - expand_expr_stmt_value (TREE_OPERAND (exp, 0), 0); + expand_expr_stmt_value (TREE_OPERAND (exp, 0), 0, 1); expand_end_loop (); pop_temp_slots (); diff --git a/gcc/stmt.c b/gcc/stmt.c index 16a3882ffd0..6933599a89e 100644 --- a/gcc/stmt.c +++ b/gcc/stmt.c @@ -2190,7 +2190,7 @@ void expand_expr_stmt (exp) tree exp; { - expand_expr_stmt_value (exp, -1); + expand_expr_stmt_value (exp, -1, 1); } /* Generate RTL to evaluate the expression EXP. WANT_VALUE tells @@ -2199,9 +2199,9 @@ expand_expr_stmt (exp) deprecated, and retained only for backward compatibility. */ void -expand_expr_stmt_value (exp, want_value) +expand_expr_stmt_value (exp, want_value, maybe_last) tree exp; - int want_value; + int want_value, maybe_last; { rtx value; tree type; @@ -2211,8 +2211,10 @@ expand_expr_stmt_value (exp, want_value) /* If -W, warn about statements with no side effects, except for an explicit cast to void (e.g. for assert()), and - except inside a ({...}) where they may be useful. */ - if (! want_value && exp != error_mark_node) + except for last statement in ({...}) where they may be useful. */ + if (! want_value + && (expr_stmts_for_value == 0 || ! maybe_last) + && exp != error_mark_node) { if (! TREE_SIDE_EFFECTS (exp)) { diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index ec0bdab5943..657035c2845 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,7 @@ +2002-01-04 Jakub Jelinek + + * gcc.dg/20020104-1.c: New test. + 2002-01-04 Hans-Peter Nilsson * gcc.dg/20020103-1.c: Fix typo in target selector. diff --git a/gcc/testsuite/gcc.dg/20020104-1.c b/gcc/testsuite/gcc.dg/20020104-1.c new file mode 100644 index 00000000000..be36a7427ae --- /dev/null +++ b/gcc/testsuite/gcc.dg/20020104-1.c @@ -0,0 +1,22 @@ +/* Test whether statement with no effect warnings are not given for last + statements inside of statement expression. */ +/* { dg-do compile } */ +/* { dg-options "-O -Wall" } */ + +void bar (char *p, char *q); + +int main() +{ + char foo [32], *p; + + ({ + void *s = (foo); + __builtin_memset (s, '\0', sizeof (foo)); + s; /* { dg-warning "no effect" "statement with no effect warning" } */ + s; /* { dg-bogus "no effect" "bogus statement with no effect warning" } */ + }); + p = foo; + p; /* { dg-warning "no effect" "statement with no effect warning" } */ + bar (foo, p); + return 0; +} diff --git a/gcc/tree.h b/gcc/tree.h index 208e6d0a78b..642b5554389 100644 --- a/gcc/tree.h +++ b/gcc/tree.h @@ -2720,7 +2720,7 @@ extern void expand_fixups PARAMS ((rtx)); extern tree expand_start_stmt_expr PARAMS ((void)); extern tree expand_end_stmt_expr PARAMS ((tree)); extern void expand_expr_stmt PARAMS ((tree)); -extern void expand_expr_stmt_value PARAMS ((tree, int)); +extern void expand_expr_stmt_value PARAMS ((tree, int, int)); extern int warn_if_unused_value PARAMS ((tree)); extern void expand_decl_init PARAMS ((tree)); extern void clear_last_expr PARAMS ((void)); -- 2.30.2