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re PR tree-optimization/78965 (Invalid -fprintf-return-value optimization) 

PR tree-optimization/78965
	* gimple-ssa-sprintf.c (pass_sprintf_length::compute_format_length):
	Change first argument from const call_info & to call_info &.  For %n
	set info.nowrite to false.

	* gcc.dg/pr78965.c: New test.

From-SVN: r244014
This commit is contained in:
Jakub Jelinek 2017-01-03 08:23:11 +01:00 committed by Jakub Jelinek
parent cd123354c5
commit 51ad5d5ba3
4 changed files with 29 additions and 3 deletions
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5
gcc/ChangeLog
View File

@ -1,5 +1,10 @@
2017-01-03 Jakub Jelinek <jakub@redhat.com>
PR tree-optimization/78965
* gimple-ssa-sprintf.c (pass_sprintf_length::compute_format_length):
Change first argument from const call_info & to call_info &. For %n
set info.nowrite to false.
PR middle-end/78901
* gimple-ssa-sprintf.c (try_substitute_return_value): Don't change
possibly throwing calls.

10
gcc/gimple-ssa-sprintf.c
View File

@ -131,7 +131,7 @@ public:
void handle_gimple_call (gimple_stmt_iterator*);
struct call_info;
bool compute_format_length (const call_info &, format_result *);
bool compute_format_length (call_info &, format_result *);
};
bool
@ -710,7 +710,8 @@ struct pass_sprintf_length::call_info
/* True for bounded functions like snprintf that specify a zero-size
buffer as a request to compute the size of output without actually
writing any. */
writing any. NOWRITE is cleared in response to the %n directive
which has side-effects similar to writing output. */
bool nowrite;
};
@ -2357,7 +2358,7 @@ add_bytes (const pass_sprintf_length::call_info &info,
that caused the processing to be terminated early). */
bool
pass_sprintf_length::compute_format_length (const call_info &info,
pass_sprintf_length::compute_format_length (call_info &info,
format_result *res)
{
/* The variadic argument counter. */
@ -2624,6 +2625,9 @@ pass_sprintf_length::compute_format_length (const call_info &info,
return false;
case 'n':
/* %n has side-effects even when nothing is actually printed to
any buffer. */
info.nowrite = false;
break;
case 'c':

3
gcc/testsuite/ChangeLog
View File

@ -1,5 +1,8 @@
2017-01-03 Jakub Jelinek <jakub@redhat.com>
PR tree-optimization/78965
* gcc.dg/pr78965.c: New test.
PR middle-end/78901
* g++.dg/opt/pr78901.C: New test.

14
gcc/testsuite/gcc.dg/pr78965.c Normal file
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@ -0,0 +1,14 @@
/* PR tree-optimization/78965 */
/* { dg-do run { target c99_runtime } } */
/* { dg-options "-O2" } */
/* { dg-add-options c99_runtime } */
int
main ()
{
int a = 5, b = 6;
int c = __builtin_snprintf (0, 0, "a%nb%nc", &a, &b);
if (a + b + c != 6)
__builtin_abort ();
return 0;
}