/* PR middle-end/78476 - snprintf(0, 0, ...) with known arguments not optimized away PR middle-end/78512 - r242674 miscompiles Linux kernel A negative test complementing builtin-sprintf-5.c to verify that calls to the function that do not return a constant are not optimized away. Test also verifies that unknown directives prevent the optimization. { dg-compile } { dg-options "-O2 -Wformat -fdump-tree-optimized" } { dg-require-effective-target int32plus } */ typedef __SIZE_TYPE__ size_t; #define CONCAT(a, b) a ## b #define CAT(a, b) CONCAT (a, b) #define T(...) \ do { \ int CAT (n, __LINE__) = __builtin_snprintf (0, 0, __VA_ARGS__); \ sink (CAT (n, __LINE__)); \ } while (0) void sink (int); static int int_range (int min, int max) { extern int int_value (void); int val = int_value (); if (val < min || max < val) val = min; return val; } #define R(min, max) int_range (min, max) void test_arg_int (int width, int prec, int i, int n) { T ("%i", i); T ("%1i", i); T ("%2i", i); T ("%3i", i); T ("%4i", i); T ("%*i", width, 0); T ("%*i", width, 1); T ("%*i", width, i); T ("%.*i", prec, 0); T ("%.*i", prec, 1); T ("%.*i", prec, i); T ("%.*i", 0, i); T ("%i", R (1, 10)); /* Each of the bounds of the ranges below results in just one byte on output because they convert to the value 9 in type char, yet other values in those ranges can result in up to four bytes. For example, 4240 converts to -112. Verify that the output isn't folded into a constant. This assumes __CHAR_BIT__ of 8. */ T ("%hhi", R (4104, 4360) + 1); T ("%hhu", R (4104, 4360) + 1); /* Here, the range includes all possible lengths of output for a 16-bit short and 32-bit int. */ T ("%hi", R (65536, 65536 * 2)); T ("%hu", R (65536, 65536 * 2)); T ("%'i", 1234567); for (i = -n; i != n; ++i) T ("%*x", n, i); } /* Support for %p was removed in response to PR middle-end/78512 due to the Linux kernel relying on GCC builtins while at the same time providing a large number of extensions to the %p directive that interfere with the optimization. Verify that %p disables it. */ void test_arg_ptr (int width, int prec, int i) { T ("%p", (void*)0); T ("p=%p", (void*)0); T ("%s=%p", "p=", (void*)0); T ("%i%p", 123, (void*)0); } void test_arg_string (int width, int prec, const char *s) { T ("%-s", s); T ("%1s", s); T ("%.1s", s); T ("%*s", width, s); T ("%.*s", prec, s); T ("%1.*s", prec, s); T ("%*.1s", width, s); T ("%*.*s", width, prec, s); T ("%*s", width, "123"); T ("%.*s", prec, "123"); T ("%1.*s", prec, "123"); T ("%*.1s", width, "123"); T ("%*.*s", width, prec, "123"); } void test_invalid_directive (void) { T ("%"); /* { dg-warning "spurious trailing .%." } */ T ("abc%"); /* { dg-warning "spurious trailing .%." } */ T ("%2$i"); /* { dg-warning "operand number out of range" } */ T ("abc%2$i"); /* { dg-warning "operand number out of range" } */ T ("%=i", 0); /* { dg-warning "unknown conversion type character .=." } */ /* { dg-warning "too many arguments" "" { target *-*-* } .-1 } */ T ("%*i", "", 0); /* { dg-warning "field width specifier .\\*. expects argument of type .int." } */ T ("%.*i", "", 0); /* { dg-warning "field precision specifier .\\.\\*. expects argument of type .int." } */ T ("%.*.i", 0); /* { dg-warning "unknown conversion type character .\\.." } */ T ("%Q"); /* { dg-warning "unknown conversion type character .Q." } */ T ("abc%Q"); /* { dg-warning "unknown conversion type character .Q." } */ } /* Use 'grep "^ *T (" builtin-sprintf-6.c | wc -l' to determine the count for the directive below. { dg-final { scan-tree-dump-times "snprintf" 46 "optimized"} } */