diff --git a/gcc/testsuite/c-c++-common/Wmemset-transposed-args1.c b/gcc/testsuite/c-c++-common/Wmemset-transposed-args1.c
index d188d6f..923fb92 100644
--- a/gcc/testsuite/c-c++-common/Wmemset-transposed-args1.c
+++ b/gcc/testsuite/c-c++-common/Wmemset-transposed-args1.c
@@ -10,7 +10,7 @@ void *memset (void *, int, size_t);
 char buf[1024];
 
 void
-foo ()
+foo (void)
 {
   memset (buf, sizeof buf, 0);	/* { dg-warning ".memset. used with constant zero length parameter; this could be due to transposed parameters" } */
   memset (buf, sizeof buf, '\0'); /* { dg-warning ".memset. used with constant zero length parameter; this could be due to transposed parameters" } */
diff --git a/gcc/testsuite/c-c++-common/Wmemset-transposed-args2.c b/gcc/testsuite/c-c++-common/Wmemset-transposed-args2.c
index 8647138..c77107f 100644
--- a/gcc/testsuite/c-c++-common/Wmemset-transposed-args2.c
+++ b/gcc/testsuite/c-c++-common/Wmemset-transposed-args2.c
@@ -11,7 +11,7 @@ void *memset (void *, int, size_t);
 char buf[1024];
 
 void
-foo ()
+foo (void)
 {
   memset (buf, sizeof buf, u'\0'); /* { dg-warning ".memset. used with constant zero length parameter; this could be due to transposed parameters" } */
   memset (buf, sizeof buf, U'\0'); /* { dg-warning ".memset. used with constant zero length parameter; this could be due to transposed parameters" } */
diff --git a/gcc/testsuite/c-c++-common/attr-used-2.c b/gcc/testsuite/c-c++-common/attr-used-2.c
index f78b94b..ba532d5 100644
--- a/gcc/testsuite/c-c++-common/attr-used-2.c
+++ b/gcc/testsuite/c-c++-common/attr-used-2.c
@@ -3,7 +3,7 @@
 
 static int xyzzy __attribute__((__used__)) = 1; 
 
-void foo()
+void foo(void)
 {
   int x __attribute__((__used__)); /* { dg-warning "attribute ignored|unused variable" } */
 }
diff --git a/gcc/testsuite/c-c++-common/dfp/func-mixed.c b/gcc/testsuite/c-c++-common/dfp/func-mixed.c
index 6f7e2eb..4543144 100644
--- a/gcc/testsuite/c-c++-common/dfp/func-mixed.c
+++ b/gcc/testsuite/c-c++-common/dfp/func-mixed.c
@@ -144,7 +144,7 @@ arg5_128 (int arg0, unsigned int arg1, float arg2,
 
 
 int
-main ()
+main (void)
 {
   /* _Decimal32 variants.  */
   if (arg0_32 (0.0df, -1, 2, 3.0f, 4.0, 5.0l) != 0.0df) FAILURE
diff --git a/gcc/testsuite/c-c++-common/gomp/pr58472.c b/gcc/testsuite/c-c++-common/gomp/pr58472.c
index 355ca40..4ef6b08 100644
--- a/gcc/testsuite/c-c++-common/gomp/pr58472.c
+++ b/gcc/testsuite/c-c++-common/gomp/pr58472.c
@@ -5,7 +5,7 @@
 float a[1024], b[1024];
 
 float
-foo ()
+foo (void)
 {
   float s = 0.f;
   unsigned int i;
diff --git a/gcc/testsuite/c-c++-common/ubsan/ptr-overflow-1.c b/gcc/testsuite/c-c++-common/ubsan/ptr-overflow-1.c
index 8edfbce..673ce57 100644
--- a/gcc/testsuite/c-c++-common/ubsan/ptr-overflow-1.c
+++ b/gcc/testsuite/c-c++-common/ubsan/ptr-overflow-1.c
@@ -21,7 +21,7 @@ struct S s;
 int *volatile r;
 
 int
-main ()
+main (void)
 {
   struct S t;
   p = &a[32];
diff --git a/gcc/testsuite/c-c++-common/ubsan/ptr-overflow-2.c b/gcc/testsuite/c-c++-common/ubsan/ptr-overflow-2.c
index a1110a2..3883668 100644
--- a/gcc/testsuite/c-c++-common/ubsan/ptr-overflow-2.c
+++ b/gcc/testsuite/c-c++-common/ubsan/ptr-overflow-2.c
@@ -35,7 +35,7 @@ struct S *volatile q;
 int *volatile r;
 
 int
-main ()
+main (void)
 {
   u = ~(__UINTPTR_TYPE__) 0;
   p = (char *) u;
diff --git a/gcc/testsuite/gcc.dg/20020104-1.c b/gcc/testsuite/gcc.dg/20020104-1.c
index be36a74..dc9284d 100644
--- a/gcc/testsuite/gcc.dg/20020104-1.c
+++ b/gcc/testsuite/gcc.dg/20020104-1.c
@@ -5,7 +5,7 @@
 
 void bar (char *p, char *q);
 
-int main()
+int main (void)
 {
   char foo [32], *p;
 
diff --git a/gcc/testsuite/gcc.dg/Warray-bounds-4.c b/gcc/testsuite/gcc.dg/Warray-bounds-4.c
index 71526f2..c5da844 100644
--- a/gcc/testsuite/gcc.dg/Warray-bounds-4.c
+++ b/gcc/testsuite/gcc.dg/Warray-bounds-4.c
@@ -10,7 +10,7 @@ static void g(DWORD * p, int n)
         for (i = 0; i < n && !p[n - 1]; i++);  /* { dg-bogus "subscript is above array bounds" } */
 }
 
-void f() {
+void f(void) {
         DWORD arr[8];
 
         g(arr, 4);
diff --git a/gcc/testsuite/gcc.dg/Wmissing-parameter-type-no.c b/gcc/testsuite/gcc.dg/Wmissing-parameter-type-no.c
index 45e5e42..b03a6c2 100644
--- a/gcc/testsuite/gcc.dg/Wmissing-parameter-type-no.c
+++ b/gcc/testsuite/gcc.dg/Wmissing-parameter-type-no.c
@@ -4,4 +4,4 @@
 
 int foo(bar) { return bar;} /* { dg-bogus "type of 'bar' defaults to 'int'" } */
 
-
+/* { dg-prune-output "\\\[-Wstrict-prototypes]" } */
diff --git a/gcc/testsuite/gcc.dg/Wstrict-overflow-21.c b/gcc/testsuite/gcc.dg/Wstrict-overflow-21.c
index 82a61d9..67575b6 100644
--- a/gcc/testsuite/gcc.dg/Wstrict-overflow-21.c
+++ b/gcc/testsuite/gcc.dg/Wstrict-overflow-21.c
@@ -2,7 +2,7 @@
 /* { dg-do compile } */
 /* { dg-options "-fstrict-overflow -O2 -Wstrict-overflow=2 -Wall" } */
 int
-foo ()
+foo (void)
 {
   int i, bits;
   for (i = 1, bits = 1; i > 0; i += i) /* { dg-warning "assuming signed overflow does not occur" "correct warning" { xfail *-*-* } } */
diff --git a/gcc/testsuite/gcc.dg/Wstring-literal-comparison-2.c b/gcc/testsuite/gcc.dg/Wstring-literal-comparison-2.c
index 3eb91ee..90f75fe 100644
--- a/gcc/testsuite/gcc.dg/Wstring-literal-comparison-2.c
+++ b/gcc/testsuite/gcc.dg/Wstring-literal-comparison-2.c
@@ -7,22 +7,22 @@ int test1(char *ptr)
   return ptr == "foo";  /* { dg-warning "comparison with string" } */
 }
 
-int test2()
+int test2 (void)
 {
   return "foo" != (const char*)0;
 }
 
-int test3()
+int test3 (void)
 {
   return "foo" == (const char*)0;
 }
 
-int test4()
+int test4 (void)
 {
   return (const char*)0 != "foo";
 }
 
-int test5()
+int test5 (void)
 {
   return (const char*)0 == "foo";
 }
diff --git a/gcc/testsuite/gcc.dg/Wstring-literal-comparison-4.c b/gcc/testsuite/gcc.dg/Wstring-literal-comparison-4.c
index f2a711a..238e9f7 100644
--- a/gcc/testsuite/gcc.dg/Wstring-literal-comparison-4.c
+++ b/gcc/testsuite/gcc.dg/Wstring-literal-comparison-4.c
@@ -7,22 +7,22 @@ int test1(char *ptr)
   return ptr == "foo";
 }
 
-int test2()
+int test2 (void)
 {
   return "foo" != (const char*)0;
 }
 
-int test3()
+int test3 (void)
 {
   return "foo" == (const char*)0;
 }
 
-int test4()
+int test4 (void)
 {
   return (const char*)0 != "foo";
 }
 
-int test5()
+int test5 (void)
 {
   return (const char*)0 == "foo";
 }
diff --git a/gcc/testsuite/gcc.dg/builtin-choose-expr.c b/gcc/testsuite/gcc.dg/builtin-choose-expr.c
index ceac605..9c48b85 100644
--- a/gcc/testsuite/gcc.dg/builtin-choose-expr.c
+++ b/gcc/testsuite/gcc.dg/builtin-choose-expr.c
@@ -34,15 +34,15 @@
         } while (0)
 
 
-extern void abort ();
-extern void exit ();
+extern void abort (void);
+extern void exit (void);
 
-void bad ()
+void bad (void)
 {
   abort ();
 }
 
-void good ()
+void good (void)
 {
   exit (0);
 }
diff --git a/gcc/testsuite/gcc.dg/builtins-30.c b/gcc/testsuite/gcc.dg/builtins-30.c
index 37e5dba..72721bf 100644
--- a/gcc/testsuite/gcc.dg/builtins-30.c
+++ b/gcc/testsuite/gcc.dg/builtins-30.c
@@ -25,3 +25,5 @@ long double cosl (foo, bar)  /* { dg-warning "shadows a built-in|number of argum
 {
   return strtod ("nan", 0);
 }
+
+/* { dg-prune-output "\\\[-Wstrict-prototypes]" } */
diff --git a/gcc/testsuite/gcc.dg/cleanup-1.c b/gcc/testsuite/gcc.dg/cleanup-1.c
index 48b8264..6231028 100644
--- a/gcc/testsuite/gcc.dg/cleanup-1.c
+++ b/gcc/testsuite/gcc.dg/cleanup-1.c
@@ -6,7 +6,7 @@
 #define C(x)	__attribute__((cleanup(x)))
 
 static int f1(void *x U) { return 0; }
-static void f2() { }
+static void f2() { } /* { dg-warning "\\\[-Wstrict-prototypes]" } */
 static void f3(void) { } /* { dg-message "note: declared here" } */
 static void f4(void *x U) { }
 static void f5(int *x U) { }
diff --git a/gcc/testsuite/gcc.dg/cpp/very-long-comment.c b/gcc/testsuite/gcc.dg/cpp/very-long-comment.c
index 88d8eb9..ac8bf57 100644
--- a/gcc/testsuite/gcc.dg/cpp/very-long-comment.c
+++ b/gcc/testsuite/gcc.dg/cpp/very-long-comment.c
@@ -7,7 +7,7 @@ This is a really long comment. This is a really long comment. This is a really l
 /* { dg-do compile } */
 #warning test warning /* { dg-warning "test warning" } */
 #include <stdio.h>
-int main()
+int main (void)
 {
   printf("This is line %d\n", __LINE__);
   return 0;
diff --git a/gcc/testsuite/gcc.dg/dfp/composite-type.c b/gcc/testsuite/gcc.dg/dfp/composite-type.c
index 6d461c7..f7e6a6d 100644
--- a/gcc/testsuite/gcc.dg/dfp/composite-type.c
+++ b/gcc/testsuite/gcc.dg/dfp/composite-type.c
@@ -45,7 +45,7 @@ DECIMAL_COMPOSITE_DECL(128); /* { dg-error "incompatible types when assigning to
 /* { dg-message "note: expected '\[^'\n\]*' but argument is of type '\[^'\n\]*'" "note: expected" { target *-*-* } .-1 } */
 
 
-int main()
+int main (void)
 {
   DECIMAL_COMPOSITE_TEST(32);  /* { dg-warning "incompatible pointer type" } */
   DECIMAL_COMPOSITE_TEST(64);  /* { dg-warning "incompatible pointer type" } */
@@ -53,3 +53,5 @@ int main()
 
   return 0;
 }
+
+/* { dg-prune-output "\\\[-Wstrict-prototypes]" } */
diff --git a/gcc/testsuite/gcc.dg/dfp/struct-union.c b/gcc/testsuite/gcc.dg/dfp/struct-union.c
index 956fdcf..cc14bea 100644
--- a/gcc/testsuite/gcc.dg/dfp/struct-union.c
+++ b/gcc/testsuite/gcc.dg/dfp/struct-union.c
@@ -31,7 +31,7 @@ union u h (union u u)
   return u;
 }
 
-void f()
+void f (void)
 {
   cs.d32 = 1.23dd; /* { dg-error "assignment of member 'd32' in read-only object" } */
   cs.d64 = 1.23df; /* { dg-error "assignment of member 'd64' in read-only object" } */
diff --git a/gcc/testsuite/gcc.dg/format/pr78680.c b/gcc/testsuite/gcc.dg/format/pr78680.c
index 0c599f3..3e9cb2b 100644
--- a/gcc/testsuite/gcc.dg/format/pr78680.c
+++ b/gcc/testsuite/gcc.dg/format/pr78680.c
@@ -1,7 +1,7 @@
 /* { dg-do compile } */
 /* { dg-options "-O2 -Wall -Wextra -fdiagnostics-show-caret" } */
 
-void fn1() {
+void fn1 (void) {
   __builtin_printf("\
      %ld.\n\
         2\n"); };
diff --git a/gcc/testsuite/gcc.dg/gomp/pr30421.c b/gcc/testsuite/gcc.dg/gomp/pr30421.c
index 901ba3c..8d3711e 100644
--- a/gcc/testsuite/gcc.dg/gomp/pr30421.c
+++ b/gcc/testsuite/gcc.dg/gomp/pr30421.c
@@ -3,7 +3,7 @@
 /* { dg-options "-O2 -fopenmp -Wall" } */
 
 int
-foo ()
+foo (void)
 {
   int a = 0, i;
 
@@ -15,7 +15,7 @@ foo ()
 }
 
 int
-bar ()
+bar (void)
 {
   int a = 0, i;
 
@@ -27,7 +27,7 @@ bar ()
 }
 
 int
-baz ()
+baz (void)
 {
   int a = 0, i;
 
diff --git a/gcc/testsuite/gcc.dg/gomp/pr34694.c b/gcc/testsuite/gcc.dg/gomp/pr34694.c
index 35cbf33..a494b85 100644
--- a/gcc/testsuite/gcc.dg/gomp/pr34694.c
+++ b/gcc/testsuite/gcc.dg/gomp/pr34694.c
@@ -5,7 +5,7 @@
 int i;
 
 void
-foo ()
+foo (void)
 {
 #pragma omp parallel
   {
diff --git a/gcc/testsuite/gcc.dg/ifelse-1.c b/gcc/testsuite/gcc.dg/ifelse-1.c
index 2dd2208..e8a7bfc 100644
--- a/gcc/testsuite/gcc.dg/ifelse-1.c
+++ b/gcc/testsuite/gcc.dg/ifelse-1.c
@@ -4,12 +4,11 @@
 */
 
 
-extern int bar ();
-extern int com ();
-extern int baz ();
+extern int bar (void);
+extern int com (void);
+extern int baz (void);
 void
-foo (a,b)
-     int a, b;
+foo (int a, b)
 {
   if (a)
     if (b)
diff --git a/gcc/testsuite/gcc.dg/m-un-1.c b/gcc/testsuite/gcc.dg/m-un-1.c
index ad84d44..ebcfc32 100644
--- a/gcc/testsuite/gcc.dg/m-un-1.c
+++ b/gcc/testsuite/gcc.dg/m-un-1.c
@@ -21,7 +21,7 @@ while loops, but that is presumably much much harder to test for.
 /* { dg-options "-O -Wall" } */
 
 int
-sub ()
+sub (void)
 {
   int i = 0;
   int j = 0;
diff --git a/gcc/testsuite/gcc.dg/misc-column.c b/gcc/testsuite/gcc.dg/misc-column.c
index e68300b..7465215 100644
--- a/gcc/testsuite/gcc.dg/misc-column.c
+++ b/gcc/testsuite/gcc.dg/misc-column.c
@@ -9,7 +9,7 @@ struct {
 	char b;
 } *q;
 
-extern void bar();
+extern void bar(void);
 
 void foo (void)
 {
diff --git a/gcc/testsuite/gcc.dg/pr12603.c b/gcc/testsuite/gcc.dg/pr12603.c
index f7caef2..5671806 100644
--- a/gcc/testsuite/gcc.dg/pr12603.c
+++ b/gcc/testsuite/gcc.dg/pr12603.c
@@ -2,7 +2,7 @@
 /* { dg-do compile } */
 /* { dg-options "-O3 -Wall -Wextra -Wreturn-type" } */
 int
-this_function_never_returns ()
+this_function_never_returns (void)
 {
   for (;;);
 }
diff --git a/gcc/testsuite/gcc.dg/pr18241-1.c b/gcc/testsuite/gcc.dg/pr18241-1.c
index a37e77d..d8417b2 100644
--- a/gcc/testsuite/gcc.dg/pr18241-1.c
+++ b/gcc/testsuite/gcc.dg/pr18241-1.c
@@ -89,7 +89,7 @@ out:
 	return ret;
 }
 
-int main ()
+int main (void)
 {
 	struct radix_tree_root r;
 	struct radix_tree_node node;
diff --git a/gcc/testsuite/gcc.dg/pr18241-2.c b/gcc/testsuite/gcc.dg/pr18241-2.c
index a3ff1de..7a81ca7 100644
--- a/gcc/testsuite/gcc.dg/pr18241-2.c
+++ b/gcc/testsuite/gcc.dg/pr18241-2.c
@@ -51,7 +51,7 @@ void radix_tree_tag_clear(struct radix_tree_root *root, unsigned long index)
 struct radix_tree_root r;
 struct radix_tree_node node;
 
-int main ()
+int main (void)
 {
   	r.height = 1;
 	r.rnode = &node;
diff --git a/gcc/testsuite/gcc.dg/pr35736.c b/gcc/testsuite/gcc.dg/pr35736.c
index f411bb8..2bf8166 100644
--- a/gcc/testsuite/gcc.dg/pr35736.c
+++ b/gcc/testsuite/gcc.dg/pr35736.c
@@ -1,7 +1,7 @@
 /* { dg-do compile } */
 /* { dg-options "-O -Wall" } */
 
-void foo()
+void foo (void)
 {
   while (1)
     for (;;({ continue; }))
diff --git a/gcc/testsuite/gcc.dg/pr49120.c b/gcc/testsuite/gcc.dg/pr49120.c
index 50993e6..203999a 100644
--- a/gcc/testsuite/gcc.dg/pr49120.c
+++ b/gcc/testsuite/gcc.dg/pr49120.c
@@ -4,7 +4,7 @@
 /* { dg-require-effective-target alloca } */
 
 int
-main ()
+main (void)
 {
   int a = 1;
   int c = ({ char b[a + 1]; b[0] = 0; b[0]; });
diff --git a/gcc/testsuite/gcc.dg/pr63748.c b/gcc/testsuite/gcc.dg/pr63748.c
index cc353a7..2c24379 100644
--- a/gcc/testsuite/gcc.dg/pr63748.c
+++ b/gcc/testsuite/gcc.dg/pr63748.c
@@ -4,7 +4,7 @@
 
 #include <setjmp.h>
 
-jmp_buf *alloc_jmp_buf ();
+jmp_buf *alloc_jmp_buf (void);
 int foo (void *);
 
 int
diff --git a/gcc/testsuite/gcc.dg/pr70281.c b/gcc/testsuite/gcc.dg/pr70281.c
index 9447fb1..d3bebff 100644
--- a/gcc/testsuite/gcc.dg/pr70281.c
+++ b/gcc/testsuite/gcc.dg/pr70281.c
@@ -1,5 +1,5 @@
 /* { dg-options "-Wall -fdiagnostics-show-caret" } */
-int bch_stats_show ()
+int bch_stats_show (void)
 {
   return __builtin_types_compatible_p (unsigned, int) ? "" : "";  /* { dg-warning "cast" } */
 /* { dg-begin-multiline-output "" }
diff --git a/gcc/testsuite/gcc.dg/pr79223.c b/gcc/testsuite/gcc.dg/pr79223.c
index ef0dd1b..018d8c5 100644
--- a/gcc/testsuite/gcc.dg/pr79223.c
+++ b/gcc/testsuite/gcc.dg/pr79223.c
@@ -13,7 +13,7 @@ char s[4];
 
 size_t range (void)
 {
-  extern size_t size ();
+  extern size_t size (void);
   size_t n = size ();
   if (n <= sizeof d)
     return sizeof d + 1;
diff --git a/gcc/testsuite/gcc.dg/simd-1.c b/gcc/testsuite/gcc.dg/simd-1.c
index e92662e..af5a597 100644
--- a/gcc/testsuite/gcc.dg/simd-1.c
+++ b/gcc/testsuite/gcc.dg/simd-1.c
@@ -19,7 +19,7 @@ int foo1;
 short foo2 __attribute__((vector_size (8)));
 
 void
-hanneke ()
+hanneke (void)
 {
   /* Assignment.  */
   a = b;
diff --git a/gcc/testsuite/gcc.dg/simd-1b.c b/gcc/testsuite/gcc.dg/simd-1b.c
index 44c39c2..b878a7a 100644
--- a/gcc/testsuite/gcc.dg/simd-1b.c
+++ b/gcc/testsuite/gcc.dg/simd-1b.c
@@ -11,7 +11,7 @@ v4si a, b;
 v2si c, d;
 
 void
-hanneke ()
+hanneke (void)
 {
   /* Operators on compatible SIMD types.  */
   a %= b;
diff --git a/gcc/testsuite/gcc.dg/simd-2.c b/gcc/testsuite/gcc.dg/simd-2.c
index 13e1cab..42cba7c 100644
--- a/gcc/testsuite/gcc.dg/simd-2.c
+++ b/gcc/testsuite/gcc.dg/simd-2.c
@@ -17,7 +17,7 @@ float foo1;
 v2sf foo2;
 
 void
-hanneke ()
+hanneke (void)
 {
   /* Assignment.  */
   a = b;
diff --git a/gcc/testsuite/gcc.dg/tm/unused.c b/gcc/testsuite/gcc.dg/tm/unused.c
index 7c8aa3e..e108f93 100644
--- a/gcc/testsuite/gcc.dg/tm/unused.c
+++ b/gcc/testsuite/gcc.dg/tm/unused.c
@@ -2,12 +2,12 @@
 /* { dg-options "-fgnu-tm -Wall" } */
 
 __attribute__((transaction_safe))
-static int unused_func ()	/* { dg-warning "defined but not used" } */
+static int unused_func (void)	/* { dg-warning "defined but not used" } */
 {
   return 12345;
 }
 
-int main()
+int main (void)
 {
   return 0;
 }
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/builtin-sprintf-warn-18.c b/gcc/testsuite/gcc.dg/tree-ssa/builtin-sprintf-warn-18.c
index 961fa48..54ebe23 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/builtin-sprintf-warn-18.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/builtin-sprintf-warn-18.c
@@ -11,7 +11,7 @@ void sink (void*);
 
 /* Exercise all special C and POSIX characters.  */
 
-void test_characters ()
+void test_characters (void)
 {
   T ("%%");           /* { dg-warning ".%%. directive writing 1 byte" } */
 
@@ -128,7 +128,7 @@ void test_width_and_precision_out_of_range (char *d)
 /* Verify that an excessively long directive is truncated and the truncation
    is indicated by three trailing dots in the text of the warning.  */
 
-void test_overlong_plain_string ()
+void test_overlong_plain_string (void)
 {
   static const char longfmtstr[] =
     "0123456789012345678901234567890123456789012345678901234567890123456789%%";
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/builtin-sprintf.c b/gcc/testsuite/gcc.dg/tree-ssa/builtin-sprintf.c
index eb27de6..6db9c5c 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/builtin-sprintf.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/builtin-sprintf.c
@@ -91,7 +91,7 @@ char* ptr = buffer;
 #  define TEST_FAILURE(line, ignore1, ignore2, ignore3)			\
   do {									\
     extern void CAT (failure_on_line_, line)(void);			\
-    CAT (failure_on_line_, line)();					\
+    CAT (failure_on_line_, line)(void);					\
   } while (0)
 #else
 /* The test is run by DejaGnu with optimization enabled.  When it's run
@@ -174,7 +174,7 @@ test_c (char c)
 unsigned __attribute__ ((noclone, noinline))
 unsigned_value (void)
 {
-  extern int rand ();
+  extern int rand (void);
   return rand ();
 }
 
@@ -183,7 +183,7 @@ unsigned_value (void)
 int __attribute__ ((noclone, noinline))
 int_value (void)
 {
-  extern int rand ();
+  extern int rand (void);
   return rand ();
 }
 
@@ -233,7 +233,7 @@ test_d_i (int i, long li)
   EQL ( 1, -1, "%i", uchar_range (0, 9));
 
   /* The range information available to passes other than the Value
-     Range Propoagation pass itself is so bad that the following two
+     Range Propagation pass itself is so bad that the following two
      tests fail (the range seen in the test below is [0, 99] rather
      than [10, 99].
   EQL ( 2,  3, "%i", uchar_range (10, 99));
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr79327.c b/gcc/testsuite/gcc.dg/tree-ssa/pr79327.c
index 7db875d..71458fe 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/pr79327.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr79327.c
@@ -8,7 +8,7 @@ char buf[64];
 #define FMT "%+03d%02d"
 const char *volatile fmt = FMT;
 
-int main ()
+int main (void)
 {
   int c = a;
   int d = b;
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr79800.c b/gcc/testsuite/gcc.dg/tree-ssa/pr79800.c
index 030e276..aa5b19d 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/pr79800.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr79800.c
@@ -23,7 +23,7 @@ void f (int p)
 
 volatile int i = -1;
 
-int main ()
+int main (void)
 {
   f (i);
 
diff --git a/gcc/testsuite/gcc.dg/uninit-10-O0.c b/gcc/testsuite/gcc.dg/uninit-10-O0.c
index f761ac9..69ef364 100644
--- a/gcc/testsuite/gcc.dg/uninit-10-O0.c
+++ b/gcc/testsuite/gcc.dg/uninit-10-O0.c
@@ -41,8 +41,7 @@ extern int have_error;
 extern char *strchr (__const char *__s, int __c) __attribute__ ((__pure__));
 
 void
-validate_insn_alternatives (d)
-     struct data *d;
+validate_insn_alternatives (struct data *d)
 {
   int n = 0, start;
 
diff --git a/gcc/testsuite/gcc.dg/uninit-10.c b/gcc/testsuite/gcc.dg/uninit-10.c
index 0d62020..16931b8 100644
--- a/gcc/testsuite/gcc.dg/uninit-10.c
+++ b/gcc/testsuite/gcc.dg/uninit-10.c
@@ -41,8 +41,7 @@ extern int have_error;
 extern char *strchr (__const char *__s, int __c) __attribute__ ((__pure__));
 
 void
-validate_insn_alternatives (d)
-     struct data *d;
+validate_insn_alternatives (struct data *d)
 {
   int n = 0, start;
 
diff --git a/gcc/testsuite/gcc.dg/uninit-A-O0.c b/gcc/testsuite/gcc.dg/uninit-A-O0.c
index 6937691..6c80868 100644
--- a/gcc/testsuite/gcc.dg/uninit-A-O0.c
+++ b/gcc/testsuite/gcc.dg/uninit-A-O0.c
@@ -45,8 +45,7 @@ tree resolve_and_layout (tree, tree);
 tree lookup_field_wrapper (tree, tree);
 
 void
-qualify_ambiguous_name (id)
-     tree id;
+qualify_ambiguous_name (tree id)
 {
   tree qual, qual_wfl, decl;
   tree name;	 /* { dg-bogus "name" "uninitialized variable warning" } */
diff --git a/gcc/testsuite/gcc.dg/uninit-A.c b/gcc/testsuite/gcc.dg/uninit-A.c
index 28f7fe9..a11918c 100644
--- a/gcc/testsuite/gcc.dg/uninit-A.c
+++ b/gcc/testsuite/gcc.dg/uninit-A.c
@@ -45,8 +45,7 @@ tree resolve_and_layout (tree, tree);
 tree lookup_field_wrapper (tree, tree);
 
 void
-qualify_ambiguous_name (id)
-     tree id;
+qualify_ambiguous_name (tree id)
 {
   tree qual, qual_wfl, decl;
   tree name;	 /* { dg-bogus "name" "uninitialized variable warning" } */
diff --git a/gcc/testsuite/gcc.dg/unused-1.c b/gcc/testsuite/gcc.dg/unused-1.c
index 8db7c2c..790254d 100644
--- a/gcc/testsuite/gcc.dg/unused-1.c
+++ b/gcc/testsuite/gcc.dg/unused-1.c
@@ -9,3 +9,5 @@ f(c)
 {
   return 0;
 }
+
+/* { dg-prune-output "\\\[-Wstrict-prototypes]" } */
diff --git a/gcc/testsuite/gcc.dg/unused-6-WallWextra.c b/gcc/testsuite/gcc.dg/unused-6-WallWextra.c
index d2d80be..2d66bc5 100644
--- a/gcc/testsuite/gcc.dg/unused-6-WallWextra.c
+++ b/gcc/testsuite/gcc.dg/unused-6-WallWextra.c
@@ -5,7 +5,7 @@ static int t(int i) /* { dg-warning "unused parameter" "unused parameter warning
 {
   return 0;
 }
-int tt()
+int tt(void)
 {
   return t(0);
 }
diff --git a/gcc/testsuite/gcc.dg/unused-6-no.c b/gcc/testsuite/gcc.dg/unused-6-no.c
index 0923cfb..acb8b31 100644
--- a/gcc/testsuite/gcc.dg/unused-6-no.c
+++ b/gcc/testsuite/gcc.dg/unused-6-no.c
@@ -5,7 +5,7 @@ static int t(int i) /* { dg-bogus "unused parameter" "unused parameter warning"
 {
   return 0;
 }
-int tt()
+int tt(void)
 {
   return t(0);
 }
diff --git a/gcc/testsuite/gcc.target/x86_64/abi/ms-sysv/ms-sysv.c b/gcc/testsuite/gcc.target/x86_64/abi/ms-sysv/ms-sysv.c
index 5fdd1e2..c0e63cf 100644
--- a/gcc/testsuite/gcc.target/x86_64/abi/ms-sysv/ms-sysv.c
+++ b/gcc/testsuite/gcc.target/x86_64/abi/ms-sysv/ms-sysv.c
@@ -133,7 +133,7 @@ struct test_data
 } test_data;
 
 static int shrink_wrap_global;
-static void __attribute((sysv_abi)) do_tests ();
+static void __attribute((sysv_abi)) do_tests (void);
 static void init_test (void *fn, const char *name,
 		       enum alignment_option alignment,
 		       enum shrink_wrap_option shrink_wrap, long ret_expected);
@@ -257,7 +257,7 @@ static const char *shrink_wrap_str[SHRINK_WRAP_COUNT] =
   "", "shrink-wrap fast path", "shrink-wrap slow path"
 };
 
-static const char *test_descr ()
+static const char *test_descr (void)
 {
   static char buffer[0x400];
 
@@ -378,7 +378,7 @@ static __attribute__((ms_abi, noinline)) long do_sibcall (long arg) {
   return arg + FLAG_SIBCALL;
 }
 
-void usage ()
+void usage (void)
 {
   fprintf (stderr, "Usage: %s [-s <seed>] [-f]\n", argv0);
   exit (-1);
