C PATCH for c/85318, missing -Wc90-c99-compat warning with for-init-loop

[Marek Polacek]

This PR reports that we are not emitting a -Wc90-c99-compat warning
for a for loop with a declaration.  This patch adds it; here we want
to use pedwarn_c90 which takes care of it.

Bootstrapped/regtested on x86_64-linux, ok for trunk?

2018-06-07  Marek Polacek  <pola...@redhat.com>

        PR c/85318
        * c-decl.c (check_for_loop_decls): Add -Wc90-c99-compat warning about
        for loop initial declarations.

        * gcc.dg/Wc90-c99-compat-10.c: New test.
        * gcc.dg/Wc90-c99-compat-11.c: New test.
        * gcc.dg/Wc90-c99-compat-12.c: New test.
        * gcc.dg/Wc90-c99-compat-9.c: New test.

diff --git gcc/c/c-decl.c gcc/c/c-decl.c
index 54f58a56cde..729187c79e9 100644
--- gcc/c/c-decl.c
+++ gcc/c/c-decl.c
@@ -9608,6 +9608,10 @@ check_for_loop_decls (location_t loc, bool 
turn_off_iso_c99_error)
        }
       return NULL_TREE;
     }
+  else
+    pedwarn_c90 (loc, OPT_Wpedantic, "ISO C90 does not support %<for%> loop "
+                "initial declarations");
+
   /* C99 subclause 6.8.5 paragraph 3:
 
        [#3]  The  declaration  part  of  a for statement shall only
diff --git gcc/testsuite/gcc.dg/Wc90-c99-compat-10.c 
gcc/testsuite/gcc.dg/Wc90-c99-compat-10.c
index e69de29bb2d..c419ec52be0 100644
--- gcc/testsuite/gcc.dg/Wc90-c99-compat-10.c
+++ gcc/testsuite/gcc.dg/Wc90-c99-compat-10.c
@@ -0,0 +1,12 @@
+/* PR c/85318 */
+/* { dg-do compile } */
+/* { dg-options "-std=gnu11 -Wc90-c99-compat -pedantic-errors" } */
+
+extern void bar (int);
+
+void
+foo (int n)
+{
+  for (int i = 0; i < n; i++) /* { dg-warning "ISO C90 does not support .for. 
loop" } */
+    bar (i);
+}
diff --git gcc/testsuite/gcc.dg/Wc90-c99-compat-11.c 
gcc/testsuite/gcc.dg/Wc90-c99-compat-11.c
index e69de29bb2d..12f9d27b7ac 100644
--- gcc/testsuite/gcc.dg/Wc90-c99-compat-11.c
+++ gcc/testsuite/gcc.dg/Wc90-c99-compat-11.c
@@ -0,0 +1,12 @@
+/* PR c/85318 */
+/* { dg-do compile } */
+/* { dg-options "-std=gnu11 -Wc90-c99-compat -Wno-pedantic" } */
+
+extern void bar (int);
+
+void
+foo (int n)
+{
+  for (int i = 0; i < n; i++) /* { dg-warning "ISO C90 does not support .for. 
loop" } */
+    bar (i);
+}
diff --git gcc/testsuite/gcc.dg/Wc90-c99-compat-12.c 
gcc/testsuite/gcc.dg/Wc90-c99-compat-12.c
index e69de29bb2d..37f2e85423c 100644
--- gcc/testsuite/gcc.dg/Wc90-c99-compat-12.c
+++ gcc/testsuite/gcc.dg/Wc90-c99-compat-12.c
@@ -0,0 +1,12 @@
+/* PR c/85318 */
+/* { dg-do compile } */
+/* { dg-options "-Wpedantic" } */
+
+extern void bar (int);
+
+void
+foo (int n)
+{
+  for (int i = 0; i < n; i++) /* { dg-bogus "ISO C90 does not support .for. 
loop" } */
+    bar (i);
+}
diff --git gcc/testsuite/gcc.dg/Wc90-c99-compat-9.c 
gcc/testsuite/gcc.dg/Wc90-c99-compat-9.c
index e69de29bb2d..8bd996c8c25 100644
--- gcc/testsuite/gcc.dg/Wc90-c99-compat-9.c
+++ gcc/testsuite/gcc.dg/Wc90-c99-compat-9.c
@@ -0,0 +1,12 @@
+/* PR c/85318 */
+/* { dg-do compile } */
+/* { dg-options "-std=gnu99 -Wc90-c99-compat -pedantic-errors" } */
+
+extern void bar (int);
+
+void
+foo (int n)
+{
+  for (int i = 0; i < n; i++) /* { dg-warning "ISO C90 does not support .for. 
loop" } */
+    bar (i);
+}