c: Less warnings for parameters declared as arrays [PR98536]

To avoid false positivies, tune the warnings for parameters declared
as arrays with size expressions.  Do not warn when more bounds are
specified in the declaration than before.

	PR c/98536

gcc/c-family/:
	* c-warn.cc (warn_parm_array_mismatch): Do not warn if more
	bounds are specified.

gcc/testsuite:
	* gcc.dg/Wvla-parameter-4.c: Adapt test.
	* gcc.dg/attr-access-2.c: Adapt test.

3 files changed, 3 insertions, 32 deletions

diff --git a/gcc/c-family/c-warn.cc b/gcc/c-family/c-warn.cc
index d4d62c4..b7c5d7c 100644
--- a/gcc/c-family/c-warn.cc
+++ b/gcc/c-family/c-warn.cc
@@ -3599,23 +3599,13 @@ warn_parm_array_mismatch (location_t origloc, tree fndecl, tree newparms)
 	      continue;
 	    }
 
-	  if (newunspec != curunspec)
+	  if (newunspec > curunspec)
 	    {
 	      location_t warnloc = newloc, noteloc = origloc;
 	      const char *warnparmstr = newparmstr.c_str ();
 	      const char *noteparmstr = curparmstr.c_str ();
 	      unsigned warnunspec = newunspec, noteunspec = curunspec;
 
-	      if (newunspec < curunspec)
-		{
-		  /* If the new declaration has fewer unspecified bounds
-		     point the warning to the previous declaration to make
-		     it clear that that's the one to change.  Otherwise,
-		     point it to the new decl.  */
-		  std::swap (warnloc, noteloc);
-		  std::swap (warnparmstr, noteparmstr);
-		  std::swap (warnunspec, noteunspec);
-		}
 	      if (warning_n (warnloc, OPT_Wvla_parameter, warnunspec,
 			     "argument %u of type %s declared with "
 			     "%u unspecified variable bound",
@@ -3643,14 +3633,10 @@ warn_parm_array_mismatch (location_t origloc, tree fndecl, tree newparms)
 	}
 
       /* Iterate over the lists of VLA variable bounds, comparing each
-	 pair for equality, and diagnosing mismatches.  The case of
-	 the lists having different lengths is handled above so at
-	 this point they do .  */
-      for (tree newvbl = newa->size, curvbl = cura->size; newvbl;
+	 pair for equality, and diagnosing mismatches.  */
+      for (tree newvbl = newa->size, curvbl = cura->size; newvbl && curvbl;
 	   newvbl = TREE_CHAIN (newvbl), curvbl = TREE_CHAIN (curvbl))
 	{
-	  gcc_assert (curvbl);
-
 	  tree newpos = TREE_PURPOSE (newvbl);
 	  tree curpos = TREE_PURPOSE (curvbl);
 
diff --git a/gcc/testsuite/gcc.dg/Wvla-parameter-4.c b/gcc/testsuite/gcc.dg/Wvla-parameter-4.c
index 599ad19..f35faea 100644
--- a/gcc/testsuite/gcc.dg/Wvla-parameter-4.c
+++ b/gcc/testsuite/gcc.dg/Wvla-parameter-4.c
@@ -12,11 +12,6 @@ typedef int IA3[3];
 /* Verify the warning points to the declaration with more unspecified
    bounds, guiding the user to specify them rather than making them all
    unspecified.  */
-void* f_pIA3ax (IA3 *x[*]);             // { dg-warning "argument 1 of type 'int \\\(\\\*\\\[\\\*]\\\)\\\[3]' .aka '\[^\n\r\}\]+'. declared with 1 unspecified variable bound" }
-void* f_pIA3ax (IA3 *x[*]);
-void* f_pIA3ax (IA3 *x[n]);             // { dg-message "subsequently declared as 'int \\\(\\\*\\\[n]\\\)\\\[3]' with 0 unspecified variable bounds" "note" }
-void* f_pIA3ax (IA3 *x[n]) { return x; }
-
 
 void* f_pIA3an (IA3 *x[n]);              // { dg-message "previously declared as 'int \\\(\\\*\\\[n]\\\)\\\[3]' with 0 unspecified variable bounds" "note" }
 void* f_pIA3an (IA3 *x[n]);
diff --git a/gcc/testsuite/gcc.dg/attr-access-2.c b/gcc/testsuite/gcc.dg/attr-access-2.c
index 76baddf..616b7a9 100644
--- a/gcc/testsuite/gcc.dg/attr-access-2.c
+++ b/gcc/testsuite/gcc.dg/attr-access-2.c
@@ -60,16 +60,6 @@ RW (2, 1) void f10 (int n, char a[n])   // { dg-warning "attribute 'access *\\\(
                                         // { dg-warning "argument 2 of type 'char\\\[n]' declared as a variable length array"  "" { target *-*-* } .-1 }
 { (void)&n; (void)&a; }
 
-
-/* The following is diagnosed to point out declarations with the T[*]
-   form in headers where specifying the bound is just as important as
-   in the definition (to detect bugs).  */
-          void f11 (int, char[*]);      // { dg-warning "argument 2 of type 'char\\\[\\\*\\\]' declared with 1 unspecified variable bound" }
-          void f11 (int m, char a[m]);  // { dg-message "subsequently declared as 'char\\\[m]' with 0 unspecified variable bounds" "note" }
-RW (2, 1) void f11 (int n, char arr[n]) // { dg-message "subsequently declared as 'char\\\[n]' with 0 unspecified variable bounds" "note" }
-{ (void)&n; (void)&arr; }
-
-
 /* Verify that redeclaring a function with attribute access applying
    to an array parameter of any form is not diagnosed.  */
           void f12__ (int, int[]) RW (2, 1);