re PR c/21438 (Warning about division by zero depends on lexical form)

2007-03-14  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>

	PR c/21438
	* c-common.h (warn_for_div_by_zero): Declare.
	* c-common.c (warn_for_div_by_zero): Define.
	* c-typeck.c (build_binary_op): Call warn_for_div_zero instead of
	warning.
cp/
	* typeck.c (build_binary_op): Call warn_for_div_zero instead of
	warning.

From-SVN: r122925

gcc/ChangeLog

+2007-03-14  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>
+
+	PR c/21438
+	* c-common.h (warn_for_div_by_zero): Declare.
+	* c-common.c (warn_for_div_by_zero): Define.
+	* c-typeck.c (build_binary_op): Call warn_for_div_zero instead of
+	warning.
+
 2007-03-14  Richard Sandiford  <richard@codesourcery.com>
 
 	* Makefile.in (PREPROCESSOR_DEFINES): Add directory terminators

gcc/c-common.c

@@ -7032,4 +7032,17 @@ c_build_cdtor_fns (void)
 struct gcc_targetcm targetcm = TARGETCM_INITIALIZER;
 #endif
 
+/* Warn for division by zero according to the value of DIVISOR.  */
+
+void
+warn_for_div_by_zero (tree divisor)
+{
+  /* If DIVISOR is zero, and has integral type, issue a warning about
+     division by zero.  Do not issue a warning if DIVISOR has a
+     floating-point type, since we consider 0.0/0.0 a valid way of
+     generating a NaN.  */
+  if (skip_evaluation == 0 && integer_zerop (divisor))
+    warning (OPT_Wdiv_by_zero, "division by zero");
+}
+
 #include "gt-c-common.h"

gcc/c-common.h

@@ -871,6 +871,7 @@ extern void warn_array_subscript_with_type_char (tree);
 extern void warn_about_parentheses (enum tree_code, enum tree_code,
 				    enum tree_code);
 extern void warn_for_unused_label (tree label);
+extern void warn_for_div_by_zero (tree divisor);
 
 
 /* In c-gimplify.c  */

gcc/c-typeck.c

@@ -7848,10 +7848,7 @@ build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
     case FLOOR_DIV_EXPR:
     case ROUND_DIV_EXPR:
     case EXACT_DIV_EXPR:
-      /* Floating point division by zero is a legitimate way to obtain
-	 infinities and NaNs.  */
-      if (skip_evaluation == 0 && integer_zerop (op1))
-	warning (OPT_Wdiv_by_zero, "division by zero");
+      warn_for_div_by_zero (op1);
 
       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
 	   || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
@@ -7891,8 +7888,7 @@ build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
 
     case TRUNC_MOD_EXPR:
     case FLOOR_MOD_EXPR:
-      if (skip_evaluation == 0 && integer_zerop (op1))
-	warning (OPT_Wdiv_by_zero, "division by zero");
+      warn_for_div_by_zero (op1);
 
       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
 	{

gcc/cp/ChangeLog

+2007-03-14  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>
+
+	PR c/21438
+	* typeck.c (build_binary_op): Call warn_for_div_zero instead of
+	warning.
+	
 2007-03-13  Alexandre Oliva  <aoliva@redhat.com>
 
 	* cp/repo.c (init_repo): Initialize random_seed saved options.

gcc/cp/typeck.c

@@ -3169,10 +3169,7 @@ build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
 	{
 	  enum tree_code tcode0 = code0, tcode1 = code1;
 
-	  if (TREE_CODE (op1) == INTEGER_CST && integer_zerop (op1))
-	    warning (OPT_Wdiv_by_zero, "division by zero in %<%E / 0%>", op0);
-	  else if (TREE_CODE (op1) == REAL_CST && real_zerop (op1))
-	    warning (OPT_Wdiv_by_zero, "division by zero in %<%E / 0.%>", op0);
+	  warn_for_div_by_zero (op1);
 
 	  if (tcode0 == COMPLEX_TYPE || tcode0 == VECTOR_TYPE)
 	    tcode0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
@@ -3206,10 +3203,7 @@ build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
 
     case TRUNC_MOD_EXPR:
     case FLOOR_MOD_EXPR:
-      if (code1 == INTEGER_TYPE && integer_zerop (op1))
-	warning (OPT_Wdiv_by_zero, "division by zero in %<%E %% 0%>", op0);
-      else if (code1 == REAL_TYPE && real_zerop (op1))
-	warning (OPT_Wdiv_by_zero, "division by zero in %<%E %% 0.%>", op0);
+      warn_for_div_by_zero (op1);
 
       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
 	{