re PR c++/4401 (Array subscript evaluation sometimes wrong for 64-bit architectures)

	PR c++/4401
	* c-common.c (pointer_int_sum): Moved from...
	* c-typeck.c (pointer_int_sum): ...here.
	* c-common.h (pointer_int_sum): Add prototype.

	* typeck.c (cp_pointer_int_sum): Renamed from
	pointer_int_sum, call pointer_int_sum.

	* g++.dg/opt/ptrintsum1.C: New test.

From-SVN: r49916

8 files changed, 152 insertions, 177 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index b5f5fcd1e9c..59d8288a77a 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,12 @@
 2002-02-20  Jakub Jelinek  <jakub@redhat.com>
 
+	PR c++/4401
+	* c-common.c (pointer_int_sum): Moved from...
+	* c-typeck.c (pointer_int_sum): ...here.
+	* c-common.h (pointer_int_sum): Add prototype.
+
+2002-02-20  Jakub Jelinek  <jakub@redhat.com>
+
 	PR c++/5713
 	* c-decl.c (duplicate_decls): Return 0 if issued error about
 	redeclaration.
diff --git a/gcc/c-common.c b/gcc/c-common.c
index b2bdf50ef28..dfdacca3c55 100644
--- a/gcc/c-common.c
+++ b/gcc/c-common.c
@@ -1982,6 +1982,107 @@ shorten_compare (op0_ptr, op1_ptr, restype_ptr, rescode_ptr)
   return 0;
 }
 
+/* Return a tree for the sum or difference (RESULTCODE says which)
+   of pointer PTROP and integer INTOP.  */
+
+tree
+pointer_int_sum (resultcode, ptrop, intop)
+     enum tree_code resultcode;
+     tree ptrop, intop;
+{
+  tree size_exp;
+
+  tree result;
+  tree folded;
+
+  /* The result is a pointer of the same type that is being added.  */
+
+  tree result_type = TREE_TYPE (ptrop);
+
+  if (TREE_CODE (TREE_TYPE (result_type)) == VOID_TYPE)
+    {
+      if (pedantic || warn_pointer_arith)
+	pedwarn ("pointer of type `void *' used in arithmetic");
+      size_exp = integer_one_node;
+    }
+  else if (TREE_CODE (TREE_TYPE (result_type)) == FUNCTION_TYPE)
+    {
+      if (pedantic || warn_pointer_arith)
+	pedwarn ("pointer to a function used in arithmetic");
+      size_exp = integer_one_node;
+    }
+  else if (TREE_CODE (TREE_TYPE (result_type)) == METHOD_TYPE)
+    {
+      if (pedantic || warn_pointer_arith)
+	pedwarn ("pointer to member function used in arithmetic");
+      size_exp = integer_one_node;
+    }
+  else if (TREE_CODE (TREE_TYPE (result_type)) == OFFSET_TYPE)
+    {
+      if (pedantic || warn_pointer_arith)
+	pedwarn ("pointer to a member used in arithmetic");
+      size_exp = integer_one_node;
+    }
+  else
+    size_exp = size_in_bytes (TREE_TYPE (result_type));
+
+  /* If what we are about to multiply by the size of the elements
+     contains a constant term, apply distributive law
+     and multiply that constant term separately.
+     This helps produce common subexpressions.  */
+
+  if ((TREE_CODE (intop) == PLUS_EXPR || TREE_CODE (intop) == MINUS_EXPR)
+      && ! TREE_CONSTANT (intop)
+      && TREE_CONSTANT (TREE_OPERAND (intop, 1))
+      && TREE_CONSTANT (size_exp)
+      /* If the constant comes from pointer subtraction,
+	 skip this optimization--it would cause an error.  */
+      && TREE_CODE (TREE_TYPE (TREE_OPERAND (intop, 0))) == INTEGER_TYPE
+      /* If the constant is unsigned, and smaller than the pointer size,
+	 then we must skip this optimization.  This is because it could cause
+	 an overflow error if the constant is negative but INTOP is not.  */
+      && (! TREE_UNSIGNED (TREE_TYPE (intop))
+	  || (TYPE_PRECISION (TREE_TYPE (intop))
+	      == TYPE_PRECISION (TREE_TYPE (ptrop)))))
+    {
+      enum tree_code subcode = resultcode;
+      tree int_type = TREE_TYPE (intop);
+      if (TREE_CODE (intop) == MINUS_EXPR)
+	subcode = (subcode == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR);
+      /* Convert both subexpression types to the type of intop,
+	 because weird cases involving pointer arithmetic
+	 can result in a sum or difference with different type args.  */
+      ptrop = build_binary_op (subcode, ptrop,
+			       convert (int_type, TREE_OPERAND (intop, 1)), 1);
+      intop = convert (int_type, TREE_OPERAND (intop, 0));
+    }
+
+  /* Convert the integer argument to a type the same size as sizetype
+     so the multiply won't overflow spuriously.  */
+
+  if (TYPE_PRECISION (TREE_TYPE (intop)) != TYPE_PRECISION (sizetype)
+      || TREE_UNSIGNED (TREE_TYPE (intop)) != TREE_UNSIGNED (sizetype))
+    intop = convert (type_for_size (TYPE_PRECISION (sizetype), 
+				    TREE_UNSIGNED (sizetype)), intop);
+
+  /* Replace the integer argument with a suitable product by the object size.
+     Do this multiplication as signed, then convert to the appropriate
+     pointer type (actually unsigned integral).  */
+
+  intop = convert (result_type,
+		   build_binary_op (MULT_EXPR, intop,
+				    convert (TREE_TYPE (intop), size_exp), 1));
+
+  /* Create the sum or difference.  */
+
+  result = build (resultcode, result_type, ptrop, intop);
+
+  folded = fold (result);
+  if (folded == result)
+    TREE_CONSTANT (folded) = TREE_CONSTANT (ptrop) & TREE_CONSTANT (intop);
+  return folded;
+}
+
 /* Prepare expr to be an argument of a TRUTH_NOT_EXPR,
    or validate its data type for an `if' or `while' statement or ?..: exp.
 
diff --git a/gcc/c-common.h b/gcc/c-common.h
index c90cbfb076b..9bb2d1ac233 100644
--- a/gcc/c-common.h
+++ b/gcc/c-common.h
@@ -538,6 +538,7 @@ extern char *get_directive_line			PARAMS ((void));
    and, if so, perhaps change them both back to their original type.  */
 extern tree shorten_compare			PARAMS ((tree *, tree *, tree *, enum tree_code *));
 
+extern tree pointer_int_sum			PARAMS ((enum tree_code, tree, tree));
 extern unsigned int min_precision		PARAMS ((tree, int));
 
 /* Add qualifiers to a type, in the fashion for C.  */
diff --git a/gcc/c-typeck.c b/gcc/c-typeck.c
index dd8abdd11f7..4ee7cb3b697 100644
--- a/gcc/c-typeck.c
+++ b/gcc/c-typeck.c
@@ -58,7 +58,6 @@ static tree decl_constant_value_for_broken_optimization PARAMS ((tree));
 static tree default_function_array_conversion	PARAMS ((tree));
 static tree lookup_field		PARAMS ((tree, tree));
 static tree convert_arguments		PARAMS ((tree, tree, tree, tree));
-static tree pointer_int_sum		PARAMS ((enum tree_code, tree, tree));
 static tree pointer_diff		PARAMS ((tree, tree));
 static tree unary_complex_lvalue	PARAMS ((enum tree_code, tree, int));
 static void pedantic_lvalue_warning	PARAMS ((enum tree_code));
@@ -2637,95 +2636,6 @@ build_binary_op (code, orig_op0, orig_op1, convert_p)
   }
 }
 
-/* Return a tree for the sum or difference (RESULTCODE says which)
-   of pointer PTROP and integer INTOP.  */
-
-static tree
-pointer_int_sum (resultcode, ptrop, intop)
-     enum tree_code resultcode;
-     tree ptrop, intop;
-{
-  tree size_exp;
-
-  tree result;
-  tree folded;
-
-  /* The result is a pointer of the same type that is being added.  */
-
-  tree result_type = TREE_TYPE (ptrop);
-
-  if (TREE_CODE (TREE_TYPE (result_type)) == VOID_TYPE)
-    {
-      if (pedantic || warn_pointer_arith)
-	pedwarn ("pointer of type `void *' used in arithmetic");
-      size_exp = integer_one_node;
-    }
-  else if (TREE_CODE (TREE_TYPE (result_type)) == FUNCTION_TYPE)
-    {
-      if (pedantic || warn_pointer_arith)
-	pedwarn ("pointer to a function used in arithmetic");
-      size_exp = integer_one_node;
-    }
-  else
-    size_exp = c_size_in_bytes (TREE_TYPE (result_type));
-
-  /* If what we are about to multiply by the size of the elements
-     contains a constant term, apply distributive law
-     and multiply that constant term separately.
-     This helps produce common subexpressions.  */
-
-  if ((TREE_CODE (intop) == PLUS_EXPR || TREE_CODE (intop) == MINUS_EXPR)
-      && ! TREE_CONSTANT (intop)
-      && TREE_CONSTANT (TREE_OPERAND (intop, 1))
-      && TREE_CONSTANT (size_exp)
-      /* If the constant comes from pointer subtraction,
-	 skip this optimization--it would cause an error.  */
-      && TREE_CODE (TREE_TYPE (TREE_OPERAND (intop, 0))) == INTEGER_TYPE
-      /* If the constant is unsigned, and smaller than the pointer size,
-	 then we must skip this optimization.  This is because it could cause
-	 an overflow error if the constant is negative but INTOP is not.  */
-      && (! TREE_UNSIGNED (TREE_TYPE (intop))
-	  || (TYPE_PRECISION (TREE_TYPE (intop))
-	      == TYPE_PRECISION (TREE_TYPE (ptrop)))))
-    {
-      enum tree_code subcode = resultcode;
-      tree int_type = TREE_TYPE (intop);
-      if (TREE_CODE (intop) == MINUS_EXPR)
-	subcode = (subcode == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR);
-      /* Convert both subexpression types to the type of intop,
-	 because weird cases involving pointer arithmetic
-	 can result in a sum or difference with different type args.  */
-      ptrop = build_binary_op (subcode, ptrop,
-			       convert (int_type, TREE_OPERAND (intop, 1)), 1);
-      intop = convert (int_type, TREE_OPERAND (intop, 0));
-    }
-
-  /* Convert the integer argument to a type the same size as sizetype
-     so the multiply won't overflow spuriously.  */
-
-  if (TYPE_PRECISION (TREE_TYPE (intop)) != TYPE_PRECISION (sizetype)
-      || TREE_UNSIGNED (TREE_TYPE (intop)) != TREE_UNSIGNED (sizetype))
-    intop = convert (type_for_size (TYPE_PRECISION (sizetype), 
-				    TREE_UNSIGNED (sizetype)), intop);
-
-  /* Replace the integer argument with a suitable product by the object size.
-     Do this multiplication as signed, then convert to the appropriate
-     pointer type (actually unsigned integral).  */
-
-  intop = convert (result_type,
-		   build_binary_op (MULT_EXPR, intop,
-				    convert (TREE_TYPE (intop), size_exp), 1));
-
-  /* Create the sum or difference.  */
-
-  result = build (resultcode, result_type, ptrop, intop);
-
-  folded = fold (result);
-  if (folded == result)
-    TREE_CONSTANT (folded) = TREE_CONSTANT (ptrop) & TREE_CONSTANT (intop);
-  return folded;
-}
-
 /* Return a tree for the difference of pointers OP0 and OP1.
    The resulting tree has type int.  */
 
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 97591842633..b4a5b0bcf24 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,5 +1,10 @@
 2002-02-20  Jakub Jelinek  <jakub@redhat.com>
 
+	* typeck.c (cp_pointer_int_sum): Renamed from
+	pointer_int_sum, call pointer_int_sum.
+
+2002-02-20  Jakub Jelinek  <jakub@redhat.com>
+
 	* decl.c (duplicate_decls): Return 0 if issued error about
 	redeclaration.
 
diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c
index 62d17a8cfd9..6ca524233d8 100644
--- a/gcc/cp/typeck.c
+++ b/gcc/cp/typeck.c
@@ -45,7 +45,7 @@ Boston, MA 02111-1307, USA.  */
 
 static tree convert_for_assignment PARAMS ((tree, tree, const char *, tree,
 					  int));
-static tree pointer_int_sum PARAMS ((enum tree_code, tree, tree));
+static tree cp_pointer_int_sum PARAMS ((enum tree_code, tree, tree));
 static tree rationalize_conditional_expr PARAMS ((enum tree_code, tree));
 static int comp_target_parms PARAMS ((tree, tree));
 static int comp_ptr_ttypes_real PARAMS ((tree, tree, int));
@@ -3452,9 +3452,9 @@ build_binary_op (code, orig_op0, orig_op1, convert_p)
     case PLUS_EXPR:
       /* Handle the pointer + int case.  */
       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
-	return pointer_int_sum (PLUS_EXPR, op0, op1);
+	return cp_pointer_int_sum (PLUS_EXPR, op0, op1);
       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
-	return pointer_int_sum (PLUS_EXPR, op1, op0);
+	return cp_pointer_int_sum (PLUS_EXPR, op1, op0);
       else
 	common = 1;
       break;
@@ -3467,7 +3467,7 @@ build_binary_op (code, orig_op0, orig_op1, convert_p)
 	return pointer_diff (op0, op1, common_type (type0, type1));
       /* Handle pointer minus int.  Just like pointer plus int.  */
       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
-	return pointer_int_sum (MINUS_EXPR, op0, op1);
+	return cp_pointer_int_sum (MINUS_EXPR, op0, op1);
       else
 	common = 1;
       break;
@@ -4072,94 +4072,14 @@ build_binary_op (code, orig_op0, orig_op1, convert_p)
    of pointer PTROP and integer INTOP.  */
 
 static tree
-pointer_int_sum (resultcode, ptrop, intop)
+cp_pointer_int_sum (resultcode, ptrop, intop)
      enum tree_code resultcode;
      register tree ptrop, intop;
 {
-  tree size_exp;
-
-  register tree result;
-  register tree folded = fold (intop);
-
-  /* The result is a pointer of the same type that is being added.  */
-
-  register tree result_type = TREE_TYPE (ptrop);
-
-  if (!complete_type_or_else (result_type, ptrop))
+  if (!complete_type_or_else (TREE_TYPE (ptrop), ptrop))
     return error_mark_node;
 
-  if (TREE_CODE (TREE_TYPE (result_type)) == VOID_TYPE)
-    {
-      if (pedantic || warn_pointer_arith)
-	pedwarn ("ISO C++ forbids using pointer of type `void *' in pointer arithmetic");
-      size_exp = integer_one_node;
-    }
-  else if (TREE_CODE (TREE_TYPE (result_type)) == FUNCTION_TYPE)
-    {
-      if (pedantic || warn_pointer_arith)
-	pedwarn ("ISO C++ forbids using a pointer-to-function in pointer arithmetic");
-      size_exp = integer_one_node;
-    }
-  else if (TREE_CODE (TREE_TYPE (result_type)) == METHOD_TYPE)
-    {
-      if (pedantic || warn_pointer_arith)
-	pedwarn ("ISO C++ forbids using a pointer to member function in pointer arithmetic");
-      size_exp = integer_one_node;
-    }
-  else if (TREE_CODE (TREE_TYPE (result_type)) == OFFSET_TYPE)
-    {
-      if (pedantic || warn_pointer_arith)
-	pedwarn ("ISO C++ forbids using pointer to a member in pointer arithmetic");
-      size_exp = integer_one_node;
-    }
-  else
-    size_exp = size_in_bytes (complete_type (TREE_TYPE (result_type)));
-
-  /* Needed to make OOPS V2R3 work.  */
-  intop = folded;
-  if (integer_zerop (intop))
-    return ptrop;
-
-  /* If what we are about to multiply by the size of the elements
-     contains a constant term, apply distributive law
-     and multiply that constant term separately.
-     This helps produce common subexpressions.  */
-
-  if ((TREE_CODE (intop) == PLUS_EXPR || TREE_CODE (intop) == MINUS_EXPR)
-      && ! TREE_CONSTANT (intop)
-      && TREE_CONSTANT (TREE_OPERAND (intop, 1))
-      && TREE_CONSTANT (size_exp))
-    {
-      enum tree_code subcode = resultcode;
-      if (TREE_CODE (intop) == MINUS_EXPR)
-	subcode = (subcode == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR);
-      ptrop = cp_build_binary_op (subcode, ptrop, TREE_OPERAND (intop, 1));
-      intop = TREE_OPERAND (intop, 0);
-    }
-
-  /* Convert the integer argument to a type the same size as sizetype
-     so the multiply won't overflow spuriously.  */
-
-  if (TYPE_PRECISION (TREE_TYPE (intop)) != TYPE_PRECISION (sizetype))
-    intop = cp_convert (type_for_size (TYPE_PRECISION (sizetype), 0), intop);
-
-  /* Replace the integer argument with a suitable product by the object size.
-     Do this multiplication as signed, then convert to the appropriate
-     pointer type (actually unsigned integral).  */
-
-  intop = cp_convert (result_type,
-		      cp_build_binary_op (MULT_EXPR, intop,
-					  cp_convert (TREE_TYPE (intop),
-						      size_exp)));
-
-  /* Create the sum or difference.  */
-
-  result = build (resultcode, result_type, ptrop, intop);
-
-  folded = fold (result);
-  if (folded == result)
-    TREE_CONSTANT (folded) = TREE_CONSTANT (ptrop) & TREE_CONSTANT (intop);
-  return folded;
+  return pointer_int_sum (resultcode, ptrop, fold (intop));
 }
 
 /* Return a tree for the difference of pointers OP0 and OP1.
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 65b5ecbb594..ebf920fc0f8 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -6,6 +6,8 @@
 
 	* gcc.dg/noncompile/20020220-1.c: New test.
 
+	* g++.dg/opt/ptrintsum1.C: New test.
+
 2002-02-17  Jakub Jelinek  <jakub@redhat.com>
 
 	* gcc.c-torture/execute/20020216-1.c: New test.
diff --git a/gcc/testsuite/g++.dg/opt/ptrintsum1.C b/gcc/testsuite/g++.dg/opt/ptrintsum1.C
new file mode 100644
index 00000000000..a6a3c9727db
--- /dev/null
+++ b/gcc/testsuite/g++.dg/opt/ptrintsum1.C
@@ -0,0 +1,29 @@
+// PR c++/4401
+// This testcase was miscompiled on 64-bit platforms, resulting to
+// operating on a[0x100000000] instead of a[0].
+// { dg-do run }
+// { dg-options "-O2" }
+
+char *a;
+char b[] = "AAAA";
+
+extern "C" void abort (void);
+extern "C" void exit (int);
+
+void foo (void)
+{
+  unsigned int i, j;
+
+  i = 2;
+  j = 3;
+  a[i + 1 - j] += i;
+}
+
+int main (void)
+{
+  a = b;
+  foo ();
+  if (b[0] != 'A' + 2)
+    abort ();
+  exit (0);
+}