re PR c/82765 (ICE at -Os on valid code on x86_64-linux-gnu: in tree_to_shwi, at tree.c:6611)

2017-11-02  Richard Biener  <rguenther@suse.de>

	PR middle-end/82765
	* varasm.c (decode_addr_const): Make offset HOST_WIDE_INT.
	Truncate ARRAY_REF index and element size.

	* gcc.dg/pr82765.c: New testcase.

From-SVN: r254337

gcc/ChangeLog

+2017-11-02  Richard Biener  <rguenther@suse.de>
+
+	PR middle-end/82765
+	* varasm.c (decode_addr_const): Make offset HOST_WIDE_INT.
+	Truncate ARRAY_REF index and element size.
+
 2017-11-01  Palmer Dabbelt  <palmer@dabbelt.com>
 
 	* doc/invoke.texi (RISC-V Options): Use "@minus{}2 GB", not "-2 GB".

gcc/testsuite/ChangeLog

+2017-11-02  Richard Biener  <rguenther@suse.de>
+
+	PR middle-end/82765
+	* gcc.dg/pr82765.c: New testcase.
+
 2017-11-02  Tom de Vries  <tom@codesourcery.com>
 
 	* gfortran.dg/implied_do_io_1.f90: Fix scan-tree-dump-times pattern.

gcc/testsuite/gcc.dg/pr82765.c

+/* { dg-do compile } */
+/* { dg-options "-Os -w" } */
+
+int a[1][1];
+int main() { int *b[] = {a, a[1820408606019012862278468], a, a, a}; }

gcc/varasm.c

@@ -2879,7 +2879,7 @@ static void
 decode_addr_const (tree exp, struct addr_const *value)
 {
   tree target = TREE_OPERAND (exp, 0);
-  int offset = 0;
+  HOST_WIDE_INT offset = 0;
   rtx x;
 
   while (1)
@@ -2893,8 +2893,9 @@ decode_addr_const (tree exp, struct addr_const *value)
       else if (TREE_CODE (target) == ARRAY_REF
 	       || TREE_CODE (target) == ARRAY_RANGE_REF)
 	{
-	  offset += (tree_to_uhwi (TYPE_SIZE_UNIT (TREE_TYPE (target)))
-		     * tree_to_shwi (TREE_OPERAND (target, 1)));
+	  /* Truncate big offset.  */
+	  offset += (TREE_INT_CST_LOW (TYPE_SIZE_UNIT (TREE_TYPE (target)))
+		     * TREE_INT_CST_LOW (TREE_OPERAND (target, 1)));
 	  target = TREE_OPERAND (target, 0);
 	}
       else if (TREE_CODE (target) == MEM_REF