re PR tree-optimization/43236 (-ftree-loop-distribution produces wrong code in…

re PR tree-optimization/43236 (-ftree-loop-distribution produces wrong code in reload1.c:delete_output_reload(), bootstrap fails)

        PR tree-optimization/43236
        * tree-loop-distribution.c (generate_memset_zero): Fix off-by-one
        error in calculation of base address in reverse iteration case.
        (generate_builtin): Take number of latch executions if the statement
        is in the latch.
    
        * gcc.c-torture/execute/pr43236.c: New.

From-SVN: r157339

gcc/ChangeLog

+2010-03-10  Alexander Monakov  <amonakov@ispras.ru>
+
+	PR tree-optimization/43236
+	* tree-loop-distribution.c (generate_memset_zero): Fix off-by-one
+	error in calculation of base address in reverse iteration case.
+	(generate_builtin): Take number of latch executions if the statement
+	is in the latch.
+
 2010-03-10  Andrey Belevantsev  <abel@ispras.ru>
 
 	PR middle-end/42859

gcc/testsuite/ChangeLog

+2010-03-10  Alexander Monakov  <amonakov@ispras.ru>
+
+	PR tree-optimization/43236
+	* gcc.c-torture/execute/pr43236.c: New test.
+
 2010-03-10  Andrey Belevantsev  <abel@ispras.ru>
 
 	PR middle-end/42859

gcc/testsuite/gcc.c-torture/execute/pr43236.c

+/* { dg-options "-ftree-loop-distribution" } */
+extern void abort(void);
+extern void *memset(void *s, int c, __SIZE_TYPE__ n);
+extern int memcmp(const void *s1, const void *s2, __SIZE_TYPE__ n);
+/*extern int printf(const char *format, ...);*/
+
+int main()
+{
+  char A[30], B[30], C[30];
+  int i;
+
+  /* prepare arrays */
+  memset(A, 1, 30);
+  memset(B, 1, 30);
+
+  for (i = 20; i-- > 10;) {
+    A[i] = 0;
+    B[i] = 0;
+  }
+
+  /* expected result */
+  memset(C, 1, 30);
+  memset(C + 10, 0, 10);
+
+  /* show result */
+/*  for (i = 0; i < 30; i++)
+    printf("%d %d %d\n", A[i], B[i], C[i]); */
+
+  /* compare results */
+  if (memcmp(A, C, 30) || memcmp(B, C, 30)) abort();
+  return 0;
+}

gcc/tree-loop-distribution.c

@@ -285,6 +285,8 @@ generate_memset_zero (gimple stmt, tree op0, tree nb_iter,
       addr_base = fold_convert_loc (loc, sizetype, addr_base);
       addr_base = size_binop_loc (loc, MINUS_EXPR, addr_base,
 				  fold_convert_loc (loc, sizetype, nb_bytes));
+      addr_base = size_binop_loc (loc, PLUS_EXPR, addr_base,
+				  TYPE_SIZE_UNIT (TREE_TYPE (op0)));
       addr_base = fold_build2_loc (loc, POINTER_PLUS_EXPR,
 				   TREE_TYPE (DR_BASE_ADDRESS (dr)),
 				   DR_BASE_ADDRESS (dr), addr_base);
@@ -389,6 +391,8 @@ generate_builtin (struct loop *loop, bitmap partition, bool copy_p)
 		goto end;
 
 	      write = stmt;
+	      if (bb == loop->latch)
+		nb_iter = number_of_latch_executions (loop);
 	    }
 	}
     }