[PATCH] Fix PR59471

[Richard Biener]

This fixes PR59471 by properly gimplifying

  VIEW_CONVERT_EXPR<uint8x8_t>(BIT_FIELD_REF <VIEW_CONVERT_EXPR<vector(2) 
long unsigned int>(x), 64, 0>)

to use separate stmts for the VIEW_CONVERT_EXPRs.

Bootstrap and regtest running on x86_64-unknown-linux-gnu.

Richard.

2014-01-07  Richard Biener  <rguent...@suse.de>

        PR middle-end/59471
        * gimplify.c (gimplify_expr): Gimplify register-register type
        VIEW_CONVERT_EXPRs to separate stmts.

        * gcc.dg/pr59471.c: New testcase.

Index: gcc/gimplify.c
===================================================================
*** gcc/gimplify.c      (revision 206385)
--- gcc/gimplify.c      (working copy)
*************** gimplify_expr (tree *expr_p, gimple_seq
*** 7373,7384 ****
                                        TREE_TYPE (*expr_p));
          break;
  
        case ARRAY_REF:
        case ARRAY_RANGE_REF:
        case REALPART_EXPR:
        case IMAGPART_EXPR:
        case COMPONENT_REF:
-       case VIEW_CONVERT_EXPR:
          ret = gimplify_compound_lval (expr_p, pre_p, post_p,
                                        fallback ? fallback : fb_rvalue);
          break;
--- 7373,7394 ----
                                        TREE_TYPE (*expr_p));
          break;
  
+       case VIEW_CONVERT_EXPR:
+         if (is_gimple_reg_type (TREE_TYPE (*expr_p))
+             && is_gimple_reg_type (TREE_TYPE (TREE_OPERAND (*expr_p, 0))))
+           {
+             ret = gimplify_expr (&TREE_OPERAND (*expr_p, 0), pre_p,
+                                  post_p, is_gimple_val, fb_rvalue);
+             recalculate_side_effects (*expr_p);
+             break;
+           }
+         /* Fallthru.  */
+ 
        case ARRAY_REF:
        case ARRAY_RANGE_REF:
        case REALPART_EXPR:
        case IMAGPART_EXPR:
        case COMPONENT_REF:
          ret = gimplify_compound_lval (expr_p, pre_p, post_p,
                                        fallback ? fallback : fb_rvalue);
          break;
Index: gcc/testsuite/gcc.dg/pr59471.c
===================================================================
*** gcc/testsuite/gcc.dg/pr59471.c      (revision 0)
--- gcc/testsuite/gcc.dg/pr59471.c      (working copy)
***************
*** 0 ****
--- 1,16 ----
+ /* { dg-do compile } */
+ 
+ typedef unsigned char uint8x4_t
+ __attribute__ ((__vector_size__ (4)));
+ 
+ typedef unsigned short uint16x8_t
+ __attribute__ ((__vector_size__ (16)));
+ 
+ typedef unsigned int uint32x4_t
+ __attribute__ ((__vector_size__ (16)));
+ 
+ uint8x4_t
+ foo (uint16x8_t x)
+ {
+   return (uint8x4_t) ((uint32x4_t) x)[0];
+ }