[PATCH] Fix PR36154, ICE in PTA

[Richard Guenther]

This fixes PR36154 where we take an address of a structure element
we don't assign a field for.  Fixed thusly.

Bootstrapped and tested on x86_64-unknown-linux-gnu, I'll apply this
to trunk and the 4.3 branch tomorrow.

Richard.

2008-05-07  Richard Guenther  <rguenther@suse.de>

	PR middle-end/36154
	* tree-ssa-structalias.c (push_fields_onto_fieldstack): Make
	sure to create a representative for trailing arrays for PTA.

	* gcc.c-torture/compile/pr36154.c: New testcase.

Index: tree-ssa-structalias.c
===================================================================
*** tree-ssa-structalias.c	(revision 135047)
--- tree-ssa-structalias.c	(working copy)
*************** push_fields_onto_fieldstack (tree type, 
*** 4180,4190 ****
  		        (DECL_NONADDRESSABLE_P (field)
  		         ? addressable_type
  		         : TREE_TYPE (field))))
! 		     && DECL_SIZE (field)
! 		     && !integer_zerop (DECL_SIZE (field)))
! 	      /* Empty structures may have actual size, like in C++. So
  	         see if we didn't push any subfields and the size is
! 	         nonzero, push the field onto the stack */
  	      push = true;
  
  	    if (push)
--- 4180,4194 ----
  		        (DECL_NONADDRESSABLE_P (field)
  		         ? addressable_type
  		         : TREE_TYPE (field))))
! 		     && ((DECL_SIZE (field)
! 			  && !integer_zerop (DECL_SIZE (field)))
! 			 || (!DECL_SIZE (field)
! 			     && TREE_CODE (TREE_TYPE (field)) == ARRAY_TYPE)))
! 	      /* Empty structures may have actual size, like in C++.  So
  	         see if we didn't push any subfields and the size is
! 	         nonzero, push the field onto the stack.  Trailing flexible
! 		 array members also need a representative to be able to
! 		 treat taking their address in PTA.  */
  	      push = true;
  
  	    if (push)
Index: testsuite/gcc.c-torture/compile/pr36154.c
===================================================================
*** testsuite/gcc.c-torture/compile/pr36154.c	(revision 0)
--- testsuite/gcc.c-torture/compile/pr36154.c	(revision 0)
***************
*** 0 ****
--- 1,11 ----
+ struct eth_test_pkt {
+   unsigned short len;
+   unsigned short ctr;
+   unsigned char packet[];
+ } __attribute__ ((packed));
+ struct eth_test_pkt pkt_unaligned = { .packet = { 0xFC } };
+ int cmd_unaligned(const void *p)
+ {
+   return memcmp(p, pkt_unaligned.packet, 1);
+ }
+