[PATCH][4.3] Fix PR36187, wrong partitioning with SFTs and unions

[Richard Guenther]

With the testcase in this PR we forget to mark unpartitionable SFTs as
such if going through the special case for unions in set_uids_in_ptset.

Fixed with the following patch, bootstrap & regtest on 
x86_64-unknown-linxu-gnu in progress.  I'll apply this to the branch
after it succeeded.

Thanks,
Richard.

2008-05-09  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/36187
	* tree-dfa.c (dump_variable): Correct dumping of
	SFT_BASE_FOR_COMPONENTS_P.
	* tree-ssa-structalias.c (set_uids_in_ptset): Set
	SFT_UNPARTITIONABLE_P correctly for the union case.

	* g++.dg/pr36187.C: New testcase.

Index: gcc/tree-dfa.c
===================================================================
*** gcc/tree-dfa.c	(revision 135071)
--- gcc/tree-dfa.c	(working copy)
*************** dump_variable (FILE *file, tree var)
*** 426,432 ****
  	  fprintf (file, ", offset: " HOST_WIDE_INT_PRINT_UNSIGNED,
  		   SFT_OFFSET (var));
  	  fprintf (file, ", base for components: %s",
! 		   SFT_BASE_FOR_COMPONENTS_P (var) ? "NO" : "YES");
  	  fprintf (file, ", partitionable: %s",
  		   SFT_UNPARTITIONABLE_P (var) ? "NO" : "YES");
  	}
--- 426,432 ----
  	  fprintf (file, ", offset: " HOST_WIDE_INT_PRINT_UNSIGNED,
  		   SFT_OFFSET (var));
  	  fprintf (file, ", base for components: %s",
! 		   SFT_BASE_FOR_COMPONENTS_P (var) ? "YES" : "NO");
  	  fprintf (file, ", partitionable: %s",
  		   SFT_UNPARTITIONABLE_P (var) ? "NO" : "YES");
  	}
Index: gcc/tree-ssa-structalias.c
===================================================================
*** gcc/tree-ssa-structalias.c	(revision 135072)
--- gcc/tree-ssa-structalias.c	(working copy)
*************** set_uids_in_ptset (tree ptr, bitmap into
*** 4757,4763 ****
  	  /* Variables containing unions may need to be converted to
  	     their SFT's, because SFT's can have unions and we cannot.  */
  	  for (i = 0; VEC_iterate (tree, sv, i, subvar); ++i)
! 	    bitmap_set_bit (into, DECL_UID (subvar));
  	}
        else if (TREE_CODE (vi->decl) == VAR_DECL
  	       || TREE_CODE (vi->decl) == PARM_DECL
--- 4757,4775 ----
  	  /* Variables containing unions may need to be converted to
  	     their SFT's, because SFT's can have unions and we cannot.  */
  	  for (i = 0; VEC_iterate (tree, sv, i, subvar); ++i)
! 	    {
! 	      /* Pointed-to SFTs are needed by the operand scanner
! 		 to adjust offsets when adding operands to memory
! 		 expressions that dereference PTR.  This means
! 		 that memory partitioning may not partition
! 		 this SFT because the operand scanner will not
! 		 be able to find the other SFTs next to this
! 		 one.  But we only need to do this if the pointed
! 		 to type is aggregate.  */
! 	      if (SFT_BASE_FOR_COMPONENTS_P (subvar))
! 		SFT_UNPARTITIONABLE_P (subvar) = true;
! 	      bitmap_set_bit (into, DECL_UID (subvar));
! 	    }
  	}
        else if (TREE_CODE (vi->decl) == VAR_DECL
  	       || TREE_CODE (vi->decl) == PARM_DECL
Index: gcc/testsuite/g++.dg/pr36187.C
===================================================================
*** gcc/testsuite/g++.dg/pr36187.C	(revision 0)
--- gcc/testsuite/g++.dg/pr36187.C	(revision 0)
***************
*** 0 ****
--- 1,45 ----
+ /* { dg-do run } */
+ /* { dg-options "-O2 --param max-aliased-vops=20" } */
+ 
+ extern "C" void abort (void);
+ enum SbxDataType { SbxINTEGER, SbxDECIMAL, SbxBYREF = 0x4000 };
+ struct SbxValues {
+     union {
+ 	float nSingle;
+ 	float* pSingle;
+     };
+     SbxDataType eType;
+ };
+ static bool ImpPutDoubleFoo( SbxValues* p)
+ {
+     bool bRet = false;
+     SbxValues aTmp;
+     int count = 0;
+ start: 
+     switch( p->eType )  {  
+ 	case SbxINTEGER:
+ 	    if (count++ > 0)
+ 	      abort ();
+ 	    aTmp.pSingle = &p->nSingle; goto direct;
+ 	case SbxBYREF | SbxDECIMAL:
+ 	    bRet = false;
+ 	    break;
+ 	direct:
+ 	    aTmp.eType = SbxDataType( p->eType | SbxBYREF );
+ 	    p = &aTmp; goto start;
+ 	case SbxBYREF | SbxINTEGER:
+ 	    break;
+ 	default:
+ 	    bRet =true;
+     }
+     return bRet;
+ }
+ 
+ int main( int argc, char** argv )
+ {
+     SbxValues aTmp;
+     aTmp.eType = SbxINTEGER;
+     if ( ImpPutDoubleFoo( &aTmp ) )
+ 	abort ();
+     return 0;
+ }