[PATCH] Amend fixes for PR26134 and PR48037

[Richard Guenther]

This makes sure we also rewrite complex variables into SSA form if
we extract components via pointer-to-elements.

Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.

Richard.

2011-03-16  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/26134
	* tree-ssa.c (maybe_rewrite_mem_ref_base): Handle rewriting
	complex part accesses to REALPART_EXPR and IMAGPART_EXPR.
	(non_rewritable_mem_ref_base): Handle complex type component
	accesses, constrain offsets for vector and complex extracts
	more properly.

	* gcc.dg/tree-ssa/complex-6.c: New testcase.

Index: gcc/tree-ssa.c
===================================================================
*** gcc/tree-ssa.c	(revision 171042)
--- gcc/tree-ssa.c	(working copy)
*************** maybe_rewrite_mem_ref_base (tree *tp)
*** 1855,1860 ****
--- 1855,1868 ----
  					 bitsize_int (BITS_PER_UNIT),
  					 TREE_OPERAND (*tp, 1), 0));
  	}
+       else if (TREE_CODE (TREE_TYPE (sym)) == COMPLEX_TYPE
+ 	       && useless_type_conversion_p (TREE_TYPE (*tp),
+ 					     TREE_TYPE (TREE_TYPE (sym))))
+ 	{
+ 	  *tp = build1 (integer_zerop (TREE_OPERAND (*tp, 1))
+ 			? REALPART_EXPR : IMAGPART_EXPR,
+ 			TREE_TYPE (*tp), sym);
+ 	}
        else if (integer_zerop (TREE_OPERAND (*tp, 1)))
  	{
  	  if (!useless_type_conversion_p (TREE_TYPE (*tp),
*************** non_rewritable_mem_ref_base (tree ref)
*** 1888,1897 ****
        && TREE_CODE (TREE_OPERAND (base, 0)) == ADDR_EXPR)
      {
        tree decl = TREE_OPERAND (TREE_OPERAND (base, 0), 0);
!       if (TREE_CODE (TREE_TYPE (decl)) == VECTOR_TYPE
  	  && useless_type_conversion_p (TREE_TYPE (base),
  					TREE_TYPE (TREE_TYPE (decl)))
  	  && double_int_fits_in_uhwi_p (mem_ref_offset (base))
  	  && multiple_of_p (sizetype, TREE_OPERAND (base, 1),
  			    TYPE_SIZE_UNIT (TREE_TYPE (base))))
  	return NULL_TREE;
--- 1896,1909 ----
        && TREE_CODE (TREE_OPERAND (base, 0)) == ADDR_EXPR)
      {
        tree decl = TREE_OPERAND (TREE_OPERAND (base, 0), 0);
!       if ((TREE_CODE (TREE_TYPE (decl)) == VECTOR_TYPE
! 	   || TREE_CODE (TREE_TYPE (decl)) == COMPLEX_TYPE)
  	  && useless_type_conversion_p (TREE_TYPE (base),
  					TREE_TYPE (TREE_TYPE (decl)))
  	  && double_int_fits_in_uhwi_p (mem_ref_offset (base))
+ 	  && double_int_ucmp
+ 	       (tree_to_double_int (TYPE_SIZE_UNIT (TREE_TYPE (decl))),
+ 		mem_ref_offset (base)) == 1
  	  && multiple_of_p (sizetype, TREE_OPERAND (base, 1),
  			    TYPE_SIZE_UNIT (TREE_TYPE (base))))
  	return NULL_TREE;
Index: gcc/testsuite/gcc.dg/tree-ssa/complex-6.c
===================================================================
*** gcc/testsuite/gcc.dg/tree-ssa/complex-6.c	(revision 0)
--- gcc/testsuite/gcc.dg/tree-ssa/complex-6.c	(revision 0)
***************
*** 0 ****
--- 1,25 ----
+ /* { dg-do compile } */
+ /* { dg-options "-O -fdump-tree-optimized" } */
+ 
+ float
+ quantum_real(float _Complex a)
+ {
+   float *p = (float *) &a;
+   return p[0];
+ }
+ float
+ quantum_imag(float _Complex a)
+ {
+   float *p = (float *) &a;
+   return p[1];
+ }
+ float
+ quantum_foo(float _Complex a)
+ {
+   float *p = (float *) &a;
+   return p[2];
+ }
+ 
+ /* { dg-final { scan-tree-dump-times "REALPART_EXPR" 1 "optimized" } } */
+ /* { dg-final { scan-tree-dump-times "IMAGPART_EXPR" 1 "optimized" } } */
+ /* { dg-final { cleanup-tree-dump "optimized" } } */