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[PATCH, PR 42898] Do not create SRA piecemeal copies when volatile operands are involved


the patch below is the final missing bit required to fix PR 42898 on
trunk.  It simply treats loads/stores to volatile aggregates as those
with potential type compatibility issues and so does not create any
extra loads and stores for sub-accesses.  It also ignores statements
with volatile ops when marking aggregates for total scalarization in
order not to create unnecessary bloat.

Bootstrapped and regression tested on x86_64-linux.  OK for trunk?



2010-02-05  Martin Jambor  <>

	PR middle-end/42898
	* tree-sra.c (build_accesses_from_assign): Do not mark in
	should_scalarize_away_bitmap if stmt has volatile ops.
	(sra_modify_assign): Do not process assigns piecemeal if if stmt
	has volatile ops.

Index: mine/gcc/tree-sra.c
--- mine.orig/gcc/tree-sra.c
+++ mine/gcc/tree-sra.c
@@ -1023,7 +1023,8 @@ build_accesses_from_assign (gimple *stmt
   racc = build_access_from_expr_1 (rhs_ptr, stmt, false);
   lacc = build_access_from_expr_1 (lhs_ptr, stmt, true);
-  if (should_scalarize_away_bitmap && racc && !is_gimple_reg_type (racc->type))
+  if (should_scalarize_away_bitmap && !gimple_has_volatile_ops (stmt)
+      && racc && !is_gimple_reg_type (racc->type))
     bitmap_set_bit (should_scalarize_away_bitmap, DECL_UID (racc->base));
   if (lacc && racc
@@ -2648,7 +2649,9 @@ sra_modify_assign (gimple *stmt, gimple_
      there to do the copying and then load the scalar replacements of the LHS.
      This is what the first branch does.  */
-  if (contains_view_convert_expr_p (rhs) || contains_view_convert_expr_p (lhs)
+  if (gimple_has_volatile_ops (*stmt)
+      || contains_view_convert_expr_p (rhs)
+      || contains_view_convert_expr_p (lhs)
       || (access_has_children_p (racc)
 	  && !ref_expr_for_all_replacements_p (racc, lhs, racc->offset))
       || (access_has_children_p (lacc)

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