diff mbox series

Fix PR tree-optimization/108199

Message ID 2889898.e9J7NaK4W3@fomalhaut
State Accepted
Headers
Series Fix PR tree-optimization/108199 |

Checks

Context Check Description
snail/gcc-patch-check success Github commit url

Commit Message

Eric Botcazou Jan. 11, 2023, 9:59 a.m. UTC 
  Hi,

this fixes the problematic interaction between bitfields, unions, SSO and SRA.

Tested on x86-64/Linux and SPARC/Solaris, OK for all active branches?


2023-01-11  Eric Botcazou  <ebotcazou@adacore.com>
            Andreas Krebbel  <krebbel@linux.ibm.com>

	PR tree-optimization/108199
	* tree-sra.cc (sra_modify_expr): Deal with reverse storage order
	for bit-field references.


2023-01-11  Eric Botcazou  <ebotcazou@adacore.com>

	* gcc.dg/sso-17.c: New test.

Comments

Richard Biener Jan. 11, 2023, 12:03 p.m. UTC | #1 
On Wed, Jan 11, 2023 at 11:00 AM Eric Botcazou via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> Hi,
>
> this fixes the problematic interaction between bitfields, unions, SSO and SRA.
>
> Tested on x86-64/Linux and SPARC/Solaris, OK for all active branches?

OK.

Thanks,
Richard.

>
> 2023-01-11  Eric Botcazou  <ebotcazou@adacore.com>
>             Andreas Krebbel  <krebbel@linux.ibm.com>
>
>         PR tree-optimization/108199
>         * tree-sra.cc (sra_modify_expr): Deal with reverse storage order
>         for bit-field references.
>
>
> 2023-01-11  Eric Botcazou  <ebotcazou@adacore.com>
>
>         * gcc.dg/sso-17.c: New test.
>
> --
> Eric Botcazou
diff mbox series

Patch

diff --git a/gcc/tree-sra.cc b/gcc/tree-sra.cc
index f0182a45485..ad0c738645d 100644
--- a/gcc/tree-sra.cc
+++ b/gcc/tree-sra.cc
@@ -3858,7 +3858,23 @@  sra_modify_expr (tree *expr, gimple_stmt_iterator *gsi, bool write)
 	    }
 	}
       else
-	*expr = repl;
+	{
+	  /* If we are going to replace a scalar field in a structure with
+	     reverse storage order by a stand-alone scalar, we are going to
+	     effectively byte-swap the scalar and we also need to byte-swap
+	     the portion of it represented by the bit-field.  */
+	  if (bfr && REF_REVERSE_STORAGE_ORDER (bfr))
+	    {
+	      REF_REVERSE_STORAGE_ORDER (bfr) = 0;
+	      TREE_OPERAND (bfr, 2)
+		= size_binop (MINUS_EXPR, TYPE_SIZE (TREE_TYPE (repl)),
+			      size_binop (PLUS_EXPR, TREE_OPERAND (bfr, 1),
+						     TREE_OPERAND (bfr, 2)));
+	    }
+
+	  *expr = repl;
+	}
+
       sra_stats.exprs++;
     }
   else if (write && access->grp_to_be_debug_replaced)