From eea05d39c799880df753e9b74d2d96e86215c46e Mon Sep 17 00:00:00 2001 From: Eric Botcazou Date: Sun, 20 Apr 2008 17:53:58 +0000 Subject: tree-sra.c (sra_walk_expr): Disable scalarization if on the LHS and not a full access. * tree-sra.c (sra_walk_expr) : Disable scalarization if on the LHS and not a full access. From-SVN: r134487 --- gcc/tree-sra.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) (limited to 'gcc/tree-sra.c') diff --git a/gcc/tree-sra.c b/gcc/tree-sra.c index 752f87d..78a100f 100644 --- a/gcc/tree-sra.c +++ b/gcc/tree-sra.c @@ -855,18 +855,28 @@ sra_walk_expr (tree *expr_p, block_stmt_iterator *bsi, bool is_output, if (elt) elt->is_vector_lhs = true; } + /* A bit field reference (access to *multiple* fields simultaneously) - is not currently scalarized. Consider this an access to the - complete outer element, to which walk_tree will bring us next. */ - + is not currently scalarized. Consider this an access to the full + outer element, to which walk_tree will bring us next. */ goto use_all; - case VIEW_CONVERT_EXPR: case NOP_EXPR: - /* Similarly, a view/nop explicitly wants to look at an object in a + /* Similarly, a nop explicitly wants to look at an object in a type other than the one we've scalarized. */ goto use_all; + case VIEW_CONVERT_EXPR: + /* Likewise for a view conversion, but with an additional twist: + it can be on the LHS and, in this case, an access to the full + outer element would mean a killing def. So we need to punt + if we haven't already a full access to the current element, + because we cannot pretend to have a killing def if we only + have a partial access at some level. */ + if (is_output && !use_all_p && inner != expr) + disable_scalarization = true; + goto use_all; + case WITH_SIZE_EXPR: /* This is a transparent wrapper. The entire inner expression really is being used. */ -- cgit v1.1