[PATCH v3 4/8] change the masking when loading bitfields

[Luc Van Oostenryck <luc.vanoostenryck@gmail.com>]

To make some simplification easier, change the way the masking
is done when loading bitfields.

Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
---
 linearize.c                | 15 +++++++++------
 validation/bitfield-size.c |  6 ++++--
 2 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/linearize.c b/linearize.c
index ba76397ea..f833fd8d9 100644
--- a/linearize.c
+++ b/linearize.c
@@ -1000,14 +1000,17 @@ static pseudo_t linearize_load_gen(struct entrypoint *ep, struct access_data *ad
 {
 	struct symbol *ctype = ad->result_type;
 	pseudo_t new = add_load(ep, ad);
+	unsigned int off = ctype->bit_offset;
+	unsigned int siz = ctype->bit_size;
 
-	if (ctype->bit_offset) {
-		pseudo_t shift = value_pseudo(ctype->bit_offset);
-		pseudo_t newval = add_binary_op(ep, ad->source_type, OP_LSR, new, shift);
-		new = newval;
+	if (siz != type_size(ad->source_type)) {
+		pseudo_t mask = value_pseudo(((1ULL << siz) - 1) << off);
+		new = add_binary_op(ep, ad->source_type, OP_AND, new, mask);
+	}
+	if (off) {
+		pseudo_t shift = value_pseudo(off);
+		new = add_binary_op(ep, ad->source_type, OP_LSR, new, shift);
 	}
-	if (ctype->bit_size != type_size(ad->source_type))
-		new = cast_pseudo(ep, new, ad->source_type, ad->result_type);
 	return new;
 }
 
diff --git a/validation/bitfield-size.c b/validation/bitfield-size.c
index ce78ecf21..c8c94bb15 100644
--- a/validation/bitfield-size.c
+++ b/validation/bitfield-size.c
@@ -35,7 +35,9 @@ unsigned int get_pbfi_b(struct bfi *bf) { return bf->b; }
  * check-command: test-linearize -Wno-decl $file
  * check-output-ignore
  *
- * check-output-pattern-24-times: cast\\.
- * check-output-pattern-12-times: cast\\.4
+ * check-output-excludes: cast\\.4
+ * check-output-pattern-6-times: cast\\.
  * check-output-pattern-6-times: lsr\\..*\\$6
+ * check-output-pattern-6-times: and\\..*\\$15
+ * check-output-pattern-6-times: and\\..*\\$960
  */
-- 
2.13.2