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authorEric Botcazou <ebotcazou@adacore.com>2013-12-10 11:07:28 +0000
committerEric Botcazou <ebotcazou@gcc.gnu.org>2013-12-10 11:07:28 +0000
commitae3df2dc0a108b120304fe7725f58efc316fdd9a (patch)
tree7662eb21d49d1698fcaf48e012c2443104249515 /gcc
parented9e19a494a43647159b156737c55bde8ebf3c59 (diff)
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expr.c (expand_expr_real_1): Always return 0 for the extraction of a bit-field of null size.
* expr.c (expand_expr_real_1) <normal_inner_ref>: Always return 0 for the extraction of a bit-field of null size. From-SVN: r205855
Diffstat (limited to 'gcc')
-rw-r--r--gcc/ChangeLog5
-rw-r--r--gcc/expr.c9
2 files changed, 14 insertions, 0 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 110c0a0..73f2974 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2013-12-10 Eric Botcazou <ebotcazou@adacore.com>
+
+ * expr.c (expand_expr_real_1) <normal_inner_ref>: Always return 0 for
+ the extraction of a bit-field of null size.
+
2013-12-10 Marek Polacek <polacek@redhat.com>
PR sanitizer/59437
diff --git a/gcc/expr.c b/gcc/expr.c
index f173d03..19df9dc 100644
--- a/gcc/expr.c
+++ b/gcc/expr.c
@@ -10157,6 +10157,8 @@ expand_expr_real_1 (tree exp, rtx target, enum machine_mode tmode,
if (target == 0)
target = assign_temp (type, 1, 1);
+ /* ??? Unlike the similar test a few lines below, this one is
+ very likely obsolete. */
if (bitsize == 0)
return target;
@@ -10177,6 +10179,13 @@ expand_expr_real_1 (tree exp, rtx target, enum machine_mode tmode,
return target;
}
+ /* If we have nothing to extract, the result will be 0 for targets
+ with SHIFT_COUNT_TRUNCATED == 0 and garbage otherwise. Always
+ return 0 for the sake of consistency, as reading a zero-sized
+ bitfield is valid in Ada and the value is fully specified. */
+ if (bitsize == 0)
+ return const0_rtx;
+
op0 = validize_mem (op0);
if (MEM_P (op0) && REG_P (XEXP (op0, 0)))