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Diffstat (limited to 'gcc-4.6/gcc/expr.c')
| -rw-r--r-- | gcc-4.6/gcc/expr.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/gcc-4.6/gcc/expr.c b/gcc-4.6/gcc/expr.c index 31f04e301..5cb5df7a2 100644 --- a/gcc-4.6/gcc/expr.c +++ b/gcc-4.6/gcc/expr.c @@ -9192,8 +9192,16 @@ expand_expr_real_1 (tree exp, rtx target, enum machine_mode tmode, && modifier != EXPAND_CONST_ADDRESS && modifier != EXPAND_INITIALIZER) /* If the field is volatile, we always want an aligned - access. */ - || (volatilep && flag_strict_volatile_bitfields > 0) + access. Do this in following two situations: + 1. the access is not already naturally + aligned, otherwise "normal" (non-bitfield) volatile fields + become non-addressable. + 2. the bitsize is narrower than the access size. Need + to extract bitfields from the access. */ + || (volatilep && flag_strict_volatile_bitfields > 0 + && (bitpos % GET_MODE_ALIGNMENT (mode) != 0 + || (mode1 != BLKmode + && bitsize < GET_MODE_SIZE (mode1) * BITS_PER_UNIT))) /* If the field isn't aligned enough to fetch as a memref, fetch it as a bit field. */ || (mode1 != BLKmode |