diff options
Diffstat (limited to 'gcc/fold-const.c')
| -rw-r--r-- | gcc/fold-const.c | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/gcc/fold-const.c b/gcc/fold-const.c index 6c4f7f8..33b8dc8 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -7530,6 +7530,8 @@ native_interpret_expr (tree type, const unsigned char *ptr, int len) case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE: + case POINTER_TYPE: + case REFERENCE_TYPE: return native_interpret_int (type, ptr, len); case REAL_TYPE: @@ -7546,6 +7548,27 @@ native_interpret_expr (tree type, const unsigned char *ptr, int len) } } +/* Returns true if we can interpret the contents of a native encoding + as TYPE. */ + +static bool +can_native_interpret_type_p (tree type) +{ + switch (TREE_CODE (type)) + { + case INTEGER_TYPE: + case ENUMERAL_TYPE: + case BOOLEAN_TYPE: + case POINTER_TYPE: + case REFERENCE_TYPE: + case REAL_TYPE: + case COMPLEX_TYPE: + case VECTOR_TYPE: + return true; + default: + return false; + } +} /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type TYPE at compile-time. If we're unable to perform the conversion @@ -13978,6 +14001,40 @@ fold_ternary_loc (location_t loc, enum tree_code code, tree type, && integer_zerop (op2)) return fold_convert_loc (loc, type, arg0); + /* On constants we can use native encode/interpret to constant + fold (nearly) all BIT_FIELD_REFs. */ + if (CONSTANT_CLASS_P (arg0) + && can_native_interpret_type_p (type) + && host_integerp (TYPE_SIZE_UNIT (TREE_TYPE (arg0)), 1) + /* This limitation should not be necessary, we just need to + round this up to mode size. */ + && tree_low_cst (op1, 1) % BITS_PER_UNIT == 0 + /* Need bit-shifting of the buffer to relax the following. */ + && tree_low_cst (op2, 1) % BITS_PER_UNIT == 0) + { + unsigned HOST_WIDE_INT bitpos = tree_low_cst (op1, 2); + unsigned HOST_WIDE_INT bitsize = tree_low_cst (op1, 1); + unsigned HOST_WIDE_INT clen; + clen = tree_low_cst (TYPE_SIZE_UNIT (TREE_TYPE (arg0)), 1); + /* ??? We cannot tell native_encode_expr to start at + some random byte only. So limit us to a reasonable amount + of work. */ + if (clen <= 4096) + { + unsigned char *b = XALLOCAVEC (unsigned char, clen); + unsigned HOST_WIDE_INT len = native_encode_expr (arg0, b, clen); + if (len > 0 + && len * BITS_PER_UNIT >= bitpos + bitsize) + { + tree v = native_interpret_expr (type, + b + bitpos / BITS_PER_UNIT, + bitsize / BITS_PER_UNIT); + if (v) + return v; + } + } + } + return NULL_TREE; case FMA_EXPR: |