On 07/05/11 21:08, Richard Henderson wrote: > On 07/01/2011 10:29 AM, Bernd Schmidt wrote: >> * cse.c (find_comparison_args): Use val_mode_signbit_set_p. >> * simplify-rtx.c (mode_signbit_p): Use GET_MODE_PRECISION. >> (val_mode_signbit_p, val_mode_signbit_set_p): New functions. >> (simplify_const_unary_operation, simplify_binary_operation_1, >> simplify_const_binary_operation, >> simplify_const_relational_operation): Use them. Use >> GET_MODE_MASK for masking and sign-extensions. >> * combine.c (set_nonzero_bits_and_sign_copies, simplify_set, >> combine_simplify_rtx, force_to_mode, reg_nonzero_bits_for_combine, >> simplify_shift_const_1, simplify_comparison): Likewise. >> * expr.c (convert_modes): Likewise. >> * rtlanal.c (nonzero_bits1, canonicalize_condition): Likewise. >> * expmed.c (emit_cstore, emit_store_flag_1, emit_store_flag): >> Likewise. >> * rtl.h (val_mode_signbit_p, val_mode_signbit_set_p): Declare. > > Ok, but, > >> /* We must sign or zero-extend in this case. Start by >> zero-extending, then sign extend if we need to. */ >> - val &= ((HOST_WIDE_INT) 1 << width) - 1; >> + val &= GET_MODE_MASK (oldmode); >> if (! unsignedp >> - && (val & ((HOST_WIDE_INT) 1 << (width - 1)))) >> - val |= (HOST_WIDE_INT) (-1) << width; >> + && val_signbit_known_set_p (oldmode, val)) >> + val |= ~GET_MODE_MASK (oldmode); >> >> return gen_int_mode (val, mode); > > Shouldn't that sign-extension already be done by gen_int_mode?
I think that's a different case than the simplify_rtx one in patch #3. Here, we're extending from oldmode, while gen_int_mode takes care of the extension for mode. Thanks for the reviews! Bernd
