Re: [PATCH] [MSP430] Fix gcc.dg/pr85180.c and gcc.dg/pr87985.c timeouts for msp430-elf -mlarge

[Segher Boessenkool <segher at kernel dot crashing dot org>]

Hi!

On Fri, Dec 14, 2018 at 03:22:13PM +0000, Jozef Lawrynowicz wrote:
> 2018-12-14  Jozef Lawrynowicz  <jozef.l@mittosystems.com>
> 
> 	gcc/ChangeLog:
> 	* combine.c (update_rsp_from_reg_equal): Only look for the nonzero bits
> 	of src in nonzero_bits_mode if the mode of src is MODE_INT and
> 	HWI_COMPUTABLE.
> 	(reg_nonzero_bits_for_combine): Add clarification to comment.

Is there some PR this fixes?

> 
> diff --git a/gcc/combine.c b/gcc/combine.c
> index 7e61139..c93aaed 100644
> --- a/gcc/combine.c
> +++ b/gcc/combine.c
> @@ -1698,9 +1698,13 @@ update_rsp_from_reg_equal (reg_stat_type *rsp, rtx_insn *insn, const_rtx set,
>    /* Don't call nonzero_bits if it cannot change anything.  */
>    if (rsp->nonzero_bits != HOST_WIDE_INT_M1U)
>      {
> -      bits = nonzero_bits (src, nonzero_bits_mode);
> +      machine_mode mode = GET_MODE (x);
> +      if (GET_MODE_CLASS (mode) == MODE_INT
> +	  && HWI_COMPUTABLE_MODE_P (mode))
> +	mode = nonzero_bits_mode;
> +      bits = nonzero_bits (src, mode);
>        if (reg_equal && bits)
> -	bits &= nonzero_bits (reg_equal, nonzero_bits_mode);
> +	bits &= nonzero_bits (reg_equal, mode);
>        rsp->nonzero_bits |= bits;
>      }
>  
> @@ -10224,6 +10228,7 @@ simplify_and_const_int (rtx x, scalar_int_mode mode, rtx varop,
>  
>  /* Given a REG X of mode XMODE, compute which bits in X can be nonzero.
>     We don't care about bits outside of those defined in MODE.
> +   We DO care about all the bits in MODE, even if XMODE is smaller than MODE.
>  
>     For most X this is simply GET_MODE_MASK (GET_MODE (MODE)), but if X is
>     a shift, AND, or zero_extract, we can do better.  */

I think this is okay for trunk, and for backports after waiting a week
or so for fallout.  Thanks!


Segher