Patchwork [wide-int] resolve bootstrap issue

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Submitter Mike Stump
Date Jan. 15, 2014, 9:51 p.m.
Message ID <8186E313-3627-46CA-9301-44AAC5F14D99@comcast.net>
Download mbox | patch
Permalink /patch/311308/
State New
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Comments

Mike Stump - Jan. 15, 2014, 9:51 p.m.
On Jan 14, 2014, at 7:25 AM, Richard Sandiford <rsandifo@linux.vnet.ibm.com> wrote:
> Mike Stump <mikestump@comcast.net> writes:
>> diff --git a/gcc/expmed.c b/gcc/expmed.c
>> index ce063eb..720d8c1 100644
>> --- a/gcc/expmed.c
>> +++ b/gcc/expmed.c
>> @@ -4963,6 +4963,7 @@ make_tree (tree type, rtx x)
>>       return t;
>> 
>>     case CONST_DOUBLE:
>> +      gcc_assert (HOST_BITS_PER_WIDE_INT * 2 <= MAX_BITSIZE_MODE_ANY_INT);
>>       if (TARGET_SUPPORTS_WIDE_INT == 0 && GET_MODE (x) == VOIDmode)
>> 	t = wide_int_to_tree (type,
>> 			      wide_int::from_array (&CONST_DOUBLE_LOW (x), 2,
> 
> I think this would be better as a STATIC_ASSERT.

The cost should be the same in generated code.  The C folks can read and understand the gcc_assert easier, and the static property of the check we don't make any use of.  I could change it, but there are 0 of these in *.c presently, and I think we want to tread lightly on those folks that know and like C, and don't want gcc to be `different' for no good reason.  That said, if people think it would be good to use it, I'd be happy to change it.

>> @@ -1440,10 +1442,10 @@ real_to_integer (const REAL_VALUE_TYPE *r, bool *fail, int precision)
>> 	}
>> #endif
>>       w = SIGSZ * HOST_BITS_PER_LONG + words * HOST_BITS_PER_WIDE_INT;
>> -      result = wide_int::from_array
>> +      tmp = real_int::from_array
>> 	(val, (w + HOST_BITS_PER_WIDE_INT - 1) / HOST_BITS_PER_WIDE_INT, w);
>> -      result = wi::lrshift (result, (words * HOST_BITS_PER_WIDE_INT) - exp);
>> -      result = wide_int::from (result, precision, UNSIGNED);
>> +      tmp = wi::lrshift<real_int> (tmp, (words * HOST_BITS_PER_WIDE_INT) - exp);
>> +      result = wide_int::from (tmp, precision, UNSIGNED);
> 
> Why did you need the <real_int>?  It was supposed to work without.

The code in question needs something that is max int + max significand real in size, we made the max int smaller (smaller than this quantity on x86) so, this code needs a special wide int that is bigger.  The type is free as vrp uses the same type.  As for why Kenny choose this method, I'd defer to him.

>> diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c
>> index 00b5439..7c21afa 100644
>> --- a/gcc/simplify-rtx.c
>> +++ b/gcc/simplify-rtx.c
>> @@ -5384,6 +5384,7 @@ simplify_immed_subreg (enum machine_mode outermode, rtx op,
>> 		tmp[u] = buf;
>> 		base += HOST_BITS_PER_WIDE_INT;
>> 	      }
>> +	    gcc_assert (GET_MODE_PRECISION (outer_submode) <= MAX_BITSIZE_MODE_ANY_INT);
>> 	    r = wide_int::from_array (tmp, units,
>> 				      GET_MODE_PRECISION (outer_submode));
>> 	    elems[elem] = immed_wide_int_const (r, outer_submode);
> 
> Long line.

Fixed:


Thanks for the review.

Patch

Index: simplify-rtx.c
===================================================================
--- simplify-rtx.c	(revision 206601)
+++ simplify-rtx.c	(working copy)
@@ -5384,7 +5384,8 @@  simplify_immed_subreg (enum machine_mode
 		tmp[u] = buf;
 		base += HOST_BITS_PER_WIDE_INT;
 	      }
-	    gcc_assert (GET_MODE_PRECISION (outer_submode) <= MAX_BITSIZE_MODE_ANY_INT);
+	    gcc_assert (GET_MODE_PRECISION (outer_submode)
+			<= MAX_BITSIZE_MODE_ANY_INT);
 	    r = wide_int::from_array (tmp, units,
 				      GET_MODE_PRECISION (outer_submode));
 	    elems[elem] = immed_wide_int_const (r, outer_submode);