Patch gcc-4.0 should not apply mathematical associative rules for addition or multiplication

[Geoff Keating]

On 05/10/2004, at 1:04 PM, Fariborz Jahanian wrote:

>>> +            && (code == MULT_EXPR || code == PLUS_EXPR)
>>> +            && FLOAT_TYPE_P (TREE_TYPE (exp)));
>>
>> This function appears to disallow folding
>>
>> (x * 2.0) * 2.0
>>
>> into
>>
>> x * 4.0
>>
>> which seems to me to be valid.
>
> Wording of ANSIC disallows such foldings even if it is safe sometimes.

Could you explain why you think the standard says this?  The quote you 
gave said "In the following fragment, rearrangements suggested by 
mathematical rules for real numbers are often not valid" but it did not 
say that they were *always* not valid.
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