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Re: Vector types and type conversions
On Wed, Apr 19, 2006 at 05:30:54PM +0200, Paolo Bonzini wrote:
>
> The C spec for Altivec (not the ISA) is a horrible spec that set a
> horrible de facto standard. To some extent, gcc already departed from
> Altivec, for example by disallowing the (vector int) (1, 2, 3, 4) syntax
> -- notice the parentheses instead of the braces -- because it was
> extremely hackish to implement in a Bison parser.
The Motorola AltiVec PIM (sorry, I'm looking at a hard copy and don't
have the link handy) says:
2.4.2 Assignment
If either the left hand side or right hand side of an expression has
a vector type, then both sides of the expression must be of the same
vector type. Thus, the expression a = b is valid and represents
assignment if a and b are of the same vector type (or if neither is
a vector type). Otherwise, the expression is invalid and must be
signaled as an error by the compiler.
We can't blame this admittedly horrible spec for this one.
Janis