[Mesa-dev] Mesa (master): glsl: fix assorted MSVC warnings

[Ian Romanick]

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On 11/15/2010 05:48 PM, Brian Paul wrote:

>     case ir_unop_b2f:
>        assert(op[0]->type->base_type == GLSL_TYPE_BOOL);
>        for (unsigned c = 0; c < op[0]->type->components(); c++) {
> -	 data.f[c] = op[0]->value.b[c] ? 1.0 : 0.0;
> +	 data.f[c] = op[0]->value.b[c] ? 1.0F : 0.0F;

Please don't do this.  This particular MSVC warning should just be
disabled.  If this warning were generated for non-literals and for
literals that actually did lose precision being stored to a float, it
might have a chance at having some value.  Instead, it's just noise.

Individual warnings can be disabled with a pragma, and this one should
probably be disabled in mesa/compiler.h:

#pragma warning(disable: 4244)

There may be a way to do it from the command line, but I don't know what
it is.

The F suffixes on constants are also worthless, and they make the code
ugly.  Expecting that they will be added everywhere when no other
compiler generates this warning is a losing battle.

>        }
>        break;
>     case ir_unop_f2b:
>        assert(op[0]->type->base_type == GLSL_TYPE_FLOAT);
>        for (unsigned c = 0; c < op[0]->type->components(); c++) {
> -	 data.b[c] = bool(op[0]->value.f[c]);
> +	 data.b[c] = op[0]->value.f[c] != 0.0F ? true : false;

This warning should also be disabled for the same reason as the above.
This one isn't even a correctness warning, is a performance warning.
The code that is replacing the case may have even worse performance than
the cast!  The other changes can stay, but this one needs to be reverted.

>        }
>        break;
>     case ir_unop_b2i:
> @@ -163,7 +163,7 @@ ir_expression::constant_expression_value()
>     case ir_unop_i2b:
>        assert(op[0]->type->is_integer());
>        for (unsigned c = 0; c < op[0]->type->components(); c++) {
> -	 data.b[c] = bool(op[0]->value.u[c]);
> +	 data.b[c] = op[0]->value.u[c] ? true : false;

What warning is this?  I was unable to reproduce a warning on Visual
Studio 2008 Express Edition.  I suspect this should be reverted too.
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