----- Original Message -----
> This patch expects to be applied after the "Constants through
> builtins
> evaluation rewrite" for two reasons:
> - a line of that patch appears in the context
> - the ir_function side changes that the old method would need are not
> present (and they would conflict)
>
> At that point a "test_out = floatBitsToUint(-1.0);" fired through the
> glsl compiler gives a correct "(assign (x) (var_ref test_out)
> (constant uint (3212836864)))"
>
> Signed-off-by: Olivier Galibert <galib...@pobox.com>
> ---
> src/glsl/ir_constant_expression.cpp | 47
> +++++++++++++++++++++++++++++++++++
> 1 file changed, 47 insertions(+)
>
> diff --git a/src/glsl/ir_constant_expression.cpp
> b/src/glsl/ir_constant_expression.cpp
> index 61c0ae6..5923bb4 100644
> --- a/src/glsl/ir_constant_expression.cpp
> +++ b/src/glsl/ir_constant_expression.cpp
> @@ -71,6 +71,29 @@ dot(ir_constant *op0, ir_constant *op1)
> return result;
> }
>
> +/* This method is the only one supported by gcc. Unions in
> particular
> + * are iffy, and read-through-converted-pointer is killed by strict
> + * aliasing. OTOH, the compiler sees through the memcpy, so the
> + * resulting asm is reasonable.
> + */
> +static float
> +bitcast_u2f(unsigned int u)
> +{
> + assert(sizeof(float) == sizeof(unsigned int));
> + float f;
> + memcpy(&f, &u, sizeof(f));
> + return f;
> +}
> +
> +static unsigned int
> +bitcast_f2u(float f)
> +{
> + assert(sizeof(float) == sizeof(unsigned int));
> + unsigned int u;
> + memcpy(&u, &f, sizeof(f));
> + return u;
> +}
> +
> ir_constant *
> ir_rvalue::constant_expression_value(struct hash_table
> *variable_context)
> {
> @@ -207,6 +230,30 @@ ir_expression::constant_expression_value(struct
> hash_table *variable_context)
> data.u[c] = op[0]->value.i[c];
> }
> break;
> + case ir_unop_bitcast_i2f:
> + assert(op[0]->type->base_type == GLSL_TYPE_INT);
> + for (unsigned c = 0; c < op[0]->type->components(); c++) {
> + data.f[c] = bitcast_u2f(op[0]->value.i[c]);
Shouldn't it be bitcast_i2f ?
> + }
> + break;
> + case ir_unop_bitcast_f2i:
> + assert(op[0]->type->base_type == GLSL_TYPE_FLOAT);
> + for (unsigned c = 0; c < op[0]->type->components(); c++) {
> + data.i[c] = bitcast_f2u(op[0]->value.f[c]);
And bitcast_f2i here ?
> + }
> + break;
> + case ir_unop_bitcast_u2f:
> + assert(op[0]->type->base_type == GLSL_TYPE_UINT);
> + for (unsigned c = 0; c < op[0]->type->components(); c++) {
> + data.f[c] = bitcast_u2f(op[0]->value.u[c]);
> + }
> + break;
> + case ir_unop_bitcast_f2u:
> + assert(op[0]->type->base_type == GLSL_TYPE_FLOAT);
> + for (unsigned c = 0; c < op[0]->type->components(); c++) {
> + data.u[c] = bitcast_f2u(op[0]->value.f[c]);
> + }
> + break;
> case ir_unop_any:
> assert(op[0]->type->is_boolean());
> data.b[0] = false;
> --
> 1.7.10.rc3.1.gb306
>
> _______________________________________________
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> mesa-dev@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/mesa-dev
>
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