radv: fix dual source blending
Add the index to the location when assigning driver locations for
output variables.
Otherwise two fragment shader outputs declared as:
layout (location = 0, index = 0) out vec4 output1;
layout (location = 0, index = 1) out vec4 output2;
will end up aliasing one another.
Note that this patch will make the second output variable in the above
example alias a possible third output variable with location = 1 and
index = 0. But this shouldn't be a problem in practice since only one
color attachment is supported when dual-source blending is used.
Cc: "13.0" <mesa-stable@lists.freedesktop.org>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
diff --git a/src/amd/common/ac_nir_to_llvm.c b/src/amd/common/ac_nir_to_llvm.c
index d66fefb..90ee917 100644
--- a/src/amd/common/ac_nir_to_llvm.c
+++ b/src/amd/common/ac_nir_to_llvm.c
@@ -4125,7 +4125,7 @@
handle_shader_output_decl(struct nir_to_llvm_context *ctx,
struct nir_variable *variable)
{
- int idx = variable->data.location;
+ int idx = variable->data.location + variable->data.index;
unsigned attrib_count = glsl_count_attribute_slots(variable->type, false);
variable->data.driver_location = idx * 4;
@@ -4155,7 +4155,7 @@
si_build_alloca_undef(ctx, ctx->f32, "");
}
}
- ctx->output_mask |= ((1ull << attrib_count) - 1) << variable->data.location;
+ ctx->output_mask |= ((1ull << attrib_count) - 1) << idx;
}
static void
