rusticl: enable proper fp16 support

Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Reviewed-by: Adam Jackson <ajax@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34053>

docs/envvars.rst

@@ -1186,7 +1186,6 @@ Rusticl environment variables
    a comma-separated list of features to enable. Those are disabled by default
    as they might not be stable enough or break OpenCL conformance.
 
-   - ``fp16`` enables OpenCL half support
    - ``fp64`` enables OpenCL double support
    - ``intel`` enables various Intel OpenCL extensions
 

docs/features.txt

@@ -819,7 +819,7 @@ Rusticl extensions that are not part of any OpenCL version:
   cl_khr_expect_assume                                  in progress (hints are ignored)
   cl_khr_extended_async_copies                          not started
   cl_khr_extended_bit_ops                               in progress
-  cl_khr_fp16                                           in progress (llvmpipe, radeonsi, zink, Available with environment variable RUSTICL_FEATURES=fp16)
+  cl_khr_fp16                                           DONE (asahi, freedreno, llvmpipe, panfrost, radeonsi, zink)
   cl_khr_gl_depth_images                                not started
   cl_khr_gl_msaa_sharing                                not started
   cl_khr_gl_sharing                                     DONE (iris, radeonsi, zink)

docs/relnotes/new_features.txt

@@ -36,3 +36,4 @@ VK_KHR_load_store_op_none on panvk
 VK_EXT_load_store_op_none on panvk
 VK_EXT_scalar_block_layout on radv/gfx6
 VK_EXT_inline_uniform_block on panvk
+cl_khr_fp16 on asahi, freedreno, llvmpipe, panfrost, radeonsi and zink

src/gallium/frontends/rusticl/core/device.rs

@@ -888,10 +888,6 @@ impl Device {
     }
 
     pub fn fp16_supported(&self) -> bool {
-        if !Platform::features().fp16 {
-            return false;
-        }
-
         self.shader_caps().fp16
     }
 

src/gallium/frontends/rusticl/core/platform.rs

@@ -67,7 +67,6 @@ pub struct PlatformDebug {
 }
 
 pub struct PlatformFeatures {
-    pub fp16: bool,
     pub fp64: bool,
     pub intel: bool,
 }
@@ -96,7 +95,6 @@ static mut PLATFORM_DBG: PlatformDebug = PlatformDebug {
     validate_spirv: false,
 };
 static mut PLATFORM_FEATURES: PlatformFeatures = PlatformFeatures {
-    fp16: false,
     fp64: false,
     intel: false,
 };
@@ -134,7 +132,6 @@ fn load_env() {
     if let Ok(feature_flags) = env::var("RUSTICL_FEATURES") {
         for flag in feature_flags.split(',') {
             match flag {
-                "fp16" => features.fp16 = true,
                 "fp64" => features.fp64 = true,
                 "intel" => features.intel = true,
                 "" => (),

src/gallium/frontends/rusticl/mesa/compiler/clc/spirv.rs

@@ -518,7 +518,9 @@ impl CLCSpecConstantType for clc_spec_constant_type {
             Self::CLC_SPEC_CONSTANT_INT32
             | Self::CLC_SPEC_CONSTANT_UINT32
             | Self::CLC_SPEC_CONSTANT_FLOAT => 4,
-            Self::CLC_SPEC_CONSTANT_INT16 | Self::CLC_SPEC_CONSTANT_UINT16 => 2,
+            Self::CLC_SPEC_CONSTANT_INT16
+            | Self::CLC_SPEC_CONSTANT_UINT16
+            | Self::CLC_SPEC_CONSTANT_HALF => 2,
             Self::CLC_SPEC_CONSTANT_INT8
             | Self::CLC_SPEC_CONSTANT_UINT8
             | Self::CLC_SPEC_CONSTANT_BOOL => 1,