radeonsi: add a helper for extracting bitfields from parameters (v2)

This will be used a lot (especially by tessellation).

v2: don't use the bfe intrinsic

Reviewed-by: Tom Stellard <thomas.stellard@amd.com>

diff --git a/src/gallium/drivers/radeonsi/si_shader.c b/src/gallium/drivers/radeonsi/si_shader.c
index 2703704a7fe9027db9b431ffc4d3d488541532ee..de889ed2e4f3d70f83a49083a024daebbd0e4b8b 100644 (file)
--- a/src/gallium/drivers/radeonsi/si_shader.c
+++ b/src/gallium/drivers/radeonsi/si_shader.c
@@ -191,6 +191,30 @@ static int get_param_index(unsigned semantic_name, unsigned index,
        return -1;
 }
 
+/**
+ * Get the value of a shader input parameter and extract a bitfield.
+ */
+static LLVMValueRef unpack_param(struct si_shader_context *si_shader_ctx,
+                                unsigned param, unsigned rshift,
+                                unsigned bitwidth)
+{
+       struct gallivm_state *gallivm = &si_shader_ctx->radeon_bld.gallivm;
+       LLVMValueRef value = LLVMGetParam(si_shader_ctx->radeon_bld.main_fn,
+                                         param);
+
+       if (rshift)
+               value = LLVMBuildLShr(gallivm->builder, value,
+                                     lp_build_const_int32(gallivm, rshift), "");
+
+       if (rshift + bitwidth < 32) {
+               unsigned mask = (1 << bitwidth) - 1;
+               value = LLVMBuildAnd(gallivm->builder, value,
+                                    lp_build_const_int32(gallivm, mask), "");
+       }
+
+       return value;
+}
+
 /**
  * Build an LLVM bytecode indexed load using LLVMBuildGEP + LLVMBuildLoad.
  * It's equivalent to doing a load from &base_ptr[index].
@@ -561,14 +585,8 @@ static void declare_input_fs(
 
 static LLVMValueRef get_sample_id(struct radeon_llvm_context *radeon_bld)
 {
-       struct gallivm_state *gallivm = &radeon_bld->gallivm;
-       LLVMValueRef value = LLVMGetParam(radeon_bld->main_fn,
-                                         SI_PARAM_ANCILLARY);
-       value = LLVMBuildLShr(gallivm->builder, value,
-                             lp_build_const_int32(gallivm, 8), "");
-       value = LLVMBuildAnd(gallivm->builder, value,
-                            lp_build_const_int32(gallivm, 0xf), "");
-       return value;
+       return unpack_param(si_shader_context(&radeon_bld->soa.bld_base),
+                           SI_PARAM_ANCILLARY, 8, 4);
 }
 
 /**
@@ -1013,16 +1031,9 @@ static void si_llvm_emit_streamout(struct si_shader_context *shader,
 
        LLVMTypeRef i32 = LLVMInt32TypeInContext(gallivm->context);
 
-       LLVMValueRef so_param =
-               LLVMGetParam(shader->radeon_bld.main_fn,
-                            shader->param_streamout_config);
-
        /* Get bits [22:16], i.e. (so_param >> 16) & 127; */
        LLVMValueRef so_vtx_count =
-               LLVMBuildAnd(builder,
-                            LLVMBuildLShr(builder, so_param,
-                                          LLVMConstInt(i32, 16, 0), ""),
-                            LLVMConstInt(i32, 127, 0), "");
+               unpack_param(shader, shader->param_streamout_config, 16, 7);
 
        LLVMValueRef tid = build_intrinsic(builder, "llvm.SI.tid", i32,
                                           NULL, 0, LLVMReadNoneAttribute);