amd/common: lower bitfield_insert to bfm & bitfield_select

Reviewed-by: Connor Abbott <cwabbott0@gmail.com>

diff --git a/src/amd/common/ac_nir_to_llvm.c b/src/amd/common/ac_nir_to_llvm.c
index dffaeed..9b6e65d 100644 (file)
--- a/src/amd/common/ac_nir_to_llvm.c
+++ b/src/amd/common/ac_nir_to_llvm.c
@@ -455,34 +455,30 @@ static LLVMValueRef emit_bitfield_extract(struct ac_llvm_context *ctx,
        return result;
 }
 
-static LLVMValueRef emit_bitfield_insert(struct ac_llvm_context *ctx,
-                                        LLVMValueRef src0, LLVMValueRef src1,
-                                        LLVMValueRef src2, LLVMValueRef src3)
+static LLVMValueRef emit_bfm(struct ac_llvm_context *ctx,
+                            LLVMValueRef bits, LLVMValueRef offset)
 {
-       LLVMValueRef bfi_args[3], result;
-
-       bfi_args[0] = LLVMBuildShl(ctx->builder,
-                                  LLVMBuildSub(ctx->builder,
-                                               LLVMBuildShl(ctx->builder,
-                                                            ctx->i32_1,
-                                                            src3, ""),
-                                               ctx->i32_1, ""),
-                                  src2, "");
-       bfi_args[1] = LLVMBuildShl(ctx->builder, src1, src2, "");
-       bfi_args[2] = src0;
-
-       LLVMValueRef icond = LLVMBuildICmp(ctx->builder, LLVMIntEQ, src3, LLVMConstInt(ctx->i32, 32, false), "");
+       /* mask = ((1 << bits) - 1) << offset */
+       return LLVMBuildShl(ctx->builder,
+                           LLVMBuildSub(ctx->builder,
+                                        LLVMBuildShl(ctx->builder,
+                                                     ctx->i32_1,
+                                                     bits, ""),
+                                        ctx->i32_1, ""),
+                           offset, "");
+}
 
+static LLVMValueRef emit_bitfield_select(struct ac_llvm_context *ctx,
+                                        LLVMValueRef mask, LLVMValueRef insert,
+                                        LLVMValueRef base)
+{
        /* Calculate:
-        *   (arg0 & arg1) | (~arg0 & arg2) = arg2 ^ (arg0 & (arg1 ^ arg2)
+        *   (mask & insert) | (~mask & base) = base ^ (mask & (insert ^ base))
         * Use the right-hand side, which the LLVM backend can convert to V_BFI.
         */
-       result = LLVMBuildXor(ctx->builder, bfi_args[2],
-                             LLVMBuildAnd(ctx->builder, bfi_args[0],
-                                          LLVMBuildXor(ctx->builder, bfi_args[1], bfi_args[2], ""), ""), "");
-
-       result = LLVMBuildSelect(ctx->builder, icond, src1, result, "");
-       return result;
+       return LLVMBuildXor(ctx->builder, base,
+                           LLVMBuildAnd(ctx->builder, mask,
+                                        LLVMBuildXor(ctx->builder, insert, base, ""), ""), "");
 }
 
 static LLVMValueRef emit_pack_half_2x16(struct ac_llvm_context *ctx,
@@ -835,15 +831,18 @@ static void visit_alu(struct ac_nir_context *ctx, const nir_alu_instr *instr)
                else
                        result = ac_build_intrinsic(&ctx->ac, "llvm.amdgcn.ldexp.f64", ctx->ac.f64, src, 2, AC_FUNC_ATTR_READNONE);
                break;
+       case nir_op_bfm:
+               result = emit_bfm(&ctx->ac, src[0], src[1]);
+               break;
+       case nir_op_bitfield_select:
+               result = emit_bitfield_select(&ctx->ac, src[0], src[1], src[2]);
+               break;
        case nir_op_ibitfield_extract:
                result = emit_bitfield_extract(&ctx->ac, true, src);
                break;
        case nir_op_ubitfield_extract:
                result = emit_bitfield_extract(&ctx->ac, false, src);
                break;
-       case nir_op_bitfield_insert:
-               result = emit_bitfield_insert(&ctx->ac, src[0], src[1], src[2], src[3]);
-               break;
        case nir_op_bitfield_reverse:
                result = ac_build_bitfield_reverse(&ctx->ac, src[0]);
                break;

diff --git a/src/amd/vulkan/radv_shader.c b/src/amd/vulkan/radv_shader.c
index c3bbf3f..3452a0b 100644 (file)
--- a/src/amd/vulkan/radv_shader.c
+++ b/src/amd/vulkan/radv_shader.c
@@ -58,6 +58,7 @@ static const struct nir_shader_compiler_options nir_options = {
        .lower_device_index_to_zero = true,
        .lower_fsat = true,
        .lower_fdiv = true,
+       .lower_bitfield_insert_to_bitfield_select = true,
        .lower_sub = true,
        .lower_pack_snorm_2x16 = true,
        .lower_pack_snorm_4x8 = true,

diff --git a/src/gallium/drivers/radeonsi/si_get.c b/src/gallium/drivers/radeonsi/si_get.c
index 0c561e7..b7c7f1a 100644 (file)
--- a/src/gallium/drivers/radeonsi/si_get.c
+++ b/src/gallium/drivers/radeonsi/si_get.c
@@ -487,6 +487,7 @@ static const struct nir_shader_compiler_options nir_options = {
        .lower_flrp64 = true,
        .lower_fsat = true,
        .lower_fdiv = true,
+       .lower_bitfield_insert_to_bitfield_select = true,
        .lower_sub = true,
        .lower_ffma = true,
        .lower_fmod = true,