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ac/nir: Implement LLVM9 64-bit buffer compare & exchange. 

LLVM 9 does not have a 64-bit buffer compswap intrinsic, so this
extracts the ptr, does a bound check and then uses a cmpxchg LLVM
instruction.

Not ideal, but the earliest release we're going to get a proper
intrinsic is LLVM 10.

Reviewed-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
This commit is contained in:
Bas Nieuwenhuizen 2019-08-02 12:01:34 +02:00
parent 73274c9ec2
commit a17f2206d3
1 changed files with 64 additions and 4 deletions
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68
src/amd/common/ac_nir_to_llvm.c
View File

@ -1638,13 +1638,64 @@ static void visit_store_ssbo(struct ac_nir_context *ctx,
}
}
static LLVMValueRef emit_ssbo_comp_swap_64(struct ac_nir_context *ctx,
LLVMValueRef descriptor,
LLVMValueRef offset,
LLVMValueRef compare,
LLVMValueRef exchange)
{
LLVMValueRef size = ac_llvm_extract_elem(&ctx->ac, descriptor, 2);
LLVMValueRef cond = LLVMBuildICmp(ctx->ac.builder, LLVMIntULT, offset, size, "");
LLVMBasicBlockRef start_block = LLVMGetInsertBlock(ctx->ac.builder);
ac_build_ifcc(&ctx->ac, cond, -1);
LLVMBasicBlockRef then_block = LLVMGetInsertBlock(ctx->ac.builder);
LLVMValueRef ptr_parts[2] = {
ac_llvm_extract_elem(&ctx->ac, descriptor, 0),
LLVMBuildAnd(ctx->ac.builder,
ac_llvm_extract_elem(&ctx->ac, descriptor, 1),
LLVMConstInt(ctx->ac.i32, 65535, 0), "")
};
ptr_parts[1] = LLVMBuildTrunc(ctx->ac.builder, ptr_parts[1], ctx->ac.i16, "");
ptr_parts[1] = LLVMBuildSExt(ctx->ac.builder, ptr_parts[1], ctx->ac.i32, "");
offset = LLVMBuildZExt(ctx->ac.builder, offset, ctx->ac.i64, "");
LLVMValueRef ptr = ac_build_gather_values(&ctx->ac, ptr_parts, 2);
ptr = LLVMBuildBitCast(ctx->ac.builder, ptr, ctx->ac.i64, "");
ptr = LLVMBuildAdd(ctx->ac.builder, ptr, offset, "");
ptr = LLVMBuildIntToPtr(ctx->ac.builder, ptr, LLVMPointerType(ctx->ac.i64, AC_ADDR_SPACE_GLOBAL), "");
LLVMValueRef result = ac_build_atomic_cmp_xchg(&ctx->ac, ptr, compare, exchange, "singlethread-one-as");
result = LLVMBuildExtractValue(ctx->ac.builder, result, 0, "");
ac_build_endif(&ctx->ac, -1);
LLVMBasicBlockRef incoming_blocks[2] = {
start_block,
then_block,
};
LLVMValueRef incoming_values[2] = {
LLVMConstInt(ctx->ac.i64, 0, 0),
result,
};
LLVMValueRef ret = LLVMBuildPhi(ctx->ac.builder, ctx->ac.i64, "");
LLVMAddIncoming(ret, incoming_values, incoming_blocks, 2);
return ret;
}
static LLVMValueRef visit_atomic_ssbo(struct ac_nir_context *ctx,
const nir_intrinsic_instr *instr)
{
LLVMTypeRef return_type = LLVMTypeOf(get_src(ctx, instr->src[2]));
const char *op;
char name[64], type[8];
LLVMValueRef params[6];
LLVMValueRef params[6], descriptor;
int arg_count = 0;
switch (instr->intrinsic) {
@ -1682,13 +1733,22 @@ static LLVMValueRef visit_atomic_ssbo(struct ac_nir_context *ctx,
abort();
}
descriptor = ctx->abi->load_ssbo(ctx->abi,
get_src(ctx, instr->src[0]),
true);
if (instr->intrinsic == nir_intrinsic_ssbo_atomic_comp_swap &&
return_type == ctx->ac.i64) {
return emit_ssbo_comp_swap_64(ctx, descriptor,
get_src(ctx, instr->src[1]),
get_src(ctx, instr->src[2]),
get_src(ctx, instr->src[3]));
}
if (instr->intrinsic == nir_intrinsic_ssbo_atomic_comp_swap) {
params[arg_count++] = ac_llvm_extract_elem(&ctx->ac, get_src(ctx, instr->src[3]), 0);
}
params[arg_count++] = ac_llvm_extract_elem(&ctx->ac, get_src(ctx, instr->src[2]), 0);
params[arg_count++] = ctx->abi->load_ssbo(ctx->abi,
get_src(ctx, instr->src[0]),
true);
params[arg_count++] = descriptor;
if (HAVE_LLVM >= 0x900) {
/* XXX: The new raw/struct atomic intrinsics are buggy with