static LLVMValueRef
CreateFibFunction(LLVMModuleRef M, LLVMContextRef Context)
{
LLVMBuilderRef B = LLVMCreateBuilderInContext(Context);
// Create the fib function and insert it into module M. This function is said
// to return an int and take an int parameter.
LLVMTypeRef ParamTypes[] = {LLVMInt32TypeInContext(Context)};
LLVMTypeRef ReturnType = LLVMInt32TypeInContext(Context);
LLVMTypeRef FunctionTy = LLVMFunctionType(ReturnType, ParamTypes, 1, 0);
LLVMValueRef FibF = LLVMAddFunction(M, "fib", FunctionTy);
// Add a basic block to the function.
LLVMBasicBlockRef BB = LLVMAppendBasicBlockInContext(Context, FibF, "EntryBlock");
// Get pointers to the constants.
LLVMValueRef One = LLVMConstInt(LLVMInt32TypeInContext(Context), 1, 0);
LLVMValueRef Two = LLVMConstInt(LLVMInt32TypeInContext(Context), 2, 0);
// Get pointer to the integer argument of the add1 function...
LLVMValueRef ArgX = LLVMGetFirstParam(FibF); // Get the arg.
LLVMSetValueName(ArgX, "AnArg"); // Give it a nice symbolic name for fun.
// Create the true_block.
LLVMBasicBlockRef RetBB = LLVMAppendBasicBlockInContext(Context, FibF, "return");
// Create an exit block.
LLVMBasicBlockRef RecurseBB = LLVMAppendBasicBlockInContext(Context, FibF, "recurse");
// Create the "if (arg <= 2) goto exitbb"
LLVMPositionBuilderAtEnd(B, BB);
LLVMValueRef CondInst = LLVMBuildICmp(B, LLVMIntSLE, ArgX, Two, "cond");
LLVMBuildCondBr(B, CondInst, RetBB, RecurseBB);
// Create: ret int 1
LLVMPositionBuilderAtEnd(B, RetBB);
LLVMBuildRet(B, One);
// create fib(x-1)
LLVMPositionBuilderAtEnd(B, RecurseBB);
LLVMValueRef Sub = LLVMBuildSub(B, ArgX, One, "arg");
LLVMValueRef CallFibX1 = LLVMBuildCall(B, FibF, &Sub, 1, "fibx1");
LLVMSetTailCall(CallFibX1, 1);
// create fib(x-2)
LLVMPositionBuilderAtEnd(B, RecurseBB);
Sub = LLVMBuildSub(B, ArgX, Two, "arg");
LLVMValueRef CallFibX2 = LLVMBuildCall(B, FibF, &Sub, 1, "fibx2");
LLVMSetTailCall(CallFibX2, 1);
// fib(x-1)+fib(x-2)
LLVMPositionBuilderAtEnd(B, RecurseBB);
LLVMValueRef Sum = LLVMBuildAdd(B, CallFibX1, CallFibX2, "addresult");
// Create the return instruction and add it to the basic block
LLVMPositionBuilderAtEnd(B, RecurseBB);
LLVMBuildRet(B, Sum);
return FibF;
}
void
lp_build_exp2_approx(struct lp_build_context *bld,
LLVMValueRef x,
LLVMValueRef *p_exp2_int_part,
LLVMValueRef *p_frac_part,
LLVMValueRef *p_exp2)
{
const struct lp_type type = bld->type;
LLVMTypeRef vec_type = lp_build_vec_type(type);
LLVMTypeRef int_vec_type = lp_build_int_vec_type(type);
LLVMValueRef ipart = NULL;
LLVMValueRef fpart = NULL;
LLVMValueRef expipart = NULL;
LLVMValueRef expfpart = NULL;
LLVMValueRef res = NULL;
if(p_exp2_int_part || p_frac_part || p_exp2) {
/* TODO: optimize the constant case */
if(LLVMIsConstant(x))
debug_printf("%s: inefficient/imprecise constant arithmetic\n",
__FUNCTION__);
assert(type.floating && type.width == 32);
x = lp_build_min(bld, x, lp_build_const_scalar(type, 129.0));
x = lp_build_max(bld, x, lp_build_const_scalar(type, -126.99999));
/* ipart = int(x - 0.5) */
ipart = LLVMBuildSub(bld->builder, x, lp_build_const_scalar(type, 0.5f), "");
ipart = LLVMBuildFPToSI(bld->builder, ipart, int_vec_type, "");
/* fpart = x - ipart */
fpart = LLVMBuildSIToFP(bld->builder, ipart, vec_type, "");
fpart = LLVMBuildSub(bld->builder, x, fpart, "");
}
if(p_exp2_int_part || p_exp2) {
/* expipart = (float) (1 << ipart) */
expipart = LLVMBuildAdd(bld->builder, ipart, lp_build_int_const_scalar(type, 127), "");
expipart = LLVMBuildShl(bld->builder, expipart, lp_build_int_const_scalar(type, 23), "");
expipart = LLVMBuildBitCast(bld->builder, expipart, vec_type, "");
}
if(p_exp2) {
expfpart = lp_build_polynomial(bld, fpart, lp_build_exp2_polynomial,
Elements(lp_build_exp2_polynomial));
res = LLVMBuildMul(bld->builder, expipart, expfpart, "");
}
if(p_exp2_int_part)
*p_exp2_int_part = expipart;
if(p_frac_part)
*p_frac_part = fpart;
if(p_exp2)
*p_exp2 = res;
}
/*
* Helper for building packed ddx/ddy vector for one coord (scalar per quad
* values). The vector will look like this (8-wide):
* ds1dx ds1dy dt1dx dt1dy ds2dx ds2dy dt2dx dt2dy
* This only needs 2 (v)shufps.
*/
LLVMValueRef
lp_build_packed_ddx_ddy_twocoord(struct lp_build_context *bld,
LLVMValueRef a, LLVMValueRef b)
{
struct gallivm_state *gallivm = bld->gallivm;
LLVMBuilderRef builder = gallivm->builder;
LLVMValueRef shuffles1[LP_MAX_VECTOR_LENGTH/4];
LLVMValueRef shuffles2[LP_MAX_VECTOR_LENGTH/4];
LLVMValueRef vec1, vec2;
unsigned length, num_quads, i;
/* XXX: do hsub version */
length = bld->type.length;
num_quads = length / 4;
for (i = 0; i < num_quads; i++) {
unsigned s1 = 4 * i;
unsigned s2 = 4 * i + length;
shuffles1[4*i + 0] = lp_build_const_int32(gallivm, LP_BLD_QUAD_TOP_LEFT + s1);
shuffles1[4*i + 1] = lp_build_const_int32(gallivm, LP_BLD_QUAD_TOP_LEFT + s1);
shuffles1[4*i + 2] = lp_build_const_int32(gallivm, LP_BLD_QUAD_TOP_LEFT + s2);
shuffles1[4*i + 3] = lp_build_const_int32(gallivm, LP_BLD_QUAD_TOP_LEFT + s2);
shuffles2[4*i + 0] = lp_build_const_int32(gallivm, LP_BLD_QUAD_TOP_RIGHT + s1);
shuffles2[4*i + 1] = lp_build_const_int32(gallivm, LP_BLD_QUAD_BOTTOM_LEFT + s1);
shuffles2[4*i + 2] = lp_build_const_int32(gallivm, LP_BLD_QUAD_TOP_RIGHT + s2);
shuffles2[4*i + 3] = lp_build_const_int32(gallivm, LP_BLD_QUAD_BOTTOM_LEFT + s2);
}
vec1 = LLVMBuildShuffleVector(builder, a, b,
LLVMConstVector(shuffles1, length), "");
vec2 = LLVMBuildShuffleVector(builder, a, b,
LLVMConstVector(shuffles2, length), "");
if (bld->type.floating)
return LLVMBuildFSub(builder, vec2, vec1, "ddxddyddxddy");
else
return LLVMBuildSub(builder, vec2, vec1, "ddxddyddxddy");
}
/**
* Special case for converting clamped IEEE-754 floats to unsigned norms.
*
* The mathematical voodoo below may seem excessive but it is actually
* paramount we do it this way for several reasons. First, there is no single
* precision FP to unsigned integer conversion Intel SSE instruction. Second,
* secondly, even if there was, since the FP's mantissa takes only a fraction
* of register bits the typically scale and cast approach would require double
* precision for accurate results, and therefore half the throughput
*
* Although the result values can be scaled to an arbitrary bit width specified
* by dst_width, the actual result type will have the same width.
*/
LLVMValueRef
lp_build_clamped_float_to_unsigned_norm(LLVMBuilderRef builder,
struct lp_type src_type,
unsigned dst_width,
LLVMValueRef src)
{
LLVMTypeRef int_vec_type = lp_build_int_vec_type(src_type);
LLVMValueRef res;
unsigned mantissa;
unsigned n;
unsigned long long ubound;
unsigned long long mask;
double scale;
double bias;
assert(src_type.floating);
mantissa = lp_mantissa(src_type);
/* We cannot carry more bits than the mantissa */
n = MIN2(mantissa, dst_width);
/* This magic coefficients will make the desired result to appear in the
* lowest significant bits of the mantissa.
*/
ubound = ((unsigned long long)1 << n);
mask = ubound - 1;
scale = (double)mask/ubound;
bias = (double)((unsigned long long)1 << (mantissa - n));
res = LLVMBuildMul(builder, src, lp_build_const_scalar(src_type, scale), "");
res = LLVMBuildAdd(builder, res, lp_build_const_scalar(src_type, bias), "");
res = LLVMBuildBitCast(builder, res, int_vec_type, "");
if(dst_width > n) {
int shift = dst_width - n;
res = LLVMBuildShl(builder, res, lp_build_int_const_scalar(src_type, shift), "");
/* TODO: Fill in the empty lower bits for additional precision? */
#if 0
{
LLVMValueRef msb;
msb = LLVMBuildLShr(builder, res, lp_build_int_const_scalar(src_type, dst_width - 1), "");
msb = LLVMBuildShl(builder, msb, lp_build_int_const_scalar(src_type, shift), "");
msb = LLVMBuildSub(builder, msb, lp_build_int_const_scalar(src_type, 1), "");
res = LLVMBuildOr(builder, res, msb, "");
}
#elif 0
while(shift > 0) {
res = LLVMBuildOr(builder, res, LLVMBuildLShr(builder, res, lp_build_int_const_scalar(src_type, n), ""), "");
shift -= n;
n *= 2;
}
#endif
}
else
res = LLVMBuildAnd(builder, res, lp_build_int_const_scalar(src_type, mask), "");
return res;
}
/* Find the last bit set. */
static void emit_umsb(const struct lp_build_tgsi_action *action,
struct lp_build_tgsi_context *bld_base,
struct lp_build_emit_data *emit_data)
{
struct gallivm_state *gallivm = bld_base->base.gallivm;
LLVMBuilderRef builder = gallivm->builder;
LLVMValueRef args[2] = {
emit_data->args[0],
/* Don't generate code for handling zero: */
LLVMConstInt(LLVMInt1TypeInContext(gallivm->context), 1, 0)
};
LLVMValueRef msb =
lp_build_intrinsic(builder, "llvm.ctlz.i32",
emit_data->dst_type, args, ARRAY_SIZE(args),
LLVMReadNoneAttribute);
/* The HW returns the last bit index from MSB, but TGSI wants
* the index from LSB. Invert it by doing "31 - msb". */
msb = LLVMBuildSub(builder, lp_build_const_int32(gallivm, 31),
msb, "");
/* Check for zero: */
emit_data->output[emit_data->chan] =
LLVMBuildSelect(builder,
LLVMBuildICmp(builder, LLVMIntEQ, args[0],
bld_base->uint_bld.zero, ""),
lp_build_const_int32(gallivm, -1), msb, "");
}
/* Find the last bit opposite of the sign bit. */
static void emit_imsb(const struct lp_build_tgsi_action *action,
struct lp_build_tgsi_context *bld_base,
struct lp_build_emit_data *emit_data)
{
struct gallivm_state *gallivm = bld_base->base.gallivm;
LLVMBuilderRef builder = gallivm->builder;
LLVMValueRef arg = emit_data->args[0];
LLVMValueRef msb =
lp_build_intrinsic(builder, "llvm.AMDGPU.flbit.i32",
emit_data->dst_type, &arg, 1,
LLVMReadNoneAttribute);
/* The HW returns the last bit index from MSB, but TGSI wants
* the index from LSB. Invert it by doing "31 - msb". */
msb = LLVMBuildSub(builder, lp_build_const_int32(gallivm, 31),
msb, "");
/* If arg == 0 || arg == -1 (0xffffffff), return -1. */
LLVMValueRef all_ones = lp_build_const_int32(gallivm, -1);
LLVMValueRef cond =
LLVMBuildOr(builder,
LLVMBuildICmp(builder, LLVMIntEQ, arg,
bld_base->uint_bld.zero, ""),
LLVMBuildICmp(builder, LLVMIntEQ, arg,
all_ones, ""), "");
emit_data->output[emit_data->chan] =
LLVMBuildSelect(builder, cond, all_ones, msb, "");
}
/*
* Helper for building packed ddx/ddy vector for one coord (scalar per quad
* values). The vector will look like this (8-wide):
* dr1dx _____ -dr1dy _____ dr2dx _____ -dr2dy _____
* This only requires one shuffle instead of two for more straightforward packing.
*/
LLVMValueRef
lp_build_packed_ddx_ddy_onecoord(struct lp_build_context *bld,
LLVMValueRef a)
{
struct gallivm_state *gallivm = bld->gallivm;
LLVMBuilderRef builder = gallivm->builder;
LLVMValueRef vec1, vec2;
/* use aos swizzle helper */
static const unsigned char swizzle1[] = { /* no-op swizzle */
LP_BLD_QUAD_TOP_LEFT, LP_BLD_SWIZZLE_DONTCARE,
LP_BLD_QUAD_BOTTOM_LEFT, LP_BLD_SWIZZLE_DONTCARE
};
static const unsigned char swizzle2[] = {
LP_BLD_QUAD_TOP_RIGHT, LP_BLD_SWIZZLE_DONTCARE,
LP_BLD_QUAD_TOP_LEFT, LP_BLD_SWIZZLE_DONTCARE
};
vec1 = lp_build_swizzle_aos(bld, a, swizzle1);
vec2 = lp_build_swizzle_aos(bld, a, swizzle2);
if (bld->type.floating)
return LLVMBuildFSub(builder, vec2, vec1, "ddxddy");
else
return LLVMBuildSub(builder, vec2, vec1, "ddxddy");
}
LLVMValueRef gen_sub(struct node *ast)
{
return LLVMBuildSub(builder,
codegen(ast->one),
codegen(ast->two),
"");
}
LLVMValueRef
ac_build_imsb(struct ac_llvm_context *ctx,
LLVMValueRef arg,
LLVMTypeRef dst_type)
{
const char *intr_name = (HAVE_LLVM < 0x0400) ? "llvm.AMDGPU.flbit.i32" :
"llvm.amdgcn.sffbh.i32";
LLVMValueRef msb = ac_build_intrinsic(ctx, intr_name,
dst_type, &arg, 1,
AC_FUNC_ATTR_READNONE);
/* The HW returns the last bit index from MSB, but NIR/TGSI wants
* the index from LSB. Invert it by doing "31 - msb". */
msb = LLVMBuildSub(ctx->builder, LLVMConstInt(ctx->i32, 31, false),
msb, "");
LLVMValueRef all_ones = LLVMConstInt(ctx->i32, -1, true);
LLVMValueRef cond = LLVMBuildOr(ctx->builder,
LLVMBuildICmp(ctx->builder, LLVMIntEQ,
arg, LLVMConstInt(ctx->i32, 0, 0), ""),
LLVMBuildICmp(ctx->builder, LLVMIntEQ,
arg, all_ones, ""), "");
return LLVMBuildSelect(ctx->builder, cond, all_ones, msb, "");
}
struct LLVMOpaqueValue *bllvm_compile_rirbop(const struct rir_expression *expr,
struct llvm_traversal_ctx *ctx)
{
LLVMValueRef ret;
LLVMValueRef left = bllvm_value_from_rir_value_or_die(expr->binaryop.a, ctx);
LLVMValueRef right = bllvm_value_from_rir_value_or_die(expr->binaryop.b, ctx);
switch(expr->type) {
case RIR_EXPRESSION_ADD:
ret = LLVMBuildAdd(ctx->builder, left, right, "");
break;
case RIR_EXPRESSION_SUB:
ret = LLVMBuildSub(ctx->builder, left, right, "");
break;
case RIR_EXPRESSION_MUL:
ret = LLVMBuildMul(ctx->builder, left, right, "");
break;
case RIR_EXPRESSION_DIV:
ret = LLVMBuildUDiv(ctx->builder, left, right, "");
break;
default:
RF_CRITICAL_FAIL("Should never get anything other than binaryop here");
break;
}
return ret;
}
/*
* To be able to handle multiple quads at once in texture sampling and
* do lod calculations per quad, it is necessary to get the per-quad
* derivatives into the lp_build_rho function.
* For 8-wide vectors the packed derivative values for 3 coords would
* look like this, this scales to a arbitrary (multiple of 4) vector size:
* ds1dx ds1dy dt1dx dt1dy ds2dx ds2dy dt2dx dt2dy
* dr1dx dr1dy _____ _____ dr2dx dr2dy _____ _____
* The second vector will be unused for 1d and 2d textures.
*/
LLVMValueRef
lp_build_packed_ddx_ddy_onecoord(struct lp_build_context *bld,
LLVMValueRef a)
{
struct gallivm_state *gallivm = bld->gallivm;
LLVMBuilderRef builder = gallivm->builder;
LLVMValueRef vec1, vec2;
/* same packing as _twocoord, but can use aos swizzle helper */
/*
* XXX could make swizzle1 a noop swizzle by using right top/bottom
* pair for ddy
*/
static const unsigned char swizzle1[] = {
LP_BLD_QUAD_TOP_LEFT, LP_BLD_QUAD_TOP_LEFT,
LP_BLD_SWIZZLE_DONTCARE, LP_BLD_SWIZZLE_DONTCARE
};
static const unsigned char swizzle2[] = {
LP_BLD_QUAD_TOP_RIGHT, LP_BLD_QUAD_BOTTOM_LEFT,
LP_BLD_SWIZZLE_DONTCARE, LP_BLD_SWIZZLE_DONTCARE
};
vec1 = lp_build_swizzle_aos(bld, a, swizzle1);
vec2 = lp_build_swizzle_aos(bld, a, swizzle2);
if (bld->type.floating)
return LLVMBuildFSub(builder, vec2, vec1, "ddxddy");
else
return LLVMBuildSub(builder, vec2, vec1, "ddxddy");
}
LLVMValueRef gen_predec(struct node *ast)
{
LLVMValueRef result;
result = LLVMBuildSub(builder,
codegen(ast->one),
CONST(1),
"");
check_store(result, lvalue(ast->one));
return result;
}
LLVMValueRef gen_postdec(struct node *ast)
{
LLVMValueRef orig, result;
orig = codegen(ast->one);
result = LLVMBuildSub(builder,
orig,
CONST(1),
"");
check_store(result, lvalue(ast->one));
return orig;
}
/**
* Inverse of lp_build_clamped_float_to_unsigned_norm above.
*/
LLVMValueRef
lp_build_unsigned_norm_to_float(LLVMBuilderRef builder,
unsigned src_width,
struct lp_type dst_type,
LLVMValueRef src)
{
LLVMTypeRef vec_type = lp_build_vec_type(dst_type);
LLVMTypeRef int_vec_type = lp_build_int_vec_type(dst_type);
LLVMValueRef bias_;
LLVMValueRef res;
unsigned mantissa;
unsigned n;
unsigned long long ubound;
unsigned long long mask;
double scale;
double bias;
mantissa = lp_mantissa(dst_type);
n = MIN2(mantissa, src_width);
ubound = ((unsigned long long)1 << n);
mask = ubound - 1;
scale = (double)ubound/mask;
bias = (double)((unsigned long long)1 << (mantissa - n));
res = src;
if(src_width > mantissa) {
int shift = src_width - mantissa;
res = LLVMBuildLShr(builder, res, lp_build_int_const_scalar(dst_type, shift), "");
}
bias_ = lp_build_const_scalar(dst_type, bias);
res = LLVMBuildOr(builder,
res,
LLVMBuildBitCast(builder, bias_, int_vec_type, ""), "");
res = LLVMBuildBitCast(builder, res, vec_type, "");
res = LLVMBuildSub(builder, res, bias_, "");
res = LLVMBuildMul(builder, res, lp_build_const_scalar(dst_type, scale), "");
return res;
}
static LLVMValueRef
translateIntBinOp(NodeKind Op, LLVMValueRef ValueE1, LLVMValueRef ValueE2) {
switch (Op) {
case OrOp: return LLVMBuildOr (Builder, ValueE1, ValueE2, "");
case AndOp: return LLVMBuildAnd(Builder, ValueE1, ValueE2, "");
case SumOp: return LLVMBuildAdd(Builder, ValueE1, ValueE2, "");
case SubOp: return LLVMBuildSub(Builder, ValueE1, ValueE2, "");
case MultOp: return LLVMBuildMul(Builder, ValueE1, ValueE2, "");
case DivOp: return LLVMBuildSDiv(Builder, ValueE1, ValueE2, "");
case LtOp: return LLVMBuildICmp(Builder, LLVMIntSLT, ValueE1, ValueE2, "");
case LeOp: return LLVMBuildICmp(Builder, LLVMIntSLE, ValueE1, ValueE2, "");
case GtOp: return LLVMBuildICmp(Builder, LLVMIntSGT, ValueE1, ValueE2, "");
case GeOp: return LLVMBuildICmp(Builder, LLVMIntSGE, ValueE1, ValueE2, "");
case EqOp: return LLVMBuildICmp(Builder, LLVMIntEQ, ValueE1, ValueE2, "");
case DiffOp: return LLVMBuildICmp(Builder, LLVMIntNE, ValueE1, ValueE2, "");
default: return NULL;
}
}
static inline LLVMValueRef LLVM_visit(ASTNode *node, LLVMBuilderRef builder) {
switch(node->type) {
case AST_BINARY_OP: {
ASTBinaryOp *binary_op = (ASTBinaryOp*)node;
LLVMValueRef a = LLVM_visit(binary_op->lhs, builder);
LLVMValueRef b = LLVM_visit(binary_op->rhs, builder);
switch(binary_op->op) {
case '+': return LLVMBuildAdd(builder, a, b, "a + b");
case '-': return LLVMBuildSub(builder, a, b, "a - b");
case '*': return LLVMBuildMul(builder, a, b, "a * b");
case '/': return LLVMBuildSDiv(builder, a, b, "a / b");
}
}
case AST_INT: {
return LLVMConstInt(LLVMInt32Type(), ((ASTInt*)node)->value, 0);
}
}
}
/**
* Generate a - b
*/
LLVMValueRef
lp_build_sub(struct lp_build_context *bld,
LLVMValueRef a,
LLVMValueRef b)
{
const struct lp_type type = bld->type;
LLVMValueRef res;
if(b == bld->zero)
return a;
if(a == bld->undef || b == bld->undef)
return bld->undef;
if(a == b)
return bld->zero;
if(bld->type.norm) {
const char *intrinsic = NULL;
if(b == bld->one)
return bld->zero;
if(util_cpu_caps.has_sse2 &&
type.width * type.length == 128 &&
!type.floating && !type.fixed) {
if(type.width == 8)
intrinsic = type.sign ? "llvm.x86.sse2.psubs.b" : "llvm.x86.sse2.psubus.b";
if(type.width == 16)
intrinsic = type.sign ? "llvm.x86.sse2.psubs.w" : "llvm.x86.sse2.psubus.w";
}
if(intrinsic)
return lp_build_intrinsic_binary(bld->builder, intrinsic, lp_build_vec_type(bld->type), a, b);
}
if(LLVMIsConstant(a) && LLVMIsConstant(b))
res = LLVMConstSub(a, b);
else
res = LLVMBuildSub(bld->builder, a, b, "");
if(bld->type.norm && (bld->type.floating || bld->type.fixed))
res = lp_build_max_simple(bld, res, bld->zero);
return res;
}
static void emit_bfi(const struct lp_build_tgsi_action *action,
struct lp_build_tgsi_context *bld_base,
struct lp_build_emit_data *emit_data)
{
struct gallivm_state *gallivm = bld_base->base.gallivm;
LLVMBuilderRef builder = gallivm->builder;
LLVMValueRef bfi_args[3];
LLVMValueRef bfi_sm5;
LLVMValueRef cond;
// Calculate the bitmask: (((1 << src3) - 1) << src2
bfi_args[0] = LLVMBuildShl(builder,
LLVMBuildSub(builder,
LLVMBuildShl(builder,
bld_base->int_bld.one,
emit_data->args[3], ""),
bld_base->int_bld.one, ""),
emit_data->args[2], "");
bfi_args[1] = LLVMBuildShl(builder, emit_data->args[1],
emit_data->args[2], "");
bfi_args[2] = emit_data->args[0];
/* Calculate:
* (arg0 & arg1) | (~arg0 & arg2) = arg2 ^ (arg0 & (arg1 ^ arg2)
* Use the right-hand side, which the LLVM backend can convert to V_BFI.
*/
bfi_sm5 =
LLVMBuildXor(builder, bfi_args[2],
LLVMBuildAnd(builder, bfi_args[0],
LLVMBuildXor(builder, bfi_args[1], bfi_args[2],
""), ""), "");
/* Since shifts of >= 32 bits are undefined in LLVM IR, the backend
* uses the convenient V_BFI lowering for the above, which follows SM5
* and disagrees with GLSL semantics when bits (src3) is 32.
*/
cond = LLVMBuildICmp(builder, LLVMIntUGE, emit_data->args[3],
lp_build_const_int32(gallivm, 32), "");
emit_data->output[emit_data->chan] =
LLVMBuildSelect(builder, cond, emit_data->args[1], bfi_sm5, "");
}
/**
* Generate 1 - a, or ~a depending on bld->type.
*/
LLVMValueRef
lp_build_comp(struct lp_build_context *bld,
LLVMValueRef a)
{
const struct lp_type type = bld->type;
if(a == bld->one)
return bld->zero;
if(a == bld->zero)
return bld->one;
if(type.norm && !type.floating && !type.fixed && !type.sign) {
if(LLVMIsConstant(a))
return LLVMConstNot(a);
else
return LLVMBuildNot(bld->builder, a, "");
}
if(LLVMIsConstant(a))
return LLVMConstSub(bld->one, a);
else
return LLVMBuildSub(bld->builder, bld->one, a, "");
}
LLVMValueRef
ac_build_umsb(struct ac_llvm_context *ctx,
LLVMValueRef arg,
LLVMTypeRef dst_type)
{
LLVMValueRef args[2] = {
arg,
LLVMConstInt(ctx->i1, 1, 0),
};
LLVMValueRef msb = ac_build_intrinsic(ctx, "llvm.ctlz.i32",
dst_type, args, ARRAY_SIZE(args),
AC_FUNC_ATTR_READNONE);
/* The HW returns the last bit index from MSB, but TGSI/NIR wants
* the index from LSB. Invert it by doing "31 - msb". */
msb = LLVMBuildSub(ctx->builder, LLVMConstInt(ctx->i32, 31, false),
msb, "");
/* check for zero */
return LLVMBuildSelect(ctx->builder,
LLVMBuildICmp(ctx->builder, LLVMIntEQ, arg,
LLVMConstInt(ctx->i32, 0, 0), ""),
LLVMConstInt(ctx->i32, -1, true), msb, "");
}
static INLINE void
yuv_to_rgb_soa(struct gallivm_state *gallivm,
unsigned n,
LLVMValueRef y, LLVMValueRef u, LLVMValueRef v,
LLVMValueRef *r, LLVMValueRef *g, LLVMValueRef *b)
{
LLVMBuilderRef builder = gallivm->builder;
struct lp_type type;
struct lp_build_context bld;
LLVMValueRef c0;
LLVMValueRef c8;
LLVMValueRef c16;
LLVMValueRef c128;
LLVMValueRef c255;
LLVMValueRef cy;
LLVMValueRef cug;
LLVMValueRef cub;
LLVMValueRef cvr;
LLVMValueRef cvg;
memset(&type, 0, sizeof type);
type.sign = TRUE;
type.width = 32;
type.length = n;
lp_build_context_init(&bld, gallivm, type);
assert(lp_check_value(type, y));
assert(lp_check_value(type, u));
assert(lp_check_value(type, v));
/*
* Constants
*/
c0 = lp_build_const_int_vec(gallivm, type, 0);
c8 = lp_build_const_int_vec(gallivm, type, 8);
c16 = lp_build_const_int_vec(gallivm, type, 16);
c128 = lp_build_const_int_vec(gallivm, type, 128);
c255 = lp_build_const_int_vec(gallivm, type, 255);
cy = lp_build_const_int_vec(gallivm, type, 298);
cug = lp_build_const_int_vec(gallivm, type, -100);
cub = lp_build_const_int_vec(gallivm, type, 516);
cvr = lp_build_const_int_vec(gallivm, type, 409);
cvg = lp_build_const_int_vec(gallivm, type, -208);
/*
* y -= 16;
* u -= 128;
* v -= 128;
*/
y = LLVMBuildSub(builder, y, c16, "");
u = LLVMBuildSub(builder, u, c128, "");
v = LLVMBuildSub(builder, v, c128, "");
/*
* r = 298 * _y + 409 * _v + 128;
* g = 298 * _y - 100 * _u - 208 * _v + 128;
* b = 298 * _y + 516 * _u + 128;
*/
y = LLVMBuildMul(builder, y, cy, "");
y = LLVMBuildAdd(builder, y, c128, "");
*r = LLVMBuildMul(builder, v, cvr, "");
*g = LLVMBuildAdd(builder,
LLVMBuildMul(builder, u, cug, ""),
LLVMBuildMul(builder, v, cvg, ""),
"");
*b = LLVMBuildMul(builder, u, cub, "");
*r = LLVMBuildAdd(builder, *r, y, "");
*g = LLVMBuildAdd(builder, *g, y, "");
*b = LLVMBuildAdd(builder, *b, y, "");
/*
* r >>= 8;
* g >>= 8;
* b >>= 8;
*/
*r = LLVMBuildAShr(builder, *r, c8, "r");
*g = LLVMBuildAShr(builder, *g, c8, "g");
*b = LLVMBuildAShr(builder, *b, c8, "b");
/*
* Clamp
*/
*r = lp_build_clamp(&bld, *r, c0, c255);
*g = lp_build_clamp(&bld, *g, c0, c255);
*b = lp_build_clamp(&bld, *b, c0, c255);
}
/**
* Generic type conversion.
*
* TODO: Take a precision argument, or even better, add a new precision member
* to the lp_type union.
*/
void
lp_build_conv(struct gallivm_state *gallivm,
struct lp_type src_type,
struct lp_type dst_type,
const LLVMValueRef *src, unsigned num_srcs,
LLVMValueRef *dst, unsigned num_dsts)
{
LLVMBuilderRef builder = gallivm->builder;
struct lp_type tmp_type;
LLVMValueRef tmp[LP_MAX_VECTOR_LENGTH];
unsigned num_tmps;
unsigned i;
/* We must not loose or gain channels. Only precision */
assert(src_type.length * num_srcs == dst_type.length * num_dsts);
assert(src_type.length <= LP_MAX_VECTOR_LENGTH);
assert(dst_type.length <= LP_MAX_VECTOR_LENGTH);
assert(num_srcs <= LP_MAX_VECTOR_LENGTH);
assert(num_dsts <= LP_MAX_VECTOR_LENGTH);
tmp_type = src_type;
for(i = 0; i < num_srcs; ++i) {
assert(lp_check_value(src_type, src[i]));
tmp[i] = src[i];
}
num_tmps = num_srcs;
/* Special case 4x4f --> 1x16ub
*/
if (src_type.floating == 1 &&
src_type.fixed == 0 &&
src_type.sign == 1 &&
src_type.norm == 0 &&
src_type.width == 32 &&
src_type.length == 4 &&
dst_type.floating == 0 &&
dst_type.fixed == 0 &&
dst_type.sign == 0 &&
dst_type.norm == 1 &&
dst_type.width == 8 &&
dst_type.length == 16 &&
4 * num_dsts == num_srcs &&
util_cpu_caps.has_sse2)
{
struct lp_build_context bld;
struct lp_type int16_type = dst_type;
struct lp_type int32_type = dst_type;
LLVMValueRef const_255f;
unsigned i, j;
lp_build_context_init(&bld, gallivm, src_type);
int16_type.width *= 2;
int16_type.length /= 2;
int16_type.sign = 1;
int32_type.width *= 4;
int32_type.length /= 4;
int32_type.sign = 1;
const_255f = lp_build_const_vec(gallivm, src_type, 255.0f);
for (i = 0; i < num_dsts; ++i, src += 4) {
LLVMValueRef lo, hi;
for (j = 0; j < 4; ++j) {
tmp[j] = LLVMBuildFMul(builder, src[j], const_255f, "");
tmp[j] = lp_build_iround(&bld, tmp[j]);
}
/* relying on clamping behavior of sse2 intrinsics here */
lo = lp_build_pack2(gallivm, int32_type, int16_type, tmp[0], tmp[1]);
hi = lp_build_pack2(gallivm, int32_type, int16_type, tmp[2], tmp[3]);
dst[i] = lp_build_pack2(gallivm, int16_type, dst_type, lo, hi);
}
return;
}
/* Special case 2x8f --> 1x16ub
*/
else if (src_type.floating == 1 &&
src_type.fixed == 0 &&
src_type.sign == 1 &&
src_type.norm == 0 &&
src_type.width == 32 &&
src_type.length == 8 &&
dst_type.floating == 0 &&
dst_type.fixed == 0 &&
dst_type.sign == 0 &&
dst_type.norm == 1 &&
dst_type.width == 8 &&
dst_type.length == 16 &&
2 * num_dsts == num_srcs &&
util_cpu_caps.has_avx) {
struct lp_build_context bld;
struct lp_type int16_type = dst_type;
struct lp_type int32_type = dst_type;
LLVMValueRef const_255f;
unsigned i;
lp_build_context_init(&bld, gallivm, src_type);
int16_type.width *= 2;
int16_type.length /= 2;
int16_type.sign = 1;
int32_type.width *= 4;
int32_type.length /= 4;
int32_type.sign = 1;
const_255f = lp_build_const_vec(gallivm, src_type, 255.0f);
for (i = 0; i < num_dsts; ++i, src += 2) {
LLVMValueRef lo, hi, a, b;
a = LLVMBuildFMul(builder, src[0], const_255f, "");
b = LLVMBuildFMul(builder, src[1], const_255f, "");
a = lp_build_iround(&bld, a);
b = lp_build_iround(&bld, b);
tmp[0] = lp_build_extract_range(gallivm, a, 0, 4);
tmp[1] = lp_build_extract_range(gallivm, a, 4, 4);
tmp[2] = lp_build_extract_range(gallivm, b, 0, 4);
tmp[3] = lp_build_extract_range(gallivm, b, 4, 4);
/* relying on clamping behavior of sse2 intrinsics here */
lo = lp_build_pack2(gallivm, int32_type, int16_type, tmp[0], tmp[1]);
hi = lp_build_pack2(gallivm, int32_type, int16_type, tmp[2], tmp[3]);
dst[i] = lp_build_pack2(gallivm, int16_type, dst_type, lo, hi);
}
return;
}
/* Pre convert half-floats to floats
*/
else if (src_type.floating && src_type.width == 16)
{
for(i = 0; i < num_tmps; ++i)
tmp[i] = lp_build_half_to_float(gallivm, src_type, tmp[i]);
tmp_type.width = 32;
}
/*
* Clamp if necessary
*/
if(memcmp(&src_type, &dst_type, sizeof src_type) != 0) {
struct lp_build_context bld;
double src_min = lp_const_min(src_type);
double dst_min = lp_const_min(dst_type);
double src_max = lp_const_max(src_type);
double dst_max = lp_const_max(dst_type);
LLVMValueRef thres;
lp_build_context_init(&bld, gallivm, tmp_type);
if(src_min < dst_min) {
if(dst_min == 0.0)
thres = bld.zero;
else
thres = lp_build_const_vec(gallivm, src_type, dst_min);
for(i = 0; i < num_tmps; ++i)
tmp[i] = lp_build_max(&bld, tmp[i], thres);
}
if(src_max > dst_max) {
if(dst_max == 1.0)
thres = bld.one;
else
thres = lp_build_const_vec(gallivm, src_type, dst_max);
for(i = 0; i < num_tmps; ++i)
tmp[i] = lp_build_min(&bld, tmp[i], thres);
}
}
/*
* Scale to the narrowest range
*/
if(dst_type.floating) {
/* Nothing to do */
}
else if(tmp_type.floating) {
if(!dst_type.fixed && !dst_type.sign && dst_type.norm) {
for(i = 0; i < num_tmps; ++i) {
tmp[i] = lp_build_clamped_float_to_unsigned_norm(gallivm,
tmp_type,
dst_type.width,
tmp[i]);
}
tmp_type.floating = FALSE;
}
else {
double dst_scale = lp_const_scale(dst_type);
LLVMTypeRef tmp_vec_type;
if (dst_scale != 1.0) {
LLVMValueRef scale = lp_build_const_vec(gallivm, tmp_type, dst_scale);
for(i = 0; i < num_tmps; ++i)
tmp[i] = LLVMBuildFMul(builder, tmp[i], scale, "");
}
/* Use an equally sized integer for intermediate computations */
tmp_type.floating = FALSE;
tmp_vec_type = lp_build_vec_type(gallivm, tmp_type);
for(i = 0; i < num_tmps; ++i) {
#if 0
if(dst_type.sign)
tmp[i] = LLVMBuildFPToSI(builder, tmp[i], tmp_vec_type, "");
else
tmp[i] = LLVMBuildFPToUI(builder, tmp[i], tmp_vec_type, "");
#else
/* FIXME: there is no SSE counterpart for LLVMBuildFPToUI */
tmp[i] = LLVMBuildFPToSI(builder, tmp[i], tmp_vec_type, "");
#endif
}
}
}
else {
unsigned src_shift = lp_const_shift(src_type);
unsigned dst_shift = lp_const_shift(dst_type);
unsigned src_offset = lp_const_offset(src_type);
unsigned dst_offset = lp_const_offset(dst_type);
/* Compensate for different offsets */
if (dst_offset > src_offset && src_type.width > dst_type.width) {
for (i = 0; i < num_tmps; ++i) {
LLVMValueRef shifted;
LLVMValueRef shift = lp_build_const_int_vec(gallivm, tmp_type, src_shift - 1);
if(src_type.sign)
shifted = LLVMBuildAShr(builder, tmp[i], shift, "");
else
shifted = LLVMBuildLShr(builder, tmp[i], shift, "");
tmp[i] = LLVMBuildSub(builder, tmp[i], shifted, "");
}
}
if(src_shift > dst_shift) {
LLVMValueRef shift = lp_build_const_int_vec(gallivm, tmp_type,
src_shift - dst_shift);
for(i = 0; i < num_tmps; ++i)
if(src_type.sign)
tmp[i] = LLVMBuildAShr(builder, tmp[i], shift, "");
else
tmp[i] = LLVMBuildLShr(builder, tmp[i], shift, "");
}
}
/*
* Truncate or expand bit width
*
* No data conversion should happen here, although the sign bits are
* crucial to avoid bad clamping.
*/
{
struct lp_type new_type;
new_type = tmp_type;
new_type.sign = dst_type.sign;
new_type.width = dst_type.width;
new_type.length = dst_type.length;
lp_build_resize(gallivm, tmp_type, new_type, tmp, num_srcs, tmp, num_dsts);
tmp_type = new_type;
num_tmps = num_dsts;
}
/*
* Scale to the widest range
*/
if(src_type.floating) {
/* Nothing to do */
}
else if(!src_type.floating && dst_type.floating) {
if(!src_type.fixed && !src_type.sign && src_type.norm) {
for(i = 0; i < num_tmps; ++i) {
tmp[i] = lp_build_unsigned_norm_to_float(gallivm,
src_type.width,
dst_type,
tmp[i]);
}
tmp_type.floating = TRUE;
}
else {
double src_scale = lp_const_scale(src_type);
LLVMTypeRef tmp_vec_type;
/* Use an equally sized integer for intermediate computations */
tmp_type.floating = TRUE;
tmp_type.sign = TRUE;
tmp_vec_type = lp_build_vec_type(gallivm, tmp_type);
for(i = 0; i < num_tmps; ++i) {
#if 0
if(dst_type.sign)
tmp[i] = LLVMBuildSIToFP(builder, tmp[i], tmp_vec_type, "");
else
tmp[i] = LLVMBuildUIToFP(builder, tmp[i], tmp_vec_type, "");
#else
/* FIXME: there is no SSE counterpart for LLVMBuildUIToFP */
tmp[i] = LLVMBuildSIToFP(builder, tmp[i], tmp_vec_type, "");
#endif
}
if (src_scale != 1.0) {
LLVMValueRef scale = lp_build_const_vec(gallivm, tmp_type, 1.0/src_scale);
for(i = 0; i < num_tmps; ++i)
tmp[i] = LLVMBuildFMul(builder, tmp[i], scale, "");
}
}
}
else {
unsigned src_shift = lp_const_shift(src_type);
unsigned dst_shift = lp_const_shift(dst_type);
unsigned src_offset = lp_const_offset(src_type);
unsigned dst_offset = lp_const_offset(dst_type);
if (src_shift < dst_shift) {
LLVMValueRef pre_shift[LP_MAX_VECTOR_LENGTH];
LLVMValueRef shift = lp_build_const_int_vec(gallivm, tmp_type, dst_shift - src_shift);
for (i = 0; i < num_tmps; ++i) {
pre_shift[i] = tmp[i];
tmp[i] = LLVMBuildShl(builder, tmp[i], shift, "");
}
/* Compensate for different offsets */
if (dst_offset > src_offset) {
for (i = 0; i < num_tmps; ++i) {
tmp[i] = LLVMBuildSub(builder, tmp[i], pre_shift[i], "");
}
}
}
}
for(i = 0; i < num_dsts; ++i) {
dst[i] = tmp[i];
assert(lp_check_value(dst_type, dst[i]));
}
}
/**
* Special case for converting clamped IEEE-754 floats to unsigned norms.
*
* The mathematical voodoo below may seem excessive but it is actually
* paramount we do it this way for several reasons. First, there is no single
* precision FP to unsigned integer conversion Intel SSE instruction. Second,
* secondly, even if there was, since the FP's mantissa takes only a fraction
* of register bits the typically scale and cast approach would require double
* precision for accurate results, and therefore half the throughput
*
* Although the result values can be scaled to an arbitrary bit width specified
* by dst_width, the actual result type will have the same width.
*
* Ex: src = { float, float, float, float }
* return { i32, i32, i32, i32 } where each value is in [0, 2^dst_width-1].
*/
LLVMValueRef
lp_build_clamped_float_to_unsigned_norm(struct gallivm_state *gallivm,
struct lp_type src_type,
unsigned dst_width,
LLVMValueRef src)
{
LLVMBuilderRef builder = gallivm->builder;
LLVMTypeRef int_vec_type = lp_build_int_vec_type(gallivm, src_type);
LLVMValueRef res;
unsigned mantissa;
assert(src_type.floating);
assert(dst_width <= src_type.width);
src_type.sign = FALSE;
mantissa = lp_mantissa(src_type);
if (dst_width <= mantissa) {
/*
* Apply magic coefficients that will make the desired result to appear
* in the lowest significant bits of the mantissa, with correct rounding.
*
* This only works if the destination width fits in the mantissa.
*/
unsigned long long ubound;
unsigned long long mask;
double scale;
double bias;
ubound = (1ULL << dst_width);
mask = ubound - 1;
scale = (double)mask/ubound;
bias = (double)(1ULL << (mantissa - dst_width));
res = LLVMBuildFMul(builder, src, lp_build_const_vec(gallivm, src_type, scale), "");
res = LLVMBuildFAdd(builder, res, lp_build_const_vec(gallivm, src_type, bias), "");
res = LLVMBuildBitCast(builder, res, int_vec_type, "");
res = LLVMBuildAnd(builder, res,
lp_build_const_int_vec(gallivm, src_type, mask), "");
}
else if (dst_width == (mantissa + 1)) {
/*
* The destination width matches exactly what can be represented in
* floating point (i.e., mantissa + 1 bits). So do a straight
* multiplication followed by casting. No further rounding is necessary.
*/
double scale;
scale = (double)((1ULL << dst_width) - 1);
res = LLVMBuildFMul(builder, src,
lp_build_const_vec(gallivm, src_type, scale), "");
res = LLVMBuildFPToSI(builder, res, int_vec_type, "");
}
else {
/*
* The destination exceeds what can be represented in the floating point.
* So multiply by the largest power two we get away with, and when
* subtract the most significant bit to rescale to normalized values.
*
* The largest power of two factor we can get away is
* (1 << (src_type.width - 1)), because we need to use signed . In theory it
* should be (1 << (src_type.width - 2)), but IEEE 754 rules states
* INT_MIN should be returned in FPToSI, which is the correct result for
* values near 1.0!
*
* This means we get (src_type.width - 1) correct bits for values near 0.0,
* and (mantissa + 1) correct bits for values near 1.0. Equally or more
* important, we also get exact results for 0.0 and 1.0.
*/
unsigned n = MIN2(src_type.width - 1, dst_width);
double scale = (double)(1ULL << n);
unsigned lshift = dst_width - n;
unsigned rshift = n;
LLVMValueRef lshifted;
LLVMValueRef rshifted;
res = LLVMBuildFMul(builder, src,
lp_build_const_vec(gallivm, src_type, scale), "");
res = LLVMBuildFPToSI(builder, res, int_vec_type, "");
/*
* Align the most significant bit to its final place.
*
* This will cause 1.0 to overflow to 0, but the later adjustment will
* get it right.
*/
if (lshift) {
lshifted = LLVMBuildShl(builder, res,
lp_build_const_int_vec(gallivm, src_type,
lshift), "");
} else {
lshifted = res;
}
/*
* Align the most significant bit to the right.
*/
rshifted = LLVMBuildLShr(builder, res,
lp_build_const_int_vec(gallivm, src_type, rshift),
"");
/*
* Subtract the MSB to the LSB, therefore re-scaling from
* (1 << dst_width) to ((1 << dst_width) - 1).
*/
res = LLVMBuildSub(builder, lshifted, rshifted, "");
}
return res;
}
/*
* gen_operator_expression
*
* Code generation for operator expressions. Most of them have straightforward
* translations into LLVM instructions and are handled directly here.
*/
static LLVMValueRef
gen_operator_expression (gencodectx_t gctx, expr_node_t *exp, LLVMTypeRef neededtype)
{
expr_node_t *lhs = expr_op_lhs(exp);
expr_node_t *rhs = expr_op_rhs(exp);
optype_t op = expr_op_type(exp);
LLVMBuilderRef builder = gctx->curfn->builder;
LLVMTypeRef inttype;
LLVMValueRef lval, rval, result;
if (op == OPER_FETCH) {
return gen_fetch(gctx, rhs, neededtype);
}
if (op == OPER_ASSIGN) {
LLVMValueRef val = llvmgen_assignment(gctx, lhs, rhs);
return llvmgen_adjustval(gctx, val, neededtype, 0);
}
if (op == OPER_SHIFT) {
return gen_shift(gctx, lhs, rhs, neededtype);
}
inttype = LLVMIntTypeInContext(gctx->llvmctx, machine_scalar_bits(gctx->mach));
lval = (lhs == 0 ? 0 : llvmgen_expression(gctx, lhs, inttype));
rval = llvmgen_expression(gctx, rhs, inttype);
switch (op) {
case OPER_UNARY_PLUS:
result = rval;
break;
case OPER_UNARY_MINUS:
result = LLVMBuildNeg(builder, rval, llvmgen_temp(gctx));
break;
case OPER_ADD:
result = LLVMBuildAdd(builder, lval, rval, llvmgen_temp(gctx));
break;
case OPER_SUBTRACT:
result = LLVMBuildSub(builder, lval, rval, llvmgen_temp(gctx));
break;
case OPER_MULT:
result = LLVMBuildMul(builder, lval, rval, llvmgen_temp(gctx));
break;
case OPER_DIV:
result = LLVMBuildUDiv(builder, lval, rval, llvmgen_temp(gctx));
break;
case OPER_MODULO:
result = LLVMBuildURem(builder, lval, rval, llvmgen_temp(gctx));
break;
case OPER_AND:
result = LLVMBuildAnd(builder, lval, rval, llvmgen_temp(gctx));
break;
case OPER_OR:
result = LLVMBuildOr(builder, lval, rval, llvmgen_temp(gctx));
break;
case OPER_NOT:
result = LLVMBuildNot(builder, rval, llvmgen_temp(gctx));
break;
case OPER_XOR:
result = LLVMBuildXor(builder, lval, rval, llvmgen_temp(gctx));
break;
case OPER_EQV:
result = LLVMBuildXor(builder, lval, rval, llvmgen_temp(gctx));
result = LLVMBuildNot(builder, result, llvmgen_temp(gctx));
break;
default:
if (op >= OPER_CMP_EQL && op <= OPER_CMP_GEQA) {
result = LLVMBuildICmp(builder,
llvmgen_predfromop(op, machine_addr_signed(gctx->mach)),
lval, rval, llvmgen_temp(gctx));
} else {
// Everything should be covered
expr_signal(gctx->ectx, STC__INTCMPERR, "gen_operator_expression");
result = LLVMConstNull(inttype);
}
break;
}
return llvmgen_adjustval(gctx, result, neededtype, 0);
} /* gen_operator_expression */
/**
* See http://www.devmaster.net/forums/showthread.php?p=43580
*/
void
lp_build_log2_approx(struct lp_build_context *bld,
LLVMValueRef x,
LLVMValueRef *p_exp,
LLVMValueRef *p_floor_log2,
LLVMValueRef *p_log2)
{
const struct lp_type type = bld->type;
LLVMTypeRef vec_type = lp_build_vec_type(type);
LLVMTypeRef int_vec_type = lp_build_int_vec_type(type);
LLVMValueRef expmask = lp_build_int_const_scalar(type, 0x7f800000);
LLVMValueRef mantmask = lp_build_int_const_scalar(type, 0x007fffff);
LLVMValueRef one = LLVMConstBitCast(bld->one, int_vec_type);
LLVMValueRef i = NULL;
LLVMValueRef exp = NULL;
LLVMValueRef mant = NULL;
LLVMValueRef logexp = NULL;
LLVMValueRef logmant = NULL;
LLVMValueRef res = NULL;
if(p_exp || p_floor_log2 || p_log2) {
/* TODO: optimize the constant case */
if(LLVMIsConstant(x))
debug_printf("%s: inefficient/imprecise constant arithmetic\n",
__FUNCTION__);
assert(type.floating && type.width == 32);
i = LLVMBuildBitCast(bld->builder, x, int_vec_type, "");
/* exp = (float) exponent(x) */
exp = LLVMBuildAnd(bld->builder, i, expmask, "");
}
if(p_floor_log2 || p_log2) {
logexp = LLVMBuildLShr(bld->builder, exp, lp_build_int_const_scalar(type, 23), "");
logexp = LLVMBuildSub(bld->builder, logexp, lp_build_int_const_scalar(type, 127), "");
logexp = LLVMBuildSIToFP(bld->builder, logexp, vec_type, "");
}
if(p_log2) {
/* mant = (float) mantissa(x) */
mant = LLVMBuildAnd(bld->builder, i, mantmask, "");
mant = LLVMBuildOr(bld->builder, mant, one, "");
mant = LLVMBuildBitCast(bld->builder, mant, vec_type, "");
logmant = lp_build_polynomial(bld, mant, lp_build_log2_polynomial,
Elements(lp_build_log2_polynomial));
/* This effectively increases the polynomial degree by one, but ensures that log2(1) == 0*/
logmant = LLVMBuildMul(bld->builder, logmant, LLVMBuildSub(bld->builder, mant, bld->one, ""), "");
res = LLVMBuildAdd(bld->builder, logmant, logexp, "");
}
if(p_exp)
*p_exp = exp;
if(p_floor_log2)
*p_floor_log2 = logexp;
if(p_log2)
*p_log2 = res;
}