/**************************************************************************
*
* Copyright 2009 VMware, Inc.
* All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sub license, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice (including the
* next paragraph) shall be included in all copies or substantial portions
* of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
* IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
* ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
**************************************************************************/
/**
* @file
* Helper functions for swizzling/shuffling.
*
* @author Jose Fonseca <jfonseca@vmware.com>
*/
#include <inttypes.h> /* for PRIx64 macro */
#include "util/u_debug.h"
#include "lp_bld_type.h"
#include "lp_bld_const.h"
#include "lp_bld_init.h"
#include "lp_bld_logic.h"
#include "lp_bld_swizzle.h"
#include "lp_bld_pack.h"
LLVMValueRef
lp_build_broadcast(struct gallivm_state *gallivm,
LLVMTypeRef vec_type,
LLVMValueRef scalar)
{
LLVMValueRef res;
if (LLVMGetTypeKind(vec_type) != LLVMVectorTypeKind) {
/* scalar */
assert(vec_type
== LLVMTypeOf
(scalar
)); res = scalar;
} else {
LLVMBuilderRef builder = gallivm->builder;
const unsigned length = LLVMGetVectorSize(vec_type);
LLVMValueRef undef = LLVMGetUndef(vec_type);
LLVMTypeRef i32_type = LLVMInt32TypeInContext(gallivm->context);
assert(LLVMGetElementType
(vec_type
) == LLVMTypeOf
(scalar
));
if (HAVE_LLVM >= 0x207) {
/* The shuffle vector is always made of int32 elements */
LLVMTypeRef i32_vec_type = LLVMVectorType(i32_type, length);
res = LLVMBuildInsertElement(builder, undef, scalar, LLVMConstNull(i32_type), "");
res = LLVMBuildShuffleVector(builder, res, undef, LLVMConstNull(i32_vec_type), "");
} else {
/* XXX: The above path provokes a bug in LLVM 2.6 */
unsigned i;
res = undef;
for(i = 0; i < length; ++i) {
LLVMValueRef index = lp_build_const_int32(gallivm, i);
res = LLVMBuildInsertElement(builder, res, scalar, index, "");
}
}
}
return res;
}
/**
* Broadcast
*/
LLVMValueRef
lp_build_broadcast_scalar(struct lp_build_context *bld,
LLVMValueRef scalar)
{
assert(lp_check_elem_type
(bld
->type
, LLVMTypeOf
(scalar
)));
return lp_build_broadcast(bld->gallivm, bld->vec_type, scalar);
}
/**
* Combined extract and broadcast (mere shuffle in most cases)
*/
LLVMValueRef
lp_build_extract_broadcast(struct gallivm_state *gallivm,
struct lp_type src_type,
struct lp_type dst_type,
LLVMValueRef vector,
LLVMValueRef index)
{
LLVMTypeRef i32t = LLVMInt32TypeInContext(gallivm->context);
LLVMValueRef res;
assert(src_type.
floating == dst_type.
floating); assert(src_type.
width == dst_type.
width);
assert(lp_check_value
(src_type
, vector
)); assert(LLVMTypeOf
(index
) == i32t
);
if (src_type.length == 1) {
if (dst_type.length == 1) {
/*
* Trivial scalar -> scalar.
*/
res = vector;
}
else {
/*
* Broadcast scalar -> vector.
*/
res = lp_build_broadcast(gallivm,
lp_build_vec_type(gallivm, dst_type),
vector);
}
}
else {
if (dst_type.length > 1) {
/*
* shuffle - result can be of different length.
*/
LLVMValueRef shuffle;
shuffle = lp_build_broadcast(gallivm,
LLVMVectorType(i32t, dst_type.length),
index);
res = LLVMBuildShuffleVector(gallivm->builder, vector,
LLVMGetUndef(lp_build_vec_type(gallivm, src_type)),
shuffle, "");
}
else {
/*
* Trivial extract scalar from vector.
*/
res = LLVMBuildExtractElement(gallivm->builder, vector, index, "");
}
}
return res;
}
/**
* Swizzle one channel into other channels.
*/
LLVMValueRef
lp_build_swizzle_scalar_aos(struct lp_build_context *bld,
LLVMValueRef a,
unsigned channel,
unsigned num_channels)
{
LLVMBuilderRef builder = bld->gallivm->builder;
const struct lp_type type = bld->type;
const unsigned n = type.length;
unsigned i, j;
if(a == bld->undef || a == bld->zero || a == bld->one || num_channels == 1)
return a;
assert(num_channels
== 2 || num_channels
== 4);
/* XXX: SSE3 has PSHUFB which should be better than bitmasks, but forcing
* using shuffles here actually causes worst results. More investigation is
* needed. */
if (type.width >= 16) {
/*
* Shuffle.
*/
LLVMTypeRef elem_type = LLVMInt32TypeInContext(bld->gallivm->context);
LLVMValueRef shuffles[LP_MAX_VECTOR_LENGTH];
for(j = 0; j < n; j += num_channels)
for(i = 0; i < num_channels; ++i)
shuffles[j + i] = LLVMConstInt(elem_type, j + channel, 0);
return LLVMBuildShuffleVector(builder, a, bld->undef, LLVMConstVector(shuffles, n), "");
}
else if (num_channels == 2) {
/*
* Bit mask and shifts
*
* XY XY .... XY <= input
* 0Y 0Y .... 0Y
* YY YY .... YY
* YY YY .... YY <= output
*/
struct lp_type type2;
LLVMValueRef tmp = NULL;
int shift;
a = LLVMBuildAnd(builder, a,
lp_build_const_mask_aos(bld->gallivm,
type, 1 << channel, num_channels), "");
type2 = type;
type2.floating = FALSE;
type2.width *= 2;
type2.length /= 2;
a = LLVMBuildBitCast(builder, a, lp_build_vec_type(bld->gallivm, type2), "");
/*
* Vector element 0 is always channel X.
*
* 76 54 32 10 (array numbering)
* Little endian reg in: YX YX YX YX
* Little endian reg out: YY YY YY YY if shift right (shift == -1)
* XX XX XX XX if shift left (shift == 1)
*
* 01 23 45 67 (array numbering)
* Big endian reg in: XY XY XY XY
* Big endian reg out: YY YY YY YY if shift left (shift == 1)
* XX XX XX XX if shift right (shift == -1)
*
*/
#ifdef PIPE_ARCH_LITTLE_ENDIAN
shift = channel == 0 ? 1 : -1;
#else
shift = channel == 0 ? -1 : 1;
#endif
if (shift > 0) {
tmp = LLVMBuildShl(builder, a, lp_build_const_int_vec(bld->gallivm, type2, shift * type.width), "");
} else if (shift < 0) {
tmp = LLVMBuildLShr(builder, a, lp_build_const_int_vec(bld->gallivm, type2, -shift * type.width), "");
}
if (tmp) {
a = LLVMBuildOr(builder, a, tmp, "");
}
return LLVMBuildBitCast(builder, a, lp_build_vec_type(bld->gallivm, type), "");
}
else {
/*
* Bit mask and recursive shifts
*
* Little-endian registers:
*
* 7654 3210
* WZYX WZYX .... WZYX <= input
* 00Y0 00Y0 .... 00Y0 <= mask
* 00YY 00YY .... 00YY <= shift right 1 (shift amount -1)
* YYYY YYYY .... YYYY <= shift left 2 (shift amount 2)
*
* Big-endian registers:
*
* 0123 4567
* XYZW XYZW .... XYZW <= input
* 0Y00 0Y00 .... 0Y00 <= mask
* YY00 YY00 .... YY00 <= shift left 1 (shift amount 1)
* YYYY YYYY .... YYYY <= shift right 2 (shift amount -2)
*
* shifts[] gives little-endian shift amounts; we need to negate for big-endian.
*/
struct lp_type type4;
const int shifts[4][2] = {
{ 1, 2},
{-1, 2},
{ 1, -2},
{-1, -2}
};
unsigned i;
a = LLVMBuildAnd(builder, a,
lp_build_const_mask_aos(bld->gallivm,
type, 1 << channel, 4), "");
/*
* Build a type where each element is an integer that cover the four
* channels.
*/
type4 = type;
type4.floating = FALSE;
type4.width *= 4;
type4.length /= 4;
a = LLVMBuildBitCast(builder, a, lp_build_vec_type(bld->gallivm, type4), "");
for(i = 0; i < 2; ++i) {
LLVMValueRef tmp = NULL;
int shift = shifts[channel][i];
/* See endianness diagram above */
#ifdef PIPE_ARCH_BIG_ENDIAN
shift = -shift;
#endif
if(shift > 0)
tmp = LLVMBuildShl(builder, a, lp_build_const_int_vec(bld->gallivm, type4, shift*type.width), "");
if(shift < 0)
tmp = LLVMBuildLShr(builder, a, lp_build_const_int_vec(bld->gallivm, type4, -shift*type.width), "");
if(tmp)
a = LLVMBuildOr(builder, a, tmp, "");
}
return LLVMBuildBitCast(builder, a, lp_build_vec_type(bld->gallivm, type), "");
}
}
/**
* Swizzle a vector consisting of an array of XYZW structs.
*
* This fills a vector of dst_len length with the swizzled channels from src.
*
* e.g. with swizzles = { 2, 1, 0 } and swizzle_count = 6 results in
* RGBA RGBA = BGR BGR BG
*
* @param swizzles the swizzle array
* @param num_swizzles the number of elements in swizzles
* @param dst_len the length of the result
*/
LLVMValueRef
lp_build_swizzle_aos_n(struct gallivm_state* gallivm,
LLVMValueRef src,
const unsigned char* swizzles,
unsigned num_swizzles,
unsigned dst_len)
{
LLVMBuilderRef builder = gallivm->builder;
LLVMValueRef shuffles[LP_MAX_VECTOR_WIDTH];
unsigned i;
assert(dst_len
< LP_MAX_VECTOR_WIDTH
);
for (i = 0; i < dst_len; ++i) {
int swizzle = swizzles[i % num_swizzles];
if (swizzle == LP_BLD_SWIZZLE_DONTCARE) {
shuffles[i] = LLVMGetUndef(LLVMInt32TypeInContext(gallivm->context));
} else {
shuffles[i] = lp_build_const_int32(gallivm, swizzle);
}
}
return LLVMBuildShuffleVector(builder, src, LLVMGetUndef(LLVMTypeOf(src)), LLVMConstVector(shuffles, dst_len), "");
}
LLVMValueRef
lp_build_swizzle_aos(struct lp_build_context *bld,
LLVMValueRef a,
const unsigned char swizzles[4])
{
LLVMBuilderRef builder = bld->gallivm->builder;
const struct lp_type type = bld->type;
const unsigned n = type.length;
unsigned i, j;
if (swizzles[0] == PIPE_SWIZZLE_RED &&
swizzles[1] == PIPE_SWIZZLE_GREEN &&
swizzles[2] == PIPE_SWIZZLE_BLUE &&
swizzles[3] == PIPE_SWIZZLE_ALPHA) {
return a;
}
if (swizzles[0] == swizzles[1] &&
swizzles[1] == swizzles[2] &&
swizzles[2] == swizzles[3]) {
switch (swizzles[0]) {
case PIPE_SWIZZLE_RED:
case PIPE_SWIZZLE_GREEN:
case PIPE_SWIZZLE_BLUE:
case PIPE_SWIZZLE_ALPHA:
return lp_build_swizzle_scalar_aos(bld, a, swizzles[0], 4);
case PIPE_SWIZZLE_ZERO:
return bld->zero;
case PIPE_SWIZZLE_ONE:
return bld->one;
case LP_BLD_SWIZZLE_DONTCARE:
return bld->undef;
default:
return bld->undef;
}
}
if (type.width >= 16) {
/*
* Shuffle.
*/
LLVMValueRef undef = LLVMGetUndef(lp_build_elem_type(bld->gallivm, type));
LLVMTypeRef i32t = LLVMInt32TypeInContext(bld->gallivm->context);
LLVMValueRef shuffles[LP_MAX_VECTOR_LENGTH];
LLVMValueRef aux[LP_MAX_VECTOR_LENGTH];
for(j = 0; j < n; j += 4) {
for(i = 0; i < 4; ++i) {
unsigned shuffle;
switch (swizzles[i]) {
default:
/* fall through */
case PIPE_SWIZZLE_RED:
case PIPE_SWIZZLE_GREEN:
case PIPE_SWIZZLE_BLUE:
case PIPE_SWIZZLE_ALPHA:
shuffle = j + swizzles[i];
shuffles[j + i] = LLVMConstInt(i32t, shuffle, 0);
break;
case PIPE_SWIZZLE_ZERO:
shuffle = type.length + 0;
shuffles[j + i] = LLVMConstInt(i32t, shuffle, 0);
if (!aux[0]) {
aux[0] = lp_build_const_elem(bld->gallivm, type, 0.0);
}
break;
case PIPE_SWIZZLE_ONE:
shuffle = type.length + 1;
shuffles[j + i] = LLVMConstInt(i32t, shuffle, 0);
if (!aux[1]) {
aux[1] = lp_build_const_elem(bld->gallivm, type, 1.0);
}
break;
case LP_BLD_SWIZZLE_DONTCARE:
shuffles[j + i] = LLVMGetUndef(i32t);
break;
}
}
}
for (i = 0; i < n; ++i) {
if (!aux[i]) {
aux[i] = undef;
}
}
return LLVMBuildShuffleVector(builder, a,
LLVMConstVector(aux, n),
LLVMConstVector(shuffles, n), "");
} else {
/*
* Bit mask and shifts.
*
* For example, this will convert BGRA to RGBA by doing
*
* Little endian:
* rgba = (bgra & 0x00ff0000) >> 16
* | (bgra & 0xff00ff00)
* | (bgra & 0x000000ff) << 16
*
* Big endian:A
* rgba = (bgra & 0x0000ff00) << 16
* | (bgra & 0x00ff00ff)
* | (bgra & 0xff000000) >> 16
*
* This is necessary not only for faster cause, but because X86 backend
* will refuse shuffles of <4 x i8> vectors
*/
LLVMValueRef res;
struct lp_type type4;
unsigned cond = 0;
unsigned chan;
int shift;
/*
* Start with a mixture of 1 and 0.
*/
for (chan = 0; chan < 4; ++chan) {
if (swizzles[chan] == PIPE_SWIZZLE_ONE) {
cond |= 1 << chan;
}
}
res = lp_build_select_aos(bld, cond, bld->one, bld->zero, 4);
/*
* Build a type where each element is an integer that cover the four
* channels.
*/
type4 = type;
type4.floating = FALSE;
type4.width *= 4;
type4.length /= 4;
a = LLVMBuildBitCast(builder, a, lp_build_vec_type(bld->gallivm, type4), "");
res = LLVMBuildBitCast(builder, res, lp_build_vec_type(bld->gallivm, type4), "");
/*
* Mask and shift the channels, trying to group as many channels in the
* same shift as possible. The shift amount is positive for shifts left
* and negative for shifts right.
*/
for (shift = -3; shift <= 3; ++shift) {
uint64_t mask = 0;
assert(type4.
width <= sizeof(mask
)*8);
/*
* Vector element numbers follow the XYZW order, so 0 is always X, etc.
* After widening 4 times we have:
*
* 3210
* Little-endian register layout: WZYX
*
* 0123
* Big-endian register layout: XYZW
*
* For little-endian, higher-numbered channels are obtained by a shift right
* (negative shift amount) and lower-numbered channels by a shift left
* (positive shift amount). The opposite is true for big-endian.
*/
for (chan = 0; chan < 4; ++chan) {
if (swizzles[chan] < 4) {
/* We need to move channel swizzles[chan] into channel chan */
#ifdef PIPE_ARCH_LITTLE_ENDIAN
if (swizzles[chan] - chan == -shift) {
mask |= ((1ULL << type.width) - 1) << (swizzles[chan] * type.width);
}
#else
if (swizzles[chan] - chan == shift) {
mask |= ((1ULL << type.width) - 1) << (type4.width - type.width) >> (swizzles[chan] * type.width);
}
#endif
}
}
if (mask) {
LLVMValueRef masked;
LLVMValueRef shifted;
if (0)
debug_printf("shift = %i, mask = %" PRIx64 "\n", shift, mask);
masked = LLVMBuildAnd(builder, a,
lp_build_const_int_vec(bld->gallivm, type4, mask), "");
if (shift > 0) {
shifted = LLVMBuildShl(builder, masked,
lp_build_const_int_vec(bld->gallivm, type4, shift*type.width), "");
} else if (shift < 0) {
shifted = LLVMBuildLShr(builder, masked,
lp_build_const_int_vec(bld->gallivm, type4, -shift*type.width), "");
} else {
shifted = masked;
}
res = LLVMBuildOr(builder, res, shifted, "");
}
}
return LLVMBuildBitCast(builder, res,
lp_build_vec_type(bld->gallivm, type), "");
}
}
/**
* Extended swizzle of a single channel of a SoA vector.
*
* @param bld building context
* @param unswizzled array with the 4 unswizzled values
* @param swizzle one of the PIPE_SWIZZLE_*
*
* @return the swizzled value.
*/
LLVMValueRef
lp_build_swizzle_soa_channel(struct lp_build_context *bld,
const LLVMValueRef *unswizzled,
unsigned swizzle)
{
switch (swizzle) {
case PIPE_SWIZZLE_RED:
case PIPE_SWIZZLE_GREEN:
case PIPE_SWIZZLE_BLUE:
case PIPE_SWIZZLE_ALPHA:
return unswizzled[swizzle];
case PIPE_SWIZZLE_ZERO:
return bld->zero;
case PIPE_SWIZZLE_ONE:
return bld->one;
default:
return bld->undef;
}
}
/**
* Extended swizzle of a SoA vector.
*
* @param bld building context
* @param unswizzled array with the 4 unswizzled values
* @param swizzles array of PIPE_SWIZZLE_*
* @param swizzled output swizzled values
*/
void
lp_build_swizzle_soa(struct lp_build_context *bld,
const LLVMValueRef *unswizzled,
const unsigned char swizzles[4],
LLVMValueRef *swizzled)
{
unsigned chan;
for (chan = 0; chan < 4; ++chan) {
swizzled[chan] = lp_build_swizzle_soa_channel(bld, unswizzled,
swizzles[chan]);
}
}
/**
* Do an extended swizzle of a SoA vector inplace.
*
* @param bld building context
* @param values intput/output array with the 4 values
* @param swizzles array of PIPE_SWIZZLE_*
*/
void
lp_build_swizzle_soa_inplace(struct lp_build_context *bld,
LLVMValueRef *values,
const unsigned char swizzles[4])
{
LLVMValueRef unswizzled[4];
unsigned chan;
for (chan = 0; chan < 4; ++chan) {
unswizzled[chan] = values[chan];
}
lp_build_swizzle_soa(bld, unswizzled, swizzles, values);
}
/**
* Transpose from AOS <-> SOA
*
* @param single_type_lp type of pixels
* @param src the 4 * n pixel input
* @param dst the 4 * n pixel output
*/
void
lp_build_transpose_aos(struct gallivm_state *gallivm,
struct lp_type single_type_lp,
const LLVMValueRef src[4],
LLVMValueRef dst[4])
{
struct lp_type double_type_lp = single_type_lp;
LLVMTypeRef single_type;
LLVMTypeRef double_type;
LLVMValueRef t0, t1, t2, t3;
double_type_lp.length >>= 1;
double_type_lp.width <<= 1;
double_type = lp_build_vec_type(gallivm, double_type_lp);
single_type = lp_build_vec_type(gallivm, single_type_lp);
/* Interleave x, y, z, w -> xy and zw */
t0 = lp_build_interleave2_half(gallivm, single_type_lp, src[0], src[1], 0);
t1 = lp_build_interleave2_half(gallivm, single_type_lp, src[2], src[3], 0);
t2 = lp_build_interleave2_half(gallivm, single_type_lp, src[0], src[1], 1);
t3 = lp_build_interleave2_half(gallivm, single_type_lp, src[2], src[3], 1);
/* Cast to double width type for second interleave */
t0 = LLVMBuildBitCast(gallivm->builder, t0, double_type, "t0");
t1 = LLVMBuildBitCast(gallivm->builder, t1, double_type, "t1");
t2 = LLVMBuildBitCast(gallivm->builder, t2, double_type, "t2");
t3 = LLVMBuildBitCast(gallivm->builder, t3, double_type, "t3");
/* Interleave xy, zw -> xyzw */
dst[0] = lp_build_interleave2_half(gallivm, double_type_lp, t0, t1, 0);
dst[1] = lp_build_interleave2_half(gallivm, double_type_lp, t0, t1, 1);
dst[2] = lp_build_interleave2_half(gallivm, double_type_lp, t2, t3, 0);
dst[3] = lp_build_interleave2_half(gallivm, double_type_lp, t2, t3, 1);
/* Cast back to original single width type */
dst[0] = LLVMBuildBitCast(gallivm->builder, dst[0], single_type, "dst0");
dst[1] = LLVMBuildBitCast(gallivm->builder, dst[1], single_type, "dst1");
dst[2] = LLVMBuildBitCast(gallivm->builder, dst[2], single_type, "dst2");
dst[3] = LLVMBuildBitCast(gallivm->builder, dst[3], single_type, "dst3");
}
/**
* Transpose from AOS <-> SOA for num_srcs
*/
void
lp_build_transpose_aos_n(struct gallivm_state *gallivm,
struct lp_type type,
const LLVMValueRef* src,
unsigned num_srcs,
LLVMValueRef* dst)
{
switch (num_srcs) {
case 1:
dst[0] = src[0];
break;
case 2:
{
/* Note: we must use a temporary incase src == dst */
LLVMValueRef lo, hi;
lo = lp_build_interleave2_half(gallivm, type, src[0], src[1], 0);
hi = lp_build_interleave2_half(gallivm, type, src[0], src[1], 1);
dst[0] = lo;
dst[1] = hi;
break;
}
case 4:
lp_build_transpose_aos(gallivm, type, src, dst);
break;
default:
};
}
/**
* Pack n-th element of aos values,
* pad out to destination size.
* i.e. x1 y1 _ _ x2 y2 _ _ will become x1 x2 _ _
*/
LLVMValueRef
lp_build_pack_aos_scalars(struct gallivm_state *gallivm,
struct lp_type src_type,
struct lp_type dst_type,
const LLVMValueRef src,
unsigned channel)
{
LLVMTypeRef i32t = LLVMInt32TypeInContext(gallivm->context);
LLVMValueRef undef = LLVMGetUndef(i32t);
LLVMValueRef shuffles[LP_MAX_VECTOR_LENGTH];
unsigned num_src = src_type.length / 4;
unsigned num_dst = dst_type.length;
unsigned i;
for (i = 0; i < num_src; i++) {
shuffles[i] = LLVMConstInt(i32t, i * 4 + channel, 0);
}
for (i = num_src; i < num_dst; i++) {
shuffles[i] = undef;
}
if (num_dst == 1) {
return LLVMBuildExtractElement(gallivm->builder, src, shuffles[0], "");
}
else {
return LLVMBuildShuffleVector(gallivm->builder, src, src,
LLVMConstVector(shuffles, num_dst), "");
}
}
/**
* Unpack and broadcast packed aos values consisting of only the
* first value, i.e. x1 x2 _ _ will become x1 x1 x1 x1 x2 x2 x2 x2
*/
LLVMValueRef
lp_build_unpack_broadcast_aos_scalars(struct gallivm_state *gallivm,
struct lp_type src_type,
struct lp_type dst_type,
const LLVMValueRef src)
{
LLVMTypeRef i32t = LLVMInt32TypeInContext(gallivm->context);
LLVMValueRef shuffles[LP_MAX_VECTOR_LENGTH];
unsigned num_dst = dst_type.length;
unsigned num_src = dst_type.length / 4;
unsigned i;
assert(num_dst
/ 4 <= src_type.
length);
for (i = 0; i < num_src; i++) {
shuffles[i*4] = LLVMConstInt(i32t, i, 0);
shuffles[i*4+1] = LLVMConstInt(i32t, i, 0);
shuffles[i*4+2] = LLVMConstInt(i32t, i, 0);
shuffles[i*4+3] = LLVMConstInt(i32t, i, 0);
}
if (num_src == 1) {
return lp_build_extract_broadcast(gallivm, src_type, dst_type,
src, shuffles[0]);
}
else {
return LLVMBuildShuffleVector(gallivm->builder, src, src,
LLVMConstVector(shuffles, num_dst), "");
}
}