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vulkan: fix failing dequant shaders #15862

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vulkan: fix failing dequant shaders #15862

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14b4bca
vulkan: fix failing dequant shaders
jeffbolznv Sep 8, 2025
34f0e67
add missing const
jeffbolznv Sep 9, 2025
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2 changes: 1 addition & 1 deletion ggml/src/ggml-vulkan/vulkan-shaders/dequant_iq2_s.comp
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Expand Up @@ -29,7 +29,7 @@ void main() {
uint qs = data_a[ib].qs[4 * ib32 + l];
const uint8_t sign = data_a[ib].qs[QUANT_K / 8 + 4 * ib32 + l];
qs |= (qh << (8 - 2 * l)) & 0x300;
const uvec2 grid = iq2s_grid[qs & 511];
const uvec2 grid = iq2s_grid[qs];
const u8vec4 grid0 = unpack8(grid.x);
const u8vec4 grid1 = unpack8(grid.y);
data_b[b_idx + 8 * l + 0] = D_TYPE(db[l/2] * grid0.x * ((sign & 1) != 0 ? -1.0 : 1.0));
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3 changes: 2 additions & 1 deletion ggml/src/ggml-vulkan/vulkan-shaders/dequant_iq2_xxs.comp
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Expand Up @@ -33,7 +33,8 @@ void main() {
[[unroll]] for (uint l = 0; l < 4; ++l) {
const uint sign7 = bitfieldExtract(signscale, 7 * int(l), 7);
const uint sign8 = sign7 | (bitCount(sign7) << 7); // parity bit
const uvec2 grid = iq2xxs_grid[data_a[ib].qs[8 * is + l]];
const uint qs = data_a[ib].qs[8 * is + l];
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This, and iq3_xxs, were hitting KhronosGroup/glslang#3948

const uvec2 grid = iq2xxs_grid[qs];
const u8vec4 grid0 = unpack8(grid.x);
const u8vec4 grid1 = unpack8(grid.y);
data_b[b_idx + 8 * l + 0] = D_TYPE(db * grid0.x * ((sign8 & 1) != 0 ? -1.0 : 1.0));
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11 changes: 6 additions & 5 deletions ggml/src/ggml-vulkan/vulkan-shaders/dequant_iq3_s.comp
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Expand Up @@ -22,15 +22,16 @@ void main() {
const uint b_idx = 256 * ib + 32 * is;

const float d = float(data_a[ib].d);
const float db = d * (1 + 2 * ((data_a[ib].scales[is] >> (4 * (is % 2))) & 0xf));
const float db = d * (1 + 2 * ((data_a[ib].scales[is / 2] >> (4 * (is % 2))) & 0xf));

// We must produce 32 values using 4 sign bytes, 1 qh byte, 8 qs bytes.
uint qh = data_a[ib].qh[is];
[[unroll]] for (uint l = 0; l < 8; ++l) {
uint qs = data_a[ib].qs[8 * is + l];
uint gidx = qs | ((qh << (8 - l)) & 256);
uint8_t signs = data_a[ib].signs[8 * is + l / 2] >> (4 * (l & 1));
u8vec4 grid = unpack8(iq3s_grid[gidx]);
const uint iqs = 8 * is + l;
const uint qs = data_a[ib].qs[iqs];
const uint gidx = qs | ((qh << (8 - l)) & 256);
const uint8_t signs = data_a[ib].signs[iqs / 2] >> (4 * (l & 1));
const u8vec4 grid = unpack8(iq3s_grid[gidx]);
data_b[b_idx + 4 * l + 0] = D_TYPE(db * grid.x * ((signs & 1) != 0 ? -1.0 : 1.0));
data_b[b_idx + 4 * l + 1] = D_TYPE(db * grid.y * ((signs & 2) != 0 ? -1.0 : 1.0));
data_b[b_idx + 4 * l + 2] = D_TYPE(db * grid.z * ((signs & 4) != 0 ? -1.0 : 1.0));
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6 changes: 4 additions & 2 deletions ggml/src/ggml-vulkan/vulkan-shaders/dequant_iq3_xxs.comp
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Expand Up @@ -35,8 +35,10 @@ void main() {
const uint sign7 = bitfieldExtract(signscale, 7 * int(l), 7);
// Restore parity bit.
const uint sign8 = sign7 | (bitCount(sign7) << 7);
const u8vec4 grid0 = unpack8(iq3xxs_grid[data_a[ib].qs[8 * is + 2 * l]]);
const u8vec4 grid1 = unpack8(iq3xxs_grid[data_a[ib].qs[8 * is + 2 * l + 1]]);
const uint qs0 = data_a[ib].qs[8 * is + 2 * l];
const uint qs1 = data_a[ib].qs[8 * is + 2 * l + 1];
const u8vec4 grid0 = unpack8(iq3xxs_grid[qs0]);
const u8vec4 grid1 = unpack8(iq3xxs_grid[qs1]);
data_b[b_idx + 8 * l + 0] = D_TYPE(db * grid0.x * ((sign8 & 1) != 0 ? -1.0 : 1.0));
data_b[b_idx + 8 * l + 1] = D_TYPE(db * grid0.y * ((sign8 & 2) != 0 ? -1.0 : 1.0));
data_b[b_idx + 8 * l + 2] = D_TYPE(db * grid0.z * ((sign8 & 4) != 0 ? -1.0 : 1.0));
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