similar to: LLVM Matrix Multiplication Loop Vectorizer

<div> </div><div> </div><div>Hello,</div><div> </div><div>To me this is an issue in llvm loop vectorizer (if N is large enough to prevent complete unrolling of j-loop).</div><div> </div><div>Woud you mind to share stencil.ll than I would say more definitely what the issue

Does it happen due to loop carried dependence? if yes what is the solution to vectorize such codes? please reply. i m waiting. On Jul 1, 2017 12:30 PM, "hameeza ahmed" <hahmed2305 at gmail.com> wrote: > I even tried polly but still my llvm IR does not contain vector > instructions. i used the following command; > > clang -S -emit-llvm stencil.c -march=knl -O3

I am able to vectorize it with the following code; #include <stdio.h> #define N 100351 // This function computes 2D-5 point Jacobi stencil void stencil(int a[][N], int b[][N]) { int i, j, k; for (k = 0; k < N; k++) { for (i = 1; i <= N-2; i++) for (j = 1; j <= N-2; j++) b[i][j] = 0.25 * (a[i][j] + a[i-1][j] + a[i+1][j] + a[i][j-1] + a[i][j+1]); for

Your problem is due to GVN partial reduction elimination (PRE) which introduces a PHI node the current loop vectorizer cannot handle: opt -O3 stencil.ll -pass-remarks=loop-vectorize -pass-remarks-missed=loop-vectorize -pass-remarks-analysis=loop-vectorize remark: <unknown>:0:0: loop not vectorized: value that could not be identified as reduction is used outside the loop remark:

Hello, I am trying to vectorize following stencil code; #include <stdio.h> #define N 100351 // This function computes 2D-5 point Jacobi stencil void stencil(int a[restrict][N]) { int i, j, k; for (k = 0; k < 100; k++) { for (i = 1; i <= N-2; i++) { for (j = 1; j <= N-2; j++) { a[i][j] = 0.25 * (a[i][j] + a[i-1][j] + a[i+1][j] + a[i][j-1] +

Hello, My matrix multiplication code has variables allocated via double pointers on heap. The code is not getting vectorized. Following is the code. int **buffer_A = (int **)malloc(vecsize * sizeof(int *)); int **buffer_B = (int **)malloc(vecsize * sizeof(int *)); for(p = 0; p < vecsize; p++) { buffer_A[p] = (int *)malloc(vecsize * sizeof(int)); } for(p = 0; p < vecsize;

Thank You, It means vmovdqa64 zmm22, zmmword ptr [rip + .LCPI0_0] # zmm22 = [8,9,10,11,12,13,14,15] zmm22 will contain 64 bit constant values which are indexes here zmm22=8, 9, 10, 11, 12,13,14,15. not the values loaded from these locations. and zmm2 contains constant 4000. so, vpmuludq zmm14, zmm10, zmm2 ; will multiply the indexes values with 4000, as for array b the stride is 4000. zmm14=

I have matrix multiplication and stencil code. I vectorise it through the following command. opt -S -O3 -force-vector-width=2048 stencil.ll -o stencil_o3.ll in both the examples of matrix mult and stencil it vectorises fine when my loop iterations >2048. but if i keep both iterations and vector width=2048. it produces scalar code IR not vectorizes it. Is it llvm bug? Please help me.

i want to implement gather for v64i32. i wrote following code. def GATHER_256B : I<0x68, MRMSrcMem, (outs VR_2048:$dst), (ins i2048mem:$src), "GATHER_256B\t{$src, $dst|$dst, $src}", [(set VR_2048:$dst, (v64i32 (masked_gather addr:$src)))], IIC_MOV_MEM>, TA; def: Pat<(v64f32 (masked_gather addr:$src)), (GATHER_256B

Hello, I m trying to set vector width using #pragma clang loop vectorize_width(32) but i m getting width 8 for the following kernel; #define M 128 #define N 128 #define SQRT_FUN(x) sqrtf(x) int main(int argc, char** argv) { /* Variable declaration/allocation. */ double float_n = (double)N; double data[N*M]; double corr[M*M]; double mean[M]; double stddev[M]; uint32_t

Hello, I did as you said, Please tell me whether the following correct now?? def GATHER_256B : I<0x68, MRMSrcMem, (outs VR_2048:$dst, _.KRCWM:$mask_wb), (VR_2048:$src1, _.KRCWM:$mask, ins i2048mem:$src2), "GATHER_256B\t{$src2, {$dst}{${mask}}|${dst} {${mask}}, $src2}"), [(set VR_2048:$dst, _.KRCWM:$mask_wb, (v64i32 (GatherNode

Thank You. Still getting errors.I have modified my instructions as you said as follows: def GATHER_256B : I<0x68, MRMSrcMem, (outs VR_2048:$dst, VK64WM:$mask_wb), (ins VR_2048:$src1, VK64WM:$mask, i2048mem:$src2), "GATHER_256B\t{$src2, {$dst} {${mask}}|${dst} {${mask}}, $src2}", [(set VR_2048:$dst, VK64WM:$mask_wb, (v64i32 (masked_gather

Hello, I m unable to vectorize following kernel by opt tool; for (i = 0; i < _PB_NI; i++) for (j = 0; j < _PB_NJ; j++) { tmp[i][j] = 0; for (k = 0; k < _PB_NK; ++k) tmp[i][j] += alpha * A[i][k] * B[k][j]; } for (i = 0; i < _PB_NI; i++) for (j = 0; j < _PB_NL; j++) { D[i][j] *= beta; for (k = 0; k < _PB_NJ; ++k) D[i][j] +=

It would help if you sent the IR you're giving to opt or at least a complete C function and your clang command line. ~Craig On Wed, Mar 14, 2018 at 3:05 PM, hameeza ahmed <hahmed2305 at gmail.com> wrote: > Hello, > > I m unable to vectorize following kernel by opt tool; > > for (i = 0; i < _PB_NI; i++) > for (j = 0; j < _PB_NJ; j++) > { >

i removed printf from loop. Now getting no error. but the IR doesnot contain vectorized code. IR Output is as follows: ; ModuleID = 'sum-vec.ll' source_filename = "sum-vec.c" target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" target triple = "x86_64-unknown-linux-gnu" ; Function Attrs: norecurse nounwind readnone uwtable define i32 @main(i32, i8**

I assume compiler knows that your only have 2 input values that you just added together 1000 times. Despite the fact that you stored to a[i] and b[i] here, nothing reads them other than the addition in the same loop iteration. So the compiler easily removed the a and b arrays. Same with 'c', it's not read outside the loop so it doesn't need to exist. So the compiler turned your

even if i make my code as follows: vectorized instructions not get emitted. What to do? int main(int argc, char** argv) { int a[1000], b[1000], c[1000]; int g=0; int aa=atoi(argv[1]), bb=atoi(argv[2]); for (int i=0; i<1000; i++) { a[i]=aa, b[i]=bb; c[i]=a[i] + b[i]; g+=c[i]; } printf("sum: %d\n", g); return 0; } On Thu, Aug 17, 2017 at 10:03 PM, Craig Topper <craig.topper at

Hi everybody, I'm trying to pass a matrix from R to C, where some computation is done for performance reasons, and back to R for evaluation. But I've run into the problem that R and C seem to have different ways of representing the matrix in main memory. The C representation of a 2D matrix in linear memory is concatenation of the rows whereas in R, it's a concatenation of the

I want to vectorize the user given inputs. when opt does vectorization user supplied inputs (from a text file) will be added using AVX vector instructions. as you pointed; When i changed my code to following: int main(int argc, char** argv) { int a[1000], b[1000], c[1000]; int aa=atoi(argv[1]), bb=atoi(argv[2]); for (int i=0; i<1000; i++) { a[i]=aa, b[i]=bb; c[i]=a[i] + b[i];

lli sum-vec03.ll 5 2 #0 0x0000000000c1f818 (lli+0xc1f818) #1 0x0000000000c1d90e (lli+0xc1d90e) #2 0x0000000000c1da5c (lli+0xc1da5c) #3 0x00007f987c2c3d10 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x10d10) #4 0x00007f987c6f0038 #5 0x0000000000989f8c (lli+0x989f8c) #6 0x00000000009383dc (lli+0x9383dc) #7 0x000000000057eedd (lli+0x57eedd) #8 0x00007f987b464a40 __libc_start_main