Repository navigation
SIMD splat causes compiler error #1409
Description
I've just been trying to upgrade my assemblyscript dependency from 0.9.4 to 0.14.3 and am now getting a not very informative compiler error for code which worked completely fine in the older version. After various back and fro, removing code in my project and slowly going back with trying older assemblyscript versions, I managed to narrow it down and replicate the issue first appearing in assemblyscript 0.10.0 and using this small test function:
export function foo(out: usize): usize {
const one = f32x4.splat(1);
v128.store(out, one);
return out;
}Btw. In the actual code base this issue arises in this function..
asc assembly/index.ts -b simd.wasm -t simd.wat --optimize --enable simd --runtime none --importMemory --memoryBase 0
Error [AssertionError]: assertion failed
at assert (<...>/node_modules/assemblyscript/dist/webpack:/assemblyscript/std/portable/index.js:193:9)
at m.compileVariableStatement (<...>/node_modules/assemblyscript/dist/webpack:/assemblyscript/src/compiler.ts:3093:17)
at m.compileStatement (<...>/node_modules/assemblyscript/dist/webpack:/assemblyscript/src/compiler.ts:2145:21)
at m.compileStatements (<...>/node_modules/assemblyscript/dist/webpack:/assemblyscript/src/compiler.ts:2193:23)
at m.compileFunctionBody (<...>/node_modules/assemblyscript/dist/webpack:/assemblyscript/src/compiler.ts:1502:20)
at m.compileFunction (<...>/node_modules/assemblyscript/dist/webpack:/assemblyscript/src/compiler.ts:1428:16)
at m.compileElement (<...>/node_modules/assemblyscript/dist/webpack:/assemblyscript/src/compiler.ts:878:38)
at m.compileExports (<...>/node_modules/assemblyscript/dist/webpack:/assemblyscript/src/compiler.ts:919:62)
at m.compileExports (<...>/node_modules/assemblyscript/dist/webpack:/assemblyscript/src/compiler.ts:927:14)
at m.compile (<...>/node_modules/assemblyscript/dist/webpack:/assemblyscript/src/compiler.ts:445:14)
<...>/node_modules/binaryen/index.js:57
function r(b){if(a.onAbort)a.onAbort(b);v(b);Aa=!0;throw new za("abort("+b+"). Build with -s ASSERTIONS=1 for more info.");}function Wa(b){var f=Xa;return String.prototype.startsWith?b.startsWith(f):0===b.indexOf(f)}var Xa="data:application/octet-stream;base64,",Ya="";if(!Wa(Ya)){var Za=Ya;Ya=a.locateFile?a.locateFile(Za,q):q+Za}var $a,ab;La.push({ga:function(){bb()}});var K={},cb=[];
^
Error: abort(AssertionError: assertion failed). Build with -s ASSERTIONS=1 for more info.
at process.r (<...>/node_modules/binaryen/index.js:57:58)
Activity
MaxGraey commentedon Jul 24, 2020
Could confirm. I guess it could be during
module.runExpression. cc @dcodeIOdcodeIO commentedon Jul 24, 2020
Problem appears to be that Binaryen can precompute the splat to a constant nowadays, but the code there really only expects an integer or a float to inline as a constant. A workaround would be to replace the
const onewith alet one.Regarding a proper fix, an important question is if it even makes sense to inline
v128s, i.e. instructions are almost always smaller than a constant and there might not even be a perf benefit between av128.constand av128.splat(really just guessing, not sure).MaxGraey commentedon Jul 24, 2020
v128.splat<i32>(1)will be definitely smaller51 bytesvs65 bytes(I calc whole module) for(v128.const i32x4 1 1 1 1). So I guess better skip pre-computation for splatpostspectacular commentedon Jul 25, 2020
Thank you both @dcodeIO & @MaxGraey for the quick fix and workaround to use
letinstead ofconst. Using v0.14.4 I can now successfully compile again, however getting a runtime error during module init mentioning a different function and SIMD opcode under Node 14.5.0 (seemingly forf32x4.abs, opcode:fd e0 01). Will do some more digging first and then might open another issue... sorry!MaxGraey commentedon Jul 25, 2020
It seems Node 14.5.0 still using old opcodes before renumbering: WebAssembly/simd#209
So it's not relate to AS. I could only suggest to use nightly version of node. Also try node 14.6.0
postspectacular commentedon Jul 25, 2020
Thanks @MaxGraey! Very much the case what @zeux mentioned in that linked issue:
build(simd): update asmscript dep