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refactor(ivy): prevent `-0` from being generated (#34290) 

PR Close #34290
This commit is contained in:
Misko Hevery 2019-12-06 20:19:02 -08:00 committed by Andrew Kushnir
parent bb52fb798c
commit 4ef6f1ab2e
1 changed files with 4 additions and 1 deletions
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5
packages/core/src/render3/instructions/shared.ts
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@ -1216,7 +1216,10 @@ export function generateExpandoInstructionBlock(
tView.firstCreatePass, true,
'Expando block should only be generated on first create pass.');
const elementIndex = -(tNode.index - HEADER_OFFSET);
// Important: In JS `-x` and `0-x` is not the same! If `x===0` then `-x` will produce `-0` which
// requires non standard math arithmetic and it can prevent VM optimizations.
// `0-0` will always produce `0` and will not cause a potential deoptimization in VM.
const elementIndex = HEADER_OFFSET - tNode.index;
const providerStartIndex = tNode.providerIndexes & TNodeProviderIndexes.ProvidersStartIndexMask;
const providerCount = tView.data.length - providerStartIndex;
(tView.expandoInstructions || (tView.expandoInstructions = [