wasm non-trapping float-to-int conversions #5014
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Note: Tested locally, but there are no tests attached to the PR yet. I will push tests to the PR later once I figure out how to port the spec tests. |
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For the tests, I think you can look at what I did for Sign extension. |
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| AnalysisAssert(!Saturate || doneLabel); |
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I feel we should assert here that dst is int32 or uint32 #Closed
lib/Backend/LowerMDShared.cpp
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| LoadFloatZero(zeroReg, instr); | ||
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| m_lowerer->InsertCompareBranch(src64, zeroReg, Js::OpCode::BrGt_A, tooBigLabel, instr, true /*no NaN check*/); | ||
| instr->InsertBefore(IR::BranchInstr::New(Js::OpCode::JP, nanLabel, m_func)); |
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if dst is unsigned, we could just jump to nanLabel since both branch just set dst to 0 #Closed
| @@ -314,6 +314,15 @@ MACRO_EXTEND_WMS( Conv_Check_FTUL , Long1Float1 , None | |||
| MACRO_EXTEND_WMS( Conv_Check_DTL , Long1Double1 , None ) | |||
| MACRO_EXTEND_WMS( Conv_Check_DTUL , Long1Double1 , None ) | |||
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| MACRO_EXTEND_WMS( Conv_Sat_DTI , Int1Double1 , None ) | |||
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This will require an update of the ByteCode Guid (you'll see unit test failure in ChakraFull) #Closed
| @@ -1260,6 +1260,13 @@ | |||
| <tags>exclude_dynapogo</tags> | |||
| </default> | |||
| </test> | |||
| <test> | |||
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In order to get this and not lose it next time I update the spec repo.
You have to add an entry in test\WasmSpec\convert-test-suite\config.json "folders": [ ... "features/nontrapping" ]
Then you need to run node convert-test-suite to generate rlexe.xml #Closed
lib/Backend/LowerMDShared.cpp
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| instr->InsertBefore(oobLabel); | ||
| if (Saturate) | ||
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| IR::LabelInstr * tooBigLabel = IR::LabelInstr::New(Js::OpCode::Label, m_func, true); |
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We can eliminate the additional cmp with zero by doing the following
xorps dst, dst ;; mov dst, 0
cmp minInt, src1
jae truncMinInt
jp done ;; src1 is NaN and we've initialized dst to 0, so we're done
cmp maxInt, src1
ja conversion ;; src1 is in the valid range do the conversion
mov dst, maxInt ;; we know we're greater then maxInt
jmp done
:truncMinInt
mov dst, minInt
jmp done
:conversion
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:doneWe can either initialize dst to 0 and do jp done or do jp nan; ... :nan mov dst, 0; jmp done;.
Merge pull request #5014 from MikeHolman:nontrapping Implements the wasm proposal, as specified here: https://github.com/WebAssembly/nontrapping-float-to-int-conversions Closes #3228
Implements the wasm proposal, as specified here:
https://github.com/WebAssembly/nontrapping-float-to-int-conversions
Closes #3228