[release/9.0] Fix Issue #105820

[github-actions]

Backport of #106655 to release/9.0

/cc @TIHan @github-actions[bot]

Customer Impact

• Customer reported
• Found internally

Correctness issue with the HW intrinsic Bmi1.BitFieldExtract when used as part of a conditional. test eax eax was not being emitted before the jl instruction.

Regression

• Yes
• No

Testing

Fuzzlyn found the fix in its code generation. This was missed due to no stress testing against these APIs; Fuzzlyn generates code in a variety of scenarios that are not common to end-users. No tests were added as it appeared to be hit commonly when Fuzzlyn was generating code.

Risk

Low, the fix was straightforward and simple. Additional checks such as DoesWriteSignFlag(lastIns) && DoesWriteZeroFlag(lastIns) && DoesWriteParityFlag(lastIns) were used to help determine if the conditional flags were reset to zero or not.

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[carlossanlop]

@TIHan there's no main PR for this, the original PR was closed. I see my mistake. It was first backported to 9.0, then backported to RC1, and the 9.0 closed. Good.

Also, has this been approved by Tactics already? We're quite late in the process.

[JulieLeeMSFT]

I think his intention was to backport to RC2. I will talk to @TIHan to fix it.

@TIHan there's no main PR for this, the original PR was closed. I see my mistake. It was first backported to 9.0, then backported to RC1, and the 9.0 closed. Good.

Also, has this been approved by Tactics already? We're quite late in the process.

[carlossanlop]

Okay, apologies for the confusion. The title kept the [release/9.0-rc1] bit from the previous backport so it was confusing me. This PR is already targeting the release/9.0 branch, which is good (that's RC2).

[jeffschwMSFT]

approved. please get a code review. we can merge when ready.

[jeffschwMSFT]

@TIHan can you look at the failing CI and let me know when this is ready to merge?

[TIHan]

Yes, will do.

[TIHan]

Failures are unrelated to this change since all of them are arm related. There is a x86 installer build failure but is also unrelated.

So it can be merged.

[jeffschwMSFT]

/ba-g failures are unrelated to change