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[AArch64] Use isKnownNonZero to optimize eligible compares to cmn and ccmn #96349

Merged
merged 2 commits into from
Jul 22, 2024
Merged

[AArch64] Use isKnownNonZero to optimize eligible compares to cmn and ccmn #96349

merged 2 commits into from
Jul 22, 2024

Commits on Jul 21, 2024

  1. Pre-commit tests (NFC)

    @AreaZR
    AreaZR committed Jul 21, 2024
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  2. [AArch64] Use isKnownNonZero to optimize eligible compares to cmn and… 

    … ccmn

The problematic case for unsigned comparisons occurs only when the second argument is zero, and in signed cases when the second argument is the minimum possible signed integer. If we can prove the register value be those, it is safe to fold into CMN and CCMN.

Source: https://devblogs.microsoft.com/oldnewthing/20210607-00/?p=105288
    @AreaZR
    AreaZR committed Jul 21, 2024
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