Struct Alternate

pub struct Alternate {
    pub feature: Feature,
    pub name: String,
}

An alternate version of an instruction.

Some AVX-specific context: some instructions have the same semantics in their SSE and AVX encodings. In these cases, we use this structure to record the name of the upgraded version of the instruction, allowing us to replace the SSE instruction with its AVX version during lowering. For AVX, using the VEX-encoded instruction is typically better than its legacy SSE version:

• VEX can encode three operands
• VEX allows unaligned memory access (avoids additional MOVUPS)
• VEX can compact byte-long prefixes into the VEX prefix
• VEX instructions zero the upper bits of XMM registers by default

Fields

feature: Feature

Indicate the feature check to use to trigger the replacement.

name: String

The full name (see Inst::name) of the instruction used for replacement.

Trait Implementations

impl Display for Alternate

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.