x64: Migrate XmmUnaryRmRImm{,Vex} to the new assembler
#10991
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This required definitions for `{v,}pshuf{lw,hw,d}` as well as reusing
existing definitions for `vround*` instructions. While no other changes
were needed in the assembler itself there was one minor ISLE change: the
`vrounds{s,d}` instructions have a register operand that is used to copy
to the upper bits of the result and this was not previously modeled in
ISLE. Instead during emission the destination had its upper bits
preserved, but this has proven to be problematic in the past where the
upper bits being carried from previous instructions can cause unintended
data dependencies and drastically slowing down tight loops. This commit
fills in this operand with `xmm_zero` which means the upper bits will
now be zeroed and any data dependencies from before will be severed.
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(Handing off review to @abrown if you don't mind -- I'm traveling this week at a conference) |
abrown
approved these changes
Jun 10, 2025
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This required definitions for
{v,}pshuf{lw,hw,d}as well as reusing existing definitions forvround*instructions. While no other changes were needed in the assembler itself there was one minor ISLE change: thevrounds{s,d}instructions have a register operand that is used to copy to the upper bits of the result and this was not previously modeled in ISLE. Instead during emission the destination had its upper bits preserved, but this has proven to be problematic in the past where the upper bits being carried from previous instructions can cause unintended data dependencies and drastically slowing down tight loops. This commit fills in this operand withxmm_zerowhich means the upper bits will now be zeroed and any data dependencies from before will be severed.