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x64: Lower shuffle and swizzle in ISLE (#4772)

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Lower `shuffle` and `swizzle` in ISLE.

This PR surfaced a bug with the lowering of `shuffle` when avx512vl and avx512vbmi are enabled: we use `vpermi2b` as the implementation, but panic if the immediate shuffle mask contains any out-of-bounds values. The behavior when the avx512 extensions are not present is that out-of-bounds values are turned into `0` in the result.

I've resolved this by detecting when the shuffle immediate has out-of-bounds indices in the avx512-enabled lowering, and generating an additional mask to zero out the lanes where those indices occur. This brings the avx512 case into line with the semantics of the `shuffle` op: 94bcbe8446/cranelift/codegen/meta/src/shared/instructions.rs (L1495-L1498)
This commit is contained in:
Trevor Elliott
2022-08-24 14:49:51 -07:00
committed by GitHub
parent b4c25ef63e
commit b8b6f2781e
12 changed files with 295 additions and 190 deletions
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12
cranelift/codegen/src/isa/x64/inst/emit_tests.rs
View File

@@ -66,6 +66,18 @@ impl Inst {
dst_hi: WritableGpr::from_reg(Gpr::new(regs::rdx()).unwrap()),
}
}
fn xmm_rm_r_evex(op: Avx512Opcode, src1: RegMem, src2: Reg, dst: Writable<Reg>) -> Self {
src1.assert_regclass_is(RegClass::Float);
debug_assert!(src2.class() == RegClass::Float);
debug_assert!(dst.to_reg().class() == RegClass::Float);
Inst::XmmRmREvex {
op,
src1: XmmMem::new(src1).unwrap(),
src2: Xmm::new(src2).unwrap(),
dst: WritableXmm::from_writable_reg(dst).unwrap(),
}
}
}
#[test]

17
cranelift/codegen/src/isa/x64/inst/mod.rs
View File

@@ -316,23 +316,6 @@ impl Inst {
}
}
pub(crate) fn xmm_rm_r_evex(
op: Avx512Opcode,
src1: RegMem,
src2: Reg,
dst: Writable<Reg>,
) -> Self {
src1.assert_regclass_is(RegClass::Float);
debug_assert!(src2.class() == RegClass::Float);
debug_assert!(dst.to_reg().class() == RegClass::Float);
Inst::XmmRmREvex {
op,
src1: XmmMem::new(src1).unwrap(),
src2: Xmm::new(src2).unwrap(),
dst: WritableXmm::from_writable_reg(dst).unwrap(),
}
}
pub(crate) fn xmm_uninit_value(dst: Writable<Reg>) -> Self {
debug_assert!(dst.to_reg().class() == RegClass::Float);
Inst::XmmUninitializedValue {