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Use raw_bitcast when legalizing splat

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raw_bitcast matches the intent of this legalization more clearly (to simply change the CLIF type without changing any bits) and the additional null encodings added are necessary for later instructions
This commit is contained in:
Andrew Brown
2019-08-21 15:15:27 -07:00
parent 8a6686ec45
commit ebc783e49b
3 changed files with 30 additions and 14 deletions
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37
cranelift/codegen/meta/src/isa/x86/encodings.rs
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@@ -234,7 +234,7 @@ impl PerCpuModeEncodings {
}
fn enc_both_isap(
&mut self,
inst: BoundInstruction,
inst: impl Clone + Into<InstSpec>,
template: Template,
isap: SettingPredicateNumber,
) {
@@ -243,7 +243,7 @@ impl PerCpuModeEncodings {
}
fn enc_both_instp(
&mut self,
inst: BoundInstruction,
inst: impl Clone + Into<InstSpec>,
template: Template,
instp: InstructionPredicateNode,
) {
@@ -1811,23 +1811,38 @@ pub(crate) fn define(
}
}
// SIMD bitcast f64 to all 8-bit-lane vectors (for legalizing splat.x8x16); assumes that f64 is stored in an XMM register
for ty in ValueType::all_lane_types().filter(|t| t.lane_bits() == 8) {
let instruction = bitcast.bind_vector_from_lane(ty, sse_vector_size).bind(F64);
// helper for generating null encodings for FPRs on both 32- and 64-bit architectures
let mut null_encode_32_64 = |instruction: BoundInstruction| {
e.enc32_rec(instruction.clone(), rec_null_fpr, 0);
e.enc64_rec(instruction, rec_null_fpr, 0);
}
};
// SIMD bitcast all 128-bit vectors to each other (for legalizing splat.x16x8)
for from_type in ValueType::all_lane_types().filter(allowed_simd_type) {
for to_type in
ValueType::all_lane_types().filter(|t| allowed_simd_type(t) && *t != from_type)
{
let instruction = raw_bitcast
.bind_vector_from_lane(to_type, sse_vector_size)
.bind_vector_from_lane(from_type, sse_vector_size);
e.enc32_rec(instruction.clone(), rec_null_fpr, 0);
e.enc64_rec(instruction, rec_null_fpr, 0);
null_encode_32_64(
raw_bitcast
.bind_vector_from_lane(to_type, sse_vector_size)
.bind_vector_from_lane(from_type, sse_vector_size),
);
}
}
// SIMD raw bitcast floats to vector (and back); assumes that floats are already stored in an XMM register
for float_type in &[F32, F64] {
for lane_type in ValueType::all_lane_types().filter(allowed_simd_type) {
null_encode_32_64(
raw_bitcast
.bind_vector_from_lane(lane_type, sse_vector_size)
.bind(*float_type),
);
null_encode_32_64(
raw_bitcast
.bind(*float_type)
.bind_vector_from_lane(lane_type, sse_vector_size),
);
}
}