@ -3,7 +3,7 @@
// ISLE integration glue.
pub ( super ) mod isle ;
use crate ::ir ::{ types , ExternalName , Inst as IRInst , InstructionData , LibCall , Opcode , Type } ;
use crate ::ir ::{ types , ExternalName , Inst as IRInst , LibCall , Opcode , Type } ;
use crate ::isa ::x64 ::abi ::* ;
use crate ::isa ::x64 ::inst ::args ::* ;
use crate ::isa ::x64 ::inst ::* ;
@ -160,100 +160,6 @@ fn input_to_imm(ctx: &mut Lower<Inst>, spec: InsnInput) -> Option<u64> {
. constant
}
/// Emit an instruction to insert a value `src` into a lane of `dst`.
fn emit_insert_lane ( ctx : & mut Lower < Inst > , src : RegMem , dst : Writable < Reg > , lane : u8 , ty : Type ) {
if ! ty . is_float ( ) {
let ( sse_op , size ) = match ty . lane_bits ( ) {
8 = > ( SseOpcode ::Pinsrb , OperandSize ::Size32 ) ,
16 = > ( SseOpcode ::Pinsrw , OperandSize ::Size32 ) ,
32 = > ( SseOpcode ::Pinsrd , OperandSize ::Size32 ) ,
64 = > ( SseOpcode ::Pinsrd , OperandSize ::Size64 ) ,
_ = > panic ! ( "Unable to insertlane for lane size: {}" , ty . lane_bits ( ) ) ,
} ;
ctx . emit ( Inst ::xmm_rm_r_imm ( sse_op , src , dst , lane , size ) ) ;
} else if ty = = types ::F32 {
let sse_op = SseOpcode ::Insertps ;
// Insert 32-bits from replacement (at index 00, bits 7:8) to vector (lane
// shifted into bits 5:6).
let lane = 0b00_00_00_00 | lane < < 4 ;
ctx . emit ( Inst ::xmm_rm_r_imm (
sse_op ,
src ,
dst ,
lane ,
OperandSize ::Size32 ,
) ) ;
} else if ty = = types ::F64 {
let sse_op = match lane {
// Move the lowest quadword in replacement to vector without changing
// the upper bits.
0 = > SseOpcode ::Movsd ,
// Move the low 64 bits of replacement vector to the high 64 bits of the
// vector.
1 = > SseOpcode ::Movlhps ,
_ = > unreachable ! ( ) ,
} ;
// Here we use the `xmm_rm_r` encoding because it correctly tells the register
// allocator how we are using `dst`: we are using `dst` as a `mod` whereas other
// encoding formats like `xmm_unary_rm_r` treat it as a `def`.
ctx . emit ( Inst ::xmm_rm_r ( sse_op , src , dst ) ) ;
} else {
panic ! ( "unable to emit insertlane for type: {}" , ty )
}
}
/// Emit an instruction to extract a lane of `src` into `dst`.
fn emit_extract_lane ( ctx : & mut Lower < Inst > , src : Reg , dst : Writable < Reg > , lane : u8 , ty : Type ) {
if ! ty . is_float ( ) {
let ( sse_op , size ) = match ty . lane_bits ( ) {
8 = > ( SseOpcode ::Pextrb , OperandSize ::Size32 ) ,
16 = > ( SseOpcode ::Pextrw , OperandSize ::Size32 ) ,
32 = > ( SseOpcode ::Pextrd , OperandSize ::Size32 ) ,
64 = > ( SseOpcode ::Pextrd , OperandSize ::Size64 ) ,
_ = > panic ! ( "Unable to extractlane for lane size: {}" , ty . lane_bits ( ) ) ,
} ;
let src = RegMem ::reg ( src ) ;
ctx . emit ( Inst ::xmm_rm_r_imm ( sse_op , src , dst , lane , size ) ) ;
} else if ty = = types ::F32 | | ty = = types ::F64 {
if lane = = 0 {
// Remove the extractlane instruction, leaving the float where it is. The upper
// bits will remain unchanged; for correctness, this relies on Cranelift type
// checking to avoid using those bits.
ctx . emit ( Inst ::gen_move ( dst , src , ty ) ) ;
} else {
// Otherwise, shuffle the bits in `lane` to the lowest lane.
let sse_op = SseOpcode ::Pshufd ;
let mask = match ty {
// Move the value at `lane` to lane 0, copying existing value at lane 0 to
// other lanes. Again, this relies on Cranelift type checking to avoid
// using those bits.
types ::F32 = > {
assert ! ( lane > 0 & & lane < 4 ) ;
0b00_00_00_00 | lane
}
// Move the value at `lane` 1 (we know it must be 1 because of the `if`
// statement above) to lane 0 and leave lane 1 unchanged. The Cranelift type
// checking assumption also applies here.
types ::F64 = > {
assert ! ( lane = = 1 ) ;
0b11_10_11_10
}
_ = > unreachable ! ( ) ,
} ;
let src = RegMem ::reg ( src ) ;
ctx . emit ( Inst ::xmm_rm_r_imm (
sse_op ,
src ,
dst ,
mask ,
OperandSize ::Size32 ,
) ) ;
}
} else {
panic ! ( "unable to emit extractlane for type: {}" , ty )
}
}
fn emit_vm_call (
ctx : & mut Lower < Inst > ,
flags : & Flags ,
@ -586,132 +492,15 @@ fn lower_insn_to_regs(
| Opcode ::RawBitcast
| Opcode ::Insertlane
| Opcode ::Shuffle
| Opcode ::Swizzle = > {
| Opcode ::Swizzle
| Opcode ::Extractlane
| Opcode ::ScalarToVector
| Opcode ::Splat = > {
implemented_in_isle ( ctx ) ;
}
Opcode ::DynamicStackAddr = > unimplemented ! ( "DynamicStackAddr" ) ,
Opcode ::Extractlane = > {
// The instruction format maps to variables like: %dst = extractlane %src, %lane
let ty = ty . unwrap ( ) ;
let dst = get_output_reg ( ctx , outputs [ 0 ] ) . only_reg ( ) . unwrap ( ) ;
let src_ty = ctx . input_ty ( insn , 0 ) ;
assert_eq ! ( src_ty . bits ( ) , 128 ) ;
let src = put_input_in_reg ( ctx , inputs [ 0 ] ) ;
let lane = if let InstructionData ::BinaryImm8 { imm , . . } = ctx . data ( insn ) {
* imm
} else {
unreachable ! ( ) ;
} ;
debug_assert ! ( lane < src_ty . lane_count ( ) as u8 ) ;
emit_extract_lane ( ctx , src , dst , lane , ty ) ;
}
Opcode ::ScalarToVector = > {
// When moving a scalar value to a vector register, we must be handle several
// situations:
// 1. a scalar float is already in an XMM register, so we simply move it
// 2. a scalar of any other type resides in a GPR register: MOVD moves the bits to an
// XMM register and zeroes the upper bits
// 3. a scalar (float or otherwise) that has previously been loaded from memory (e.g.
// the default lowering of Wasm's `load[32|64]_zero`) can be lowered to a single
// MOVSS/MOVSD instruction; to do this, we rely on `input_to_reg_mem` to sink the
// unused load.
let src = input_to_reg_mem ( ctx , inputs [ 0 ] ) ;
let src_ty = ctx . input_ty ( insn , 0 ) ;
let dst = get_output_reg ( ctx , outputs [ 0 ] ) . only_reg ( ) . unwrap ( ) ;
let dst_ty = ty . unwrap ( ) ;
assert ! ( src_ty = = dst_ty . lane_type ( ) & & dst_ty . bits ( ) = = 128 ) ;
match src {
RegMem ::Reg { reg } = > {
if src_ty . is_float ( ) {
// Case 1: when moving a scalar float, we simply move from one XMM register
// to another, expecting the register allocator to elide this. Here we
// assume that the upper bits of a scalar float have not been munged with
// (the same assumption the old backend makes).
ctx . emit ( Inst ::gen_move ( dst , reg , dst_ty ) ) ;
} else {
// Case 2: when moving a scalar value of any other type, use MOVD to zero
// the upper lanes.
let src_size = match src_ty . bits ( ) {
32 = > OperandSize ::Size32 ,
64 = > OperandSize ::Size64 ,
_ = > unimplemented ! ( "invalid source size for type: {}" , src_ty ) ,
} ;
ctx . emit ( Inst ::gpr_to_xmm ( SseOpcode ::Movd , src , src_size , dst ) ) ;
}
}
RegMem ::Mem { . . } = > {
// Case 3: when presented with `load + scalar_to_vector`, coalesce into a single
// MOVSS/MOVSD instruction.
let opcode = match src_ty . bits ( ) {
32 = > SseOpcode ::Movss ,
64 = > SseOpcode ::Movsd ,
_ = > unimplemented ! ( "unable to move scalar to vector for type: {}" , src_ty ) ,
} ;
ctx . emit ( Inst ::xmm_mov ( opcode , src , dst ) ) ;
}
}
}
Opcode ::Splat = > {
let ty = ty . unwrap ( ) ;
assert_eq ! ( ty . bits ( ) , 128 ) ;
let src_ty = ctx . input_ty ( insn , 0 ) ;
assert ! ( src_ty . bits ( ) < 128 ) ;
let src = input_to_reg_mem ( ctx , inputs [ 0 ] ) ;
let dst = get_output_reg ( ctx , outputs [ 0 ] ) . only_reg ( ) . unwrap ( ) ;
// We know that splat will overwrite all of the lanes of `dst` but it takes several
// instructions to do so. Because of the multiple instructions, there is no good way to
// declare `dst` a `def` except with the following pseudo-instruction.
ctx . emit ( Inst ::xmm_uninit_value ( dst ) ) ;
// TODO: eventually many of these sequences could be optimized with AVX's VBROADCAST*
// and VPBROADCAST*.
match ty . lane_bits ( ) {
8 = > {
emit_insert_lane ( ctx , src , dst , 0 , ty . lane_type ( ) ) ;
// Initialize a register with all 0s.
let tmp = ctx . alloc_tmp ( ty ) . only_reg ( ) . unwrap ( ) ;
ctx . emit ( Inst ::xmm_rm_r ( SseOpcode ::Pxor , RegMem ::from ( tmp ) , tmp ) ) ;
// Shuffle the lowest byte lane to all other lanes.
ctx . emit ( Inst ::xmm_rm_r ( SseOpcode ::Pshufb , RegMem ::from ( tmp ) , dst ) )
}
16 = > {
emit_insert_lane ( ctx , src . clone ( ) , dst , 0 , ty . lane_type ( ) ) ;
emit_insert_lane ( ctx , src , dst , 1 , ty . lane_type ( ) ) ;
// Shuffle the lowest two lanes to all other lanes.
ctx . emit ( Inst ::xmm_rm_r_imm (
SseOpcode ::Pshufd ,
RegMem ::from ( dst ) ,
dst ,
0 ,
OperandSize ::Size32 ,
) )
}
32 = > {
emit_insert_lane ( ctx , src , dst , 0 , ty . lane_type ( ) ) ;
// Shuffle the lowest lane to all other lanes.
ctx . emit ( Inst ::xmm_rm_r_imm (
SseOpcode ::Pshufd ,
RegMem ::from ( dst ) ,
dst ,
0 ,
OperandSize ::Size32 ,
) )
}
64 = > {
emit_insert_lane ( ctx , src . clone ( ) , dst , 0 , ty . lane_type ( ) ) ;
emit_insert_lane ( ctx , src , dst , 1 , ty . lane_type ( ) ) ;
}
_ = > panic ! ( "Invalid type to splat: {}" , ty ) ,
}
}
Opcode ::VanyTrue = > {
let dst = get_output_reg ( ctx , outputs [ 0 ] ) . only_reg ( ) . unwrap ( ) ;
let src_ty = ctx . input_ty ( insn , 0 ) ;
Trevor Elliott
2 years ago
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