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miri: reduce code duplication in SSE2 pmulh.w and pmulhu.w

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Not really a saving in terms of lines of code, but at least the logic is de-duplicated
This commit is contained in:
Eduardo Sánchez Muñoz 2023-09-13 21:58:28 +02:00
parent 8d590f2fa8
commit 9fbbfd2e39
1 changed files with 27 additions and 27 deletions
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54
src/tools/miri/src/shims/x86/sse2.rs
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@ -88,8 +88,8 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
this.write_immediate(res, &dest)?; this.write_immediate(res, &dest)?;
} }
} }
// Used to implement the _mm_mulhi_epi16 function. // Used to implement the _mm_mulhi_epi16 and _mm_mulhi_epu16 functions.
"pmulh.w" => { "pmulh.w" | "pmulhu.w" => {
let [left, right] = let [left, right] =
this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?; this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
@ -101,35 +101,35 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
assert_eq!(dest_len, right_len); assert_eq!(dest_len, right_len);
for i in 0..dest_len { for i in 0..dest_len {
let left = this.read_scalar(&this.project_index(&left, i)?)?.to_i16()?; let left = this.read_immediate(&this.project_index(&left, i)?)?;
let right = this.read_scalar(&this.project_index(&right, i)?)?.to_i16()?; let right = this.read_immediate(&this.project_index(&right, i)?)?;
let dest = this.project_index(&dest, i)?; let dest = this.project_index(&dest, i)?;
// Values are expanded from i16 to i32, so multiplication cannot overflow. // Widen the operands to avoid overflow
let res = i32::from(left).checked_mul(i32::from(right)).unwrap() >> 16; let twice_wide_ty = this.get_twice_wide_int_ty(left.layout.ty);
this.write_scalar(Scalar::from_i16(res.try_into().unwrap()), &dest)?; let twice_wide_layout = this.layout_of(twice_wide_ty)?;
} let left = this.int_to_int_or_float(&left, twice_wide_ty)?;
} let right = this.int_to_int_or_float(&right, twice_wide_ty)?;
// Used to implement the _mm_mulhi_epu16 function.
"pmulhu.w" => {
let [left, right] =
this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
let (left, left_len) = this.operand_to_simd(left)?; // Multiply
let (right, right_len) = this.operand_to_simd(right)?; let (multiplied, _overflow, _ty) = this.overflowing_binary_op(
let (dest, dest_len) = this.place_to_simd(dest)?; mir::BinOp::Mul,
&ImmTy::from_immediate(left, twice_wide_layout),
&ImmTy::from_immediate(right, twice_wide_layout),
)?;
// Keep the high half
let (high, _overflow, _ty) = this.overflowing_binary_op(
mir::BinOp::Shr,
&ImmTy::from_scalar(multiplied, twice_wide_layout),
&ImmTy::from_uint(dest.layout.size.bits(), twice_wide_layout),
)?;
assert_eq!(dest_len, left_len); // Narrow back to the original type
assert_eq!(dest_len, right_len); let res = this.int_to_int_or_float(
&ImmTy::from_scalar(high, twice_wide_layout),
for i in 0..dest_len { dest.layout.ty,
let left = this.read_scalar(&this.project_index(&left, i)?)?.to_u16()?; )?;
let right = this.read_scalar(&this.project_index(&right, i)?)?.to_u16()?; this.write_immediate(res, &dest)?;
let dest = this.project_index(&dest, i)?;
// Values are expanded from u16 to u32, so multiplication cannot overflow.
let res = u32::from(left).checked_mul(u32::from(right)).unwrap() >> 16;
this.write_scalar(Scalar::from_u16(res.try_into().unwrap()), &dest)?;
} }
} }
// Used to implement the _mm_mul_epu32 function. // Used to implement the _mm_mul_epu32 function.