mikros/rust
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Fix/count trailing zeroes (#95)

Browse Source 
* Fix count trailing zeroes
* Fix pop count
* Fix bit reverse
This commit is contained in:
antoyo 2021-09-27 20:35:45 -04:00 committed by GitHub
parent 63608ac6b3
commit 11c2023ef5
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 196 additions and 142 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
src/common.rs
View File

@ -302,6 +302,7 @@ pub trait SignType<'gcc, 'tcx> {
fn is_signed(&self, cx: &CodegenCx<'gcc, 'tcx>) -> bool;
fn is_unsigned(&self, cx: &CodegenCx<'gcc, 'tcx>) -> bool;
fn to_signed(&self, cx: &CodegenCx<'gcc, 'tcx>) -> Type<'gcc>;
fn to_unsigned(&self, cx: &CodegenCx<'gcc, 'tcx>) -> Type<'gcc>;
}
impl<'gcc, 'tcx> SignType<'gcc, 'tcx> for Type<'gcc> {
@ -333,6 +334,27 @@ impl<'gcc, 'tcx> SignType<'gcc, 'tcx> for Type<'gcc> {
self.clone()
}
}
fn to_unsigned(&self, cx: &CodegenCx<'gcc, 'tcx>) -> Type<'gcc> {
if self.is_i8(cx) {
cx.u8_type
}
else if self.is_i16(cx) {
cx.u16_type
}
else if self.is_i32(cx) {
cx.u32_type
}
else if self.is_i64(cx) {
cx.u64_type
}
else if self.is_i128(cx) {
cx.u128_type
}
else {
self.clone()
}
}
}
pub trait TypeReflection<'gcc, 'tcx> {

316
src/intrinsic/mod.rs
View File

@ -18,7 +18,7 @@ use rustc_target::spec::PanicStrategy;
use crate::abi::GccType;
use crate::builder::Builder;
use crate::common::TypeReflection;
use crate::common::{SignType, TypeReflection};
use crate::context::CodegenCx;
use crate::type_of::LayoutGccExt;
use crate::intrinsic::simd::generic_simd_intrinsic;
@ -520,163 +520,176 @@ fn int_type_width_signed<'gcc, 'tcx>(ty: Ty<'tcx>, cx: &CodegenCx<'gcc, 'tcx>) -
impl<'a, 'gcc, 'tcx> Builder<'a, 'gcc, 'tcx> {
fn bit_reverse(&mut self, width: u64, value: RValue<'gcc>) -> RValue<'gcc> {
let typ = value.get_type();
let result_type = value.get_type();
let typ = result_type.to_unsigned(self.cx);
let value =
if result_type.is_signed(self.cx) {
self.context.new_bitcast(None, value, typ)
}
else {
value
};
let context = &self.cx.context;
match width {
8 => {
// First step.
let left = self.and(value, context.new_rvalue_from_int(typ, 0xF0));
let left = self.lshr(left, context.new_rvalue_from_int(typ, 4));
let right = self.and(value, context.new_rvalue_from_int(typ, 0x0F));
let right = self.shl(right, context.new_rvalue_from_int(typ, 4));
let step1 = self.or(left, right);
let result =
match width {
8 => {
// First step.
let left = self.and(value, context.new_rvalue_from_int(typ, 0xF0));
let left = self.lshr(left, context.new_rvalue_from_int(typ, 4));
let right = self.and(value, context.new_rvalue_from_int(typ, 0x0F));
let right = self.shl(right, context.new_rvalue_from_int(typ, 4));
let step1 = self.or(left, right);
// Second step.
let left = self.and(step1, context.new_rvalue_from_int(typ, 0xCC));
let left = self.lshr(left, context.new_rvalue_from_int(typ, 2));
let right = self.and(step1, context.new_rvalue_from_int(typ, 0x33));
let right = self.shl(right, context.new_rvalue_from_int(typ, 2));
let step2 = self.or(left, right);
// Second step.
let left = self.and(step1, context.new_rvalue_from_int(typ, 0xCC));
let left = self.lshr(left, context.new_rvalue_from_int(typ, 2));
let right = self.and(step1, context.new_rvalue_from_int(typ, 0x33));
let right = self.shl(right, context.new_rvalue_from_int(typ, 2));
let step2 = self.or(left, right);
// Third step.
let left = self.and(step2, context.new_rvalue_from_int(typ, 0xAA));
let left = self.lshr(left, context.new_rvalue_from_int(typ, 1));
let right = self.and(step2, context.new_rvalue_from_int(typ, 0x55));
let right = self.shl(right, context.new_rvalue_from_int(typ, 1));
let step3 = self.or(left, right);
// Third step.
let left = self.and(step2, context.new_rvalue_from_int(typ, 0xAA));
let left = self.lshr(left, context.new_rvalue_from_int(typ, 1));
let right = self.and(step2, context.new_rvalue_from_int(typ, 0x55));
let right = self.shl(right, context.new_rvalue_from_int(typ, 1));
let step3 = self.or(left, right);
step3
},
16 => {
// First step.
let left = self.and(value, context.new_rvalue_from_int(typ, 0x5555));
let left = self.shl(left, context.new_rvalue_from_int(typ, 1));
let right = self.and(value, context.new_rvalue_from_int(typ, 0xAAAA));
let right = self.lshr(right, context.new_rvalue_from_int(typ, 1));
let step1 = self.or(left, right);
step3
},
16 => {
// First step.
let left = self.and(value, context.new_rvalue_from_int(typ, 0x5555));
let left = self.shl(left, context.new_rvalue_from_int(typ, 1));
let right = self.and(value, context.new_rvalue_from_int(typ, 0xAAAA));
let right = self.lshr(right, context.new_rvalue_from_int(typ, 1));
let step1 = self.or(left, right);
// Second step.
let left = self.and(step1, context.new_rvalue_from_int(typ, 0x3333));
let left = self.shl(left, context.new_rvalue_from_int(typ, 2));
let right = self.and(step1, context.new_rvalue_from_int(typ, 0xCCCC));
let right = self.lshr(right, context.new_rvalue_from_int(typ, 2));
let step2 = self.or(left, right);
// Second step.
let left = self.and(step1, context.new_rvalue_from_int(typ, 0x3333));
let left = self.shl(left, context.new_rvalue_from_int(typ, 2));
let right = self.and(step1, context.new_rvalue_from_int(typ, 0xCCCC));
let right = self.lshr(right, context.new_rvalue_from_int(typ, 2));
let step2 = self.or(left, right);
// Third step.
let left = self.and(step2, context.new_rvalue_from_int(typ, 0x0F0F));
let left = self.shl(left, context.new_rvalue_from_int(typ, 4));
let right = self.and(step2, context.new_rvalue_from_int(typ, 0xF0F0));
let right = self.lshr(right, context.new_rvalue_from_int(typ, 4));
let step3 = self.or(left, right);
// Third step.
let left = self.and(step2, context.new_rvalue_from_int(typ, 0x0F0F));
let left = self.shl(left, context.new_rvalue_from_int(typ, 4));
let right = self.and(step2, context.new_rvalue_from_int(typ, 0xF0F0));
let right = self.lshr(right, context.new_rvalue_from_int(typ, 4));
let step3 = self.or(left, right);
// Fourth step.
let left = self.and(step3, context.new_rvalue_from_int(typ, 0x00FF));
let left = self.shl(left, context.new_rvalue_from_int(typ, 8));
let right = self.and(step3, context.new_rvalue_from_int(typ, 0xFF00));
let right = self.lshr(right, context.new_rvalue_from_int(typ, 8));
let step4 = self.or(left, right);
// Fourth step.
let left = self.and(step3, context.new_rvalue_from_int(typ, 0x00FF));
let left = self.shl(left, context.new_rvalue_from_int(typ, 8));
let right = self.and(step3, context.new_rvalue_from_int(typ, 0xFF00));
let right = self.lshr(right, context.new_rvalue_from_int(typ, 8));
let step4 = self.or(left, right);
step4
},
32 => {
// TODO(antoyo): Refactor with other implementations.
// First step.
let left = self.and(value, context.new_rvalue_from_long(typ, 0x55555555));
let left = self.shl(left, context.new_rvalue_from_long(typ, 1));
let right = self.and(value, context.new_rvalue_from_long(typ, 0xAAAAAAAA));
let right = self.lshr(right, context.new_rvalue_from_long(typ, 1));
let step1 = self.or(left, right);
step4
},
32 => {
// TODO(antoyo): Refactor with other implementations.
// First step.
let left = self.and(value, context.new_rvalue_from_long(typ, 0x55555555));
let left = self.shl(left, context.new_rvalue_from_long(typ, 1));
let right = self.and(value, context.new_rvalue_from_long(typ, 0xAAAAAAAA));
let right = self.lshr(right, context.new_rvalue_from_long(typ, 1));
let step1 = self.or(left, right);
// Second step.
let left = self.and(step1, context.new_rvalue_from_long(typ, 0x33333333));
let left = self.shl(left, context.new_rvalue_from_long(typ, 2));
let right = self.and(step1, context.new_rvalue_from_long(typ, 0xCCCCCCCC));
let right = self.lshr(right, context.new_rvalue_from_long(typ, 2));
let step2 = self.or(left, right);
// Second step.
let left = self.and(step1, context.new_rvalue_from_long(typ, 0x33333333));
let left = self.shl(left, context.new_rvalue_from_long(typ, 2));
let right = self.and(step1, context.new_rvalue_from_long(typ, 0xCCCCCCCC));
let right = self.lshr(right, context.new_rvalue_from_long(typ, 2));
let step2 = self.or(left, right);
// Third step.
let left = self.and(step2, context.new_rvalue_from_long(typ, 0x0F0F0F0F));
let left = self.shl(left, context.new_rvalue_from_long(typ, 4));
let right = self.and(step2, context.new_rvalue_from_long(typ, 0xF0F0F0F0));
let right = self.lshr(right, context.new_rvalue_from_long(typ, 4));
let step3 = self.or(left, right);
// Third step.
let left = self.and(step2, context.new_rvalue_from_long(typ, 0x0F0F0F0F));
let left = self.shl(left, context.new_rvalue_from_long(typ, 4));
let right = self.and(step2, context.new_rvalue_from_long(typ, 0xF0F0F0F0));
let right = self.lshr(right, context.new_rvalue_from_long(typ, 4));
let step3 = self.or(left, right);
// Fourth step.
let left = self.and(step3, context.new_rvalue_from_long(typ, 0x00FF00FF));
let left = self.shl(left, context.new_rvalue_from_long(typ, 8));
let right = self.and(step3, context.new_rvalue_from_long(typ, 0xFF00FF00));
let right = self.lshr(right, context.new_rvalue_from_long(typ, 8));
let step4 = self.or(left, right);
// Fourth step.
let left = self.and(step3, context.new_rvalue_from_long(typ, 0x00FF00FF));
let left = self.shl(left, context.new_rvalue_from_long(typ, 8));
let right = self.and(step3, context.new_rvalue_from_long(typ, 0xFF00FF00));
let right = self.lshr(right, context.new_rvalue_from_long(typ, 8));
let step4 = self.or(left, right);
// Fifth step.
let left = self.and(step4, context.new_rvalue_from_long(typ, 0x0000FFFF));
let left = self.shl(left, context.new_rvalue_from_long(typ, 16));
let right = self.and(step4, context.new_rvalue_from_long(typ, 0xFFFF0000));
let right = self.lshr(right, context.new_rvalue_from_long(typ, 16));
let step5 = self.or(left, right);
// Fifth step.
let left = self.and(step4, context.new_rvalue_from_long(typ, 0x0000FFFF));
let left = self.shl(left, context.new_rvalue_from_long(typ, 16));
let right = self.and(step4, context.new_rvalue_from_long(typ, 0xFFFF0000));
let right = self.lshr(right, context.new_rvalue_from_long(typ, 16));
let step5 = self.or(left, right);
step5
},
64 => {
// First step.
let left = self.shl(value, context.new_rvalue_from_long(typ, 32));
let right = self.lshr(value, context.new_rvalue_from_long(typ, 32));
let step1 = self.or(left, right);
step5
},
64 => {
// First step.
let left = self.shl(value, context.new_rvalue_from_long(typ, 32));
let right = self.lshr(value, context.new_rvalue_from_long(typ, 32));
let step1 = self.or(left, right);
// Second step.
let left = self.and(step1, context.new_rvalue_from_long(typ, 0x0001FFFF0001FFFF));
let left = self.shl(left, context.new_rvalue_from_long(typ, 15));
let right = self.and(step1, context.new_rvalue_from_long(typ, 0xFFFE0000FFFE0000u64 as i64)); // TODO(antoyo): transmute the number instead?
let right = self.lshr(right, context.new_rvalue_from_long(typ, 17));
let step2 = self.or(left, right);
// Second step.
let left = self.and(step1, context.new_rvalue_from_long(typ, 0x0001FFFF0001FFFF));
let left = self.shl(left, context.new_rvalue_from_long(typ, 15));
let right = self.and(step1, context.new_rvalue_from_long(typ, 0xFFFE0000FFFE0000u64 as i64)); // TODO(antoyo): transmute the number instead?
let right = self.lshr(right, context.new_rvalue_from_long(typ, 17));
let step2 = self.or(left, right);
// Third step.
let left = self.lshr(step2, context.new_rvalue_from_long(typ, 10));
let left = self.xor(step2, left);
let temp = self.and(left, context.new_rvalue_from_long(typ, 0x003F801F003F801F));
// Third step.
let left = self.lshr(step2, context.new_rvalue_from_long(typ, 10));
let left = self.xor(step2, left);
let temp = self.and(left, context.new_rvalue_from_long(typ, 0x003F801F003F801F));
let left = self.shl(temp, context.new_rvalue_from_long(typ, 10));
let left = self.or(temp, left);
let step3 = self.xor(left, step2);
let left = self.shl(temp, context.new_rvalue_from_long(typ, 10));
let left = self.or(temp, left);
let step3 = self.xor(left, step2);
// Fourth step.
let left = self.lshr(step3, context.new_rvalue_from_long(typ, 4));
let left = self.xor(step3, left);
let temp = self.and(left, context.new_rvalue_from_long(typ, 0x0E0384210E038421));
// Fourth step.
let left = self.lshr(step3, context.new_rvalue_from_long(typ, 4));
let left = self.xor(step3, left);
let temp = self.and(left, context.new_rvalue_from_long(typ, 0x0E0384210E038421));
let left = self.shl(temp, context.new_rvalue_from_long(typ, 4));
let left = self.or(temp, left);
let step4 = self.xor(left, step3);
let left = self.shl(temp, context.new_rvalue_from_long(typ, 4));
let left = self.or(temp, left);
let step4 = self.xor(left, step3);
// Fifth step.
let left = self.lshr(step4, context.new_rvalue_from_long(typ, 2));
let left = self.xor(step4, left);
let temp = self.and(left, context.new_rvalue_from_long(typ, 0x2248884222488842));
// Fifth step.
let left = self.lshr(step4, context.new_rvalue_from_long(typ, 2));
let left = self.xor(step4, left);
let temp = self.and(left, context.new_rvalue_from_long(typ, 0x2248884222488842));
let left = self.shl(temp, context.new_rvalue_from_long(typ, 2));
let left = self.or(temp, left);
let step5 = self.xor(left, step4);
let left = self.shl(temp, context.new_rvalue_from_long(typ, 2));
let left = self.or(temp, left);
let step5 = self.xor(left, step4);
step5
},
128 => {
// TODO(antoyo): find a more efficient implementation?
let sixty_four = self.context.new_rvalue_from_long(typ, 64);
let high = self.context.new_cast(None, value >> sixty_four, self.u64_type);
let low = self.context.new_cast(None, value, self.u64_type);
step5
},
128 => {
// TODO(antoyo): find a more efficient implementation?
let sixty_four = self.context.new_rvalue_from_long(typ, 64);
let high = self.context.new_cast(None, value >> sixty_four, self.u64_type);
let low = self.context.new_cast(None, value, self.u64_type);
let reversed_high = self.bit_reverse(64, high);
let reversed_low = self.bit_reverse(64, low);
let reversed_high = self.bit_reverse(64, high);
let reversed_low = self.bit_reverse(64, low);
let new_low = self.context.new_cast(None, reversed_high, typ);
let new_high = self.context.new_cast(None, reversed_low, typ) << sixty_four;
let new_low = self.context.new_cast(None, reversed_high, typ);
let new_high = self.context.new_cast(None, reversed_low, typ) << sixty_four;
new_low | new_high
},
_ => {
panic!("cannot bit reverse with width = {}", width);
},
}
new_low | new_high
},
_ => {
panic!("cannot bit reverse with width = {}", width);
},
};
self.context.new_bitcast(None, result, result_type)
}
fn count_leading_zeroes(&self, width: u64, arg: RValue<'gcc>) -> RValue<'gcc> {
@ -746,6 +759,15 @@ impl<'a, 'gcc, 'tcx> Builder<'a, 'gcc, 'tcx> {
}
fn count_trailing_zeroes(&self, _width: u64, arg: RValue<'gcc>) -> RValue<'gcc> {
let result_type = arg.get_type();
let arg =
if result_type.is_signed(self.cx) {
let new_type = result_type.to_unsigned(self.cx);
self.context.new_bitcast(None, arg, new_type)
}
else {
arg
};
let arg_type = arg.get_type();
let (count_trailing_zeroes, expected_type) =
if arg_type.is_uchar(&self.cx) || arg_type.is_ushort(&self.cx) || arg_type.is_uint(&self.cx) {
@ -796,7 +818,7 @@ impl<'a, 'gcc, 'tcx> Builder<'a, 'gcc, 'tcx> {
let res = self.context.new_array_access(None, result, index);
return self.context.new_cast(None, res, arg_type);
return self.context.new_bitcast(None, res, result_type);
}
else {
unimplemented!("count_trailing_zeroes for {:?}", arg_type);
@ -810,7 +832,7 @@ impl<'a, 'gcc, 'tcx> Builder<'a, 'gcc, 'tcx> {
arg
};
let res = self.context.new_call(None, count_trailing_zeroes, &[arg]);
self.context.new_cast(None, res, arg_type)
self.context.new_bitcast(None, res, result_type)
}
fn int_width(&self, typ: Type<'gcc>) -> i64 {
@ -819,7 +841,16 @@ impl<'a, 'gcc, 'tcx> Builder<'a, 'gcc, 'tcx> {
fn pop_count(&self, value: RValue<'gcc>) -> RValue<'gcc> {
// TODO(antoyo): use the optimized version with fewer operations.
let value_type = value.get_type();
let result_type = value.get_type();
let value_type = result_type.to_unsigned(self.cx);
let value =
if result_type.is_signed(self.cx) {
self.context.new_bitcast(None, value, value_type)
}
else {
value
};
if value_type.is_u128(&self.cx) {
// TODO(antoyo): implement in the normal algorithm below to have a more efficient
@ -830,7 +861,8 @@ impl<'a, 'gcc, 'tcx> Builder<'a, 'gcc, 'tcx> {
let high = self.context.new_call(None, popcount, &[high]);
let low = self.context.new_cast(None, value, self.cx.ulonglong_type);
let low = self.context.new_call(None, popcount, &[low]);
return high + low;
let res = high + low;
return self.context.new_bitcast(None, res, result_type);
}
// First step.
@ -855,7 +887,7 @@ impl<'a, 'gcc, 'tcx> Builder<'a, 'gcc, 'tcx> {
let value = left + right;
if value_type.is_u8(&self.cx) {
return value;
return self.context.new_bitcast(None, value, result_type);
}
// Fourth step.
@ -866,7 +898,7 @@ impl<'a, 'gcc, 'tcx> Builder<'a, 'gcc, 'tcx> {
let value = left + right;
if value_type.is_u16(&self.cx) {
return value;
return self.context.new_bitcast(None, value, result_type);
}
// Fifth step.
@ -877,7 +909,7 @@ impl<'a, 'gcc, 'tcx> Builder<'a, 'gcc, 'tcx> {
let value = left + right;
if value_type.is_u32(&self.cx) {
return value;
return self.context.new_bitcast(None, value, result_type);
}
// Sixth step.
@ -887,7 +919,7 @@ impl<'a, 'gcc, 'tcx> Builder<'a, 'gcc, 'tcx> {
let right = shifted & mask;
let value = left + right;
value
self.context.new_bitcast(None, value, result_type)
}
// Algorithm from: https://blog.regehr.org/archives/1063