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nac3core: fix len on range with step of different sign #129

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sb10q merged 3 commits from len_range_fix into master 2021-12-13 10:44:33 +08:00
Conversation 4 Commits 3 Files Changed 3 +71 -35
1 changed files with 71 additions and 35 deletions
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Showing only changes of commit 1a9f39ee4a - Show all commits

106
nac3core/src/toplevel/builtins.rs
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@ -1,5 +1,5 @@
use std::cell::RefCell;
use inkwell::{IntPredicate, FloatPredicate, values::BasicValueEnum};
use inkwell::{IntPredicate, FloatPredicate, values::{BasicValueEnum, IntValue}};
use crate::{symbol_resolver::SymbolValue, codegen::expr::destructure_range};
use super::*;
@ -573,7 +573,7 @@ pub fn get_builtins(primitives: &mut (PrimitiveStore, Unifier)) -> BuiltinInfo {
ret: int32,
vars: vec![(list_var.1, list_var.0), (arg_ty.1, arg_ty.0)].into_iter().collect(),
}))),
var_id: Default::default(),
var_id: vec![arg_ty.1],
instance_to_symbol: Default::default(),
instance_to_stmt: Default::default(),
resolver: None,
@ -585,41 +585,9 @@ pub fn get_builtins(primitives: &mut (PrimitiveStore, Unifier)) -> BuiltinInfo {
let int32 = ctx.ctx.i32_type();
let zero = int32.const_zero();
if ctx.unifier.unioned(arg_ty, range_ty) {
let int1 = ctx.ctx.bool_type();
let one = int32.const_int(1, false);
let falze = int1.const_int(0, false);
let abs_intrinsic =
ctx.module.get_function("llvm.abs.i32").unwrap_or_else(|| {
let fn_type = int32.fn_type(&[int32.into(), int1.into()], false);
ctx.module.add_function("llvm.abs.i32", fn_type, None)
});
let arg = arg.into_pointer_value();
let (start, end, step) = destructure_range(ctx, arg);
let diff = ctx.builder.build_int_sub(end, start, "diff");
let diff = if let BasicValueEnum::IntValue(val) = ctx
.builder
.build_call(abs_intrinsic, &[diff.into(), falze.into()], "absdiff")
.try_as_basic_value()
.left()
.unwrap() {
val
} else {
unreachable!();
};
let diff = ctx.builder.build_int_sub(diff, one, "diff");
let step = if let BasicValueEnum::IntValue(val) = ctx
.builder
.build_call(abs_intrinsic, &[step.into(), falze.into()], "absstep")
.try_as_basic_value()
.left()
.unwrap() {
val
} else {
unreachable!();
};
let length = ctx.builder.build_int_signed_div(diff, step, "div");
let length = ctx.builder.build_int_add(length, int32.const_int(1, false), "add1");
Some(length.into())
Some(calculate_len_for_slice_range(ctx, start, end, step).into())
} else {
Some(ctx.build_gep_and_load(arg.into_pointer_value(), &[zero, zero]))
}
@ -648,4 +616,72 @@ pub fn get_builtins(primitives: &mut (PrimitiveStore, Unifier)) -> BuiltinInfo {
"len",
]
)
}
// equivalent code:
// def length(start, end, step != 0):
// diff = end - start
// # if diff == 0 OR `diff` and `step` are of different signs, always zero
// if diff * step <= 0:
// return 0
// else:
// return ((abs(diff) - 1) // abs(step)) + 1
pub fn calculate_len_for_slice_range<'ctx, 'a>(
ctx: &mut CodeGenContext<'ctx, 'a>,
start: IntValue<'ctx>,
end: IntValue<'ctx>,
step: IntValue<'ctx>,
) -> IntValue<'ctx> {
let int32 = ctx.ctx.i32_type();
let int1 = ctx.ctx.bool_type();
let falze = int1.const_int(0, false);
let abs_intrinsic =
ctx.module.get_function("llvm.abs.i32").unwrap_or_else(|| {
let fn_type = int32.fn_type(&[int32.into(), int1.into()], false);
ctx.module.add_function("llvm.abs.i32", fn_type, None)
});
let diff = ctx.builder.build_int_sub(end, start, "diff");
let test_mult = ctx.builder.build_int_mul(diff, step, "test_mult");
let test =
ctx.builder.build_int_compare(inkwell::IntPredicate::SLE, test_mult, int32.const_zero(), "cmp");
let current = ctx.builder.get_insert_block().unwrap().get_parent().unwrap();
let then_bb = ctx.ctx.append_basic_block(current, "then");
let else_bb = ctx.ctx.append_basic_block(current, "else");
let cont_bb = ctx.ctx.append_basic_block(current, "cont");
ctx.builder.build_conditional_branch(test, then_bb, else_bb);
ctx.builder.position_at_end(then_bb);
let length_zero = int32.const_zero();
ctx.builder.build_unconditional_branch(cont_bb);
ctx.builder.position_at_end(else_bb);
let diff = if let BasicValueEnum::IntValue(val) = ctx
.builder
.build_call(abs_intrinsic, &[diff.into(), falze.into()], "absdiff")
.try_as_basic_value()
.left()
.unwrap() {
val
} else {
unreachable!();
};
let diff = ctx.builder.build_int_sub(diff, int32.const_int(1, false), "diff");
let step = if let BasicValueEnum::IntValue(val) = ctx
.builder
.build_call(abs_intrinsic, &[step.into(), falze.into()], "absstep")
.try_as_basic_value()
.left()
.unwrap() {
val
} else {
unreachable!();
};
let length = ctx.builder.build_int_signed_div(diff, step, "div");
let length = ctx.builder.build_int_add(length, int32.const_int(1, false), "add1");
ctx.builder.build_unconditional_branch(cont_bb);
ctx.builder.position_at_end(cont_bb);
let phi = ctx.builder.build_phi(length_zero.get_type(), "lenphi");
phi.add_incoming(&[(&length_zero, then_bb), (&length, else_bb)]);
phi.as_basic_value().into_int_value()
}