forked from M-Labs/nac3
core: Simplify loop condition check for list comprehension
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parent
0205161e35
commit
50230e61f3
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@ -3,6 +3,7 @@ use std::{collections::HashMap, convert::TryInto, iter::once, iter::zip};
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use crate::{
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codegen::{
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concrete_type::{ConcreteFuncArg, ConcreteTypeEnum, ConcreteTypeStore},
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gen_in_range_check,
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get_llvm_type,
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get_llvm_abi_type,
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irrt::*,
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@ -963,11 +964,14 @@ pub fn gen_comprehension<'ctx, 'a, G: CodeGenerator>(
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let i = generator.gen_store_target(ctx, target, Some("i.addr"))?;
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ctx.builder.build_store(i, ctx.builder.build_int_sub(start, step, "start_init"));
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ctx.builder.build_unconditional_branch(test_bb);
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ctx.builder.build_conditional_branch(
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gen_in_range_check(ctx, start, stop, step),
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test_bb,
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cont_bb,
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);
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ctx.builder.position_at_end(test_bb);
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let sign =
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ctx.builder.build_int_compare(IntPredicate::SGT, step, zero_32, "sign");
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// add and test
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let tmp = ctx.builder.build_int_add(
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ctx.builder.build_load(i, "i").into_int_value(),
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@ -975,14 +979,8 @@ pub fn gen_comprehension<'ctx, 'a, G: CodeGenerator>(
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"start_loop",
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);
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ctx.builder.build_store(i, tmp);
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// if step > 0, continue when i < end
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let cmp1 = ctx.builder.build_int_compare(IntPredicate::SLT, tmp, stop, "cmp1");
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// if step < 0, continue when i > end
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let cmp2 = ctx.builder.build_int_compare(IntPredicate::SGT, tmp, stop, "cmp2");
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let pos = ctx.builder.build_and(sign, cmp1, "pos");
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let neg = ctx.builder.build_and(ctx.builder.build_not(sign, "inv"), cmp2, "neg");
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ctx.builder.build_conditional_branch(
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ctx.builder.build_or(pos, neg, "or"),
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gen_in_range_check(ctx, tmp, stop, step),
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body_bb,
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cont_bb,
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);
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@ -1001,7 +999,7 @@ pub fn gen_comprehension<'ctx, 'a, G: CodeGenerator>(
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ctx.build_gep_and_load(list, &[zero_size_t, zero_32], Some("list_content")).into_pointer_value();
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let counter = generator.gen_var_alloc(ctx, size_t.into(), Some("counter.addr"))?;
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// counter = -1
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ctx.builder.build_store(counter, size_t.const_int(u64::max_value(), true));
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ctx.builder.build_store(counter, size_t.const_int(u64::MAX, true));
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ctx.builder.build_unconditional_branch(test_bb);
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ctx.builder.position_at_end(test_bb);
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@ -899,3 +899,31 @@ fn bool_to_i8<'ctx>(
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),
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}
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}
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/// Generates a sequence of IR which checks whether `value` does not exceed the upper bound of the
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/// range as defined by `stop` and `step`.
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///
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/// Note that the generated IR will **not** check whether value is part of the range or whether
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/// value exceeds the lower bound of the range (as evident by the missing `start` argument).
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///
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/// The generated IR is equivalent to the following Rust code:
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///
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/// ```rust,ignore
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/// let sign = step > 0;
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/// let (lo, hi) = if sign { (value, stop) } else { (stop, value) };
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/// let cmp = lo < hi;
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/// ```
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///
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/// Returns an `i1` [IntValue] representing the result of whether the `value` is in the range.
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fn gen_in_range_check<'ctx, 'a>(
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ctx: &CodeGenContext<'ctx, 'a>,
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value: IntValue<'ctx>,
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stop: IntValue<'ctx>,
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step: IntValue<'ctx>,
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) -> IntValue<'ctx> {
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let sign = ctx.builder.build_int_compare(IntPredicate::SGT, step, ctx.ctx.i32_type().const_zero(), "");
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let lo = ctx.builder.build_select(sign, value, stop, "").into_int_value();
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let hi = ctx.builder.build_select(sign, stop, value, "").into_int_value();
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ctx.builder.build_int_compare(IntPredicate::SLT, lo, hi, "cmp")
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}
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@ -5,7 +5,10 @@ use super::{
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CodeGenContext, CodeGenerator,
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};
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use crate::{
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codegen::expr::gen_binop_expr,
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codegen::{
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expr::gen_binop_expr,
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gen_in_range_check,
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},
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toplevel::{DefinitionId, TopLevelDef},
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typecheck::typedef::{FunSignature, Type, TypeEnum},
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};
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@ -13,7 +16,7 @@ use inkwell::{
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attributes::{Attribute, AttributeLoc},
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basic_block::BasicBlock,
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types::BasicTypeEnum,
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values::{BasicValue, BasicValueEnum, FunctionValue, IntValue, PointerValue},
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values::{BasicValue, BasicValueEnum, FunctionValue, PointerValue},
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IntPredicate,
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};
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use nac3parser::ast::{
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@ -232,34 +235,6 @@ pub fn gen_assign<'ctx, 'a, G: CodeGenerator>(
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Ok(())
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}
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/// Generates a sequence of IR which checks whether `value` does not exceed the upper bound of the
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/// range as defined by `stop` and `step`.
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///
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/// Note that the generated IR will **not** check whether value is part of the range or whether
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/// value exceeds the lower bound of the range (as evident by the missing `start` argument).
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///
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/// The generated IR is equivalent to the following Rust code:
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///
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/// ```rust,ignore
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/// let sign = step > 0;
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/// let (lo, hi) = if sign { (value, stop) } else { (stop, value) };
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/// let cmp = lo < hi;
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/// ```
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///
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/// Returns an `i1` [IntValue] representing the result of whether the `value` is in the range.
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fn gen_in_range_check<'ctx, 'a>(
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ctx: &CodeGenContext<'ctx, 'a>,
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value: IntValue<'ctx>,
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stop: IntValue<'ctx>,
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step: IntValue<'ctx>,
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) -> IntValue<'ctx> {
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let sign = ctx.builder.build_int_compare(IntPredicate::SGT, step, ctx.ctx.i32_type().const_zero(), "");
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let lo = ctx.builder.build_select(sign, value, stop, "").into_int_value();
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let hi = ctx.builder.build_select(sign, stop, value, "").into_int_value();
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ctx.builder.build_int_compare(IntPredicate::SLT, lo, hi, "cmp")
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}
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/// See [CodeGenerator::gen_for].
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pub fn gen_for<'ctx, 'a, G: CodeGenerator>(
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generator: &mut G,
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