fix ternary if (#250)

Use store and load to handle if expression as the blocks might be changed when generating sub-expressions.

Reviewed-on: M-Labs/nac3#250
Co-authored-by: ychenfo <yc@m-labs.hk>
Co-committed-by: ychenfo <yc@m-labs.hk>
This commit is contained in:
ychenfo 2022-03-29 06:54:00 +08:00 committed by sb10q
parent 94eebde4ea
commit 1f5826d352
2 changed files with 40 additions and 8 deletions

View File

@ -1226,21 +1226,44 @@ pub fn gen_expr<'ctx, 'a, G: CodeGenerator>(
.unwrap()
.to_basic_value_enum(ctx, generator)?
.into_int_value();
let body_ty = body.custom.unwrap();
let is_none = ctx.unifier.get_representative(body_ty) == ctx.primitives.none;
let result = if !is_none {
let llvm_ty = ctx.get_llvm_type(generator, body_ty);
Some(ctx.builder.build_alloca(llvm_ty, "if_exp_result"))
} else {
None
};
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 a = generator.gen_expr(ctx, body)?.unwrap().to_basic_value_enum(ctx, generator)?;
let a = generator.gen_expr(ctx, body)?;
match result {
None => None,
Some(v) => {
let a = a.unwrap().to_basic_value_enum(ctx, generator)?;
Some(ctx.builder.build_store(v, a))
}
};
ctx.builder.build_unconditional_branch(cont_bb);
ctx.builder.position_at_end(else_bb);
let b = generator.gen_expr(ctx, orelse)?.unwrap().to_basic_value_enum(ctx, generator)?;
let b = generator.gen_expr(ctx, orelse)?;
match result {
None => None,
Some(v) => {
let b = b.unwrap().to_basic_value_enum(ctx, generator)?;
Some(ctx.builder.build_store(v, b))
}
};
ctx.builder.build_unconditional_branch(cont_bb);
ctx.builder.position_at_end(cont_bb);
let phi = ctx.builder.build_phi(a.get_type(), "ifexpr");
phi.add_incoming(&[(&a, then_bb), (&b, else_bb)]);
phi.as_basic_value().into()
match result {
None => return Ok(None),
Some(v) => return Ok(Some(ctx.builder.build_load(v, "if_exp_val_load").into()))
}
}
ExprKind::Call { func, args, keywords } => {
let mut params = args

View File

@ -180,13 +180,22 @@ fn test_primitives() {
let expected = indoc! {"
; ModuleID = 'test'
source_filename = \"test\"
define i32 @testing(i32 %0, i32 %1) {
init:
%add = add i32 %0, %1
%cmp = icmp eq i32 %add, 1
%ifexpr = select i1 %cmp, i32 %0, i32 0
ret i32 %ifexpr
br i1 %cmp, label %then, label %else
then: ; preds = %init
br label %cont
else: ; preds = %init
br label %cont
cont: ; preds = %else, %then
%if_exp_result.0 = phi i32 [ %0, %then ], [ 0, %else ]
ret i32 %if_exp_result.0
}
"}
.trim();