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Auto merge of #17942 - HKalbasi:fp-const-eval, r=HKalbasi
Implement floating point casts in const eval
fix #17926
| -rw-r--r-- | crates/hir-ty/src/consteval/tests.rs | 11 | ||||
| -rw-r--r-- | crates/hir-ty/src/mir/eval.rs | 94 |
2 files changed, 102 insertions, 3 deletions
diff --git a/crates/hir-ty/src/consteval/tests.rs b/crates/hir-ty/src/consteval/tests.rs index a0399a06f2..86228250c2 100644 --- a/crates/hir-ty/src/consteval/tests.rs +++ b/crates/hir-ty/src/consteval/tests.rs @@ -248,6 +248,17 @@ fn casts() { } #[test] +fn floating_point_casts() { + check_number(r#"const GOAL: usize = 12i32 as f32 as usize"#, 12); + check_number(r#"const GOAL: i8 = -12i32 as f64 as i8"#, -12); + check_number(r#"const GOAL: i32 = (-1ui8 as f32 + 2u64 as f32) as i32"#, 1); + check_number(r#"const GOAL: i8 = (0./0.) as i8"#, 0); + check_number(r#"const GOAL: i8 = (1./0.) as i8"#, 127); + check_number(r#"const GOAL: i8 = (-1./0.) as i8"#, -128); + check_number(r#"const GOAL: i64 = 1e18f64 as f32 as i64"#, 999999984306749440); +} + +#[test] fn raw_pointer_equality() { check_number( r#" diff --git a/crates/hir-ty/src/mir/eval.rs b/crates/hir-ty/src/mir/eval.rs index 590cb3952e..1bb0c18868 100644 --- a/crates/hir-ty/src/mir/eval.rs +++ b/crates/hir-ty/src/mir/eval.rs @@ -1518,9 +1518,97 @@ impl Evaluator<'_> { self.size_of_sized(target_ty, locals, "destination of int to int cast")?; Owned(current[0..dest_size].to_vec()) } - CastKind::FloatToInt => not_supported!("float to int cast"), - CastKind::FloatToFloat => not_supported!("float to float cast"), - CastKind::IntToFloat => not_supported!("float to int cast"), + CastKind::FloatToInt => { + let ty = self.operand_ty(operand, locals)?; + let TyKind::Scalar(chalk_ir::Scalar::Float(ty)) = ty.kind(Interner) else { + not_supported!("invalid float to int cast"); + }; + let value = self.eval_operand(operand, locals)?.get(self)?; + let value = match ty { + chalk_ir::FloatTy::F32 => { + let value = value.try_into().unwrap(); + f32::from_le_bytes(value) as f64 + } + chalk_ir::FloatTy::F64 => { + let value = value.try_into().unwrap(); + f64::from_le_bytes(value) + } + chalk_ir::FloatTy::F16 | chalk_ir::FloatTy::F128 => { + not_supported!("unstable floating point type f16 and f128"); + } + }; + let is_signed = matches!( + target_ty.kind(Interner), + TyKind::Scalar(chalk_ir::Scalar::Int(_)) + ); + let dest_size = + self.size_of_sized(target_ty, locals, "destination of float to int cast")?; + let dest_bits = dest_size * 8; + let (max, min) = if dest_bits == 128 { + (i128::MAX, i128::MIN) + } else if is_signed { + let max = 1i128 << (dest_bits - 1); + (max - 1, -max) + } else { + (1i128 << dest_bits, 0) + }; + let value = (value as i128).min(max).max(min); + let result = value.to_le_bytes(); + Owned(result[0..dest_size].to_vec()) + } + CastKind::FloatToFloat => { + let ty = self.operand_ty(operand, locals)?; + let TyKind::Scalar(chalk_ir::Scalar::Float(ty)) = ty.kind(Interner) else { + not_supported!("invalid float to int cast"); + }; + let value = self.eval_operand(operand, locals)?.get(self)?; + let value = match ty { + chalk_ir::FloatTy::F32 => { + let value = value.try_into().unwrap(); + f32::from_le_bytes(value) as f64 + } + chalk_ir::FloatTy::F64 => { + let value = value.try_into().unwrap(); + f64::from_le_bytes(value) + } + chalk_ir::FloatTy::F16 | chalk_ir::FloatTy::F128 => { + not_supported!("unstable floating point type f16 and f128"); + } + }; + let TyKind::Scalar(chalk_ir::Scalar::Float(target_ty)) = + target_ty.kind(Interner) + else { + not_supported!("invalid float to float cast"); + }; + match target_ty { + chalk_ir::FloatTy::F32 => Owned((value as f32).to_le_bytes().to_vec()), + chalk_ir::FloatTy::F64 => Owned((value as f64).to_le_bytes().to_vec()), + chalk_ir::FloatTy::F16 | chalk_ir::FloatTy::F128 => { + not_supported!("unstable floating point type f16 and f128"); + } + } + } + CastKind::IntToFloat => { + let current_ty = self.operand_ty(operand, locals)?; + let is_signed = matches!( + current_ty.kind(Interner), + TyKind::Scalar(chalk_ir::Scalar::Int(_)) + ); + let value = pad16(self.eval_operand(operand, locals)?.get(self)?, is_signed); + let value = i128::from_le_bytes(value); + let TyKind::Scalar(chalk_ir::Scalar::Float(target_ty)) = + target_ty.kind(Interner) + else { + not_supported!("invalid int to float cast"); + }; + match target_ty { + chalk_ir::FloatTy::F32 => Owned((value as f32).to_le_bytes().to_vec()), + chalk_ir::FloatTy::F64 => Owned((value as f64).to_le_bytes().to_vec()), + chalk_ir::FloatTy::F16 | chalk_ir::FloatTy::F128 => { + not_supported!("unstable floating point type f16 and f128"); + } + } + } CastKind::FnPtrToPtr => not_supported!("fn ptr to ptr cast"), }, }) |