diff options
Diffstat (limited to '')
| -rw-r--r-- | compiler/rustc_codegen_cranelift/src/num.rs | 61 |
1 files changed, 42 insertions, 19 deletions
diff --git a/compiler/rustc_codegen_cranelift/src/num.rs b/compiler/rustc_codegen_cranelift/src/num.rs index 4ce8adb18..ecbab408d 100644 --- a/compiler/rustc_codegen_cranelift/src/num.rs +++ b/compiler/rustc_codegen_cranelift/src/num.rs @@ -150,18 +150,12 @@ pub(crate) fn codegen_int_binop<'tcx>( BinOp::BitXor => b.bxor(lhs, rhs), BinOp::BitAnd => b.band(lhs, rhs), BinOp::BitOr => b.bor(lhs, rhs), - BinOp::Shl => { - let lhs_ty = fx.bcx.func.dfg.value_type(lhs); - let actual_shift = fx.bcx.ins().band_imm(rhs, i64::from(lhs_ty.bits() - 1)); - fx.bcx.ins().ishl(lhs, actual_shift) - } + BinOp::Shl => b.ishl(lhs, rhs), BinOp::Shr => { - let lhs_ty = fx.bcx.func.dfg.value_type(lhs); - let actual_shift = fx.bcx.ins().band_imm(rhs, i64::from(lhs_ty.bits() - 1)); if signed { - fx.bcx.ins().sshr(lhs, actual_shift) + b.sshr(lhs, rhs) } else { - fx.bcx.ins().ushr(lhs, actual_shift) + b.ushr(lhs, rhs) } } // Compare binops handles by `codegen_binop`. @@ -279,22 +273,15 @@ pub(crate) fn codegen_checked_int_binop<'tcx>( } } BinOp::Shl => { - let lhs_ty = fx.bcx.func.dfg.value_type(lhs); - let masked_shift = fx.bcx.ins().band_imm(rhs, i64::from(lhs_ty.bits() - 1)); - let val = fx.bcx.ins().ishl(lhs, masked_shift); + let val = fx.bcx.ins().ishl(lhs, rhs); let ty = fx.bcx.func.dfg.value_type(val); let max_shift = i64::from(ty.bits()) - 1; let has_overflow = fx.bcx.ins().icmp_imm(IntCC::UnsignedGreaterThan, rhs, max_shift); (val, has_overflow) } BinOp::Shr => { - let lhs_ty = fx.bcx.func.dfg.value_type(lhs); - let masked_shift = fx.bcx.ins().band_imm(rhs, i64::from(lhs_ty.bits() - 1)); - let val = if !signed { - fx.bcx.ins().ushr(lhs, masked_shift) - } else { - fx.bcx.ins().sshr(lhs, masked_shift) - }; + let val = + if !signed { fx.bcx.ins().ushr(lhs, rhs) } else { fx.bcx.ins().sshr(lhs, rhs) }; let ty = fx.bcx.func.dfg.value_type(val); let max_shift = i64::from(ty.bits()) - 1; let has_overflow = fx.bcx.ins().icmp_imm(IntCC::UnsignedGreaterThan, rhs, max_shift); @@ -309,6 +296,42 @@ pub(crate) fn codegen_checked_int_binop<'tcx>( CValue::by_val_pair(res, has_overflow, out_layout) } +pub(crate) fn codegen_saturating_int_binop<'tcx>( + fx: &mut FunctionCx<'_, '_, 'tcx>, + bin_op: BinOp, + lhs: CValue<'tcx>, + rhs: CValue<'tcx>, +) -> CValue<'tcx> { + assert_eq!(lhs.layout().ty, rhs.layout().ty); + + let signed = type_sign(lhs.layout().ty); + let clif_ty = fx.clif_type(lhs.layout().ty).unwrap(); + let (min, max) = type_min_max_value(&mut fx.bcx, clif_ty, signed); + + let checked_res = crate::num::codegen_checked_int_binop(fx, bin_op, lhs, rhs); + let (val, has_overflow) = checked_res.load_scalar_pair(fx); + + let val = match (bin_op, signed) { + (BinOp::Add, false) => fx.bcx.ins().select(has_overflow, max, val), + (BinOp::Sub, false) => fx.bcx.ins().select(has_overflow, min, val), + (BinOp::Add, true) => { + let rhs = rhs.load_scalar(fx); + let rhs_ge_zero = fx.bcx.ins().icmp_imm(IntCC::SignedGreaterThanOrEqual, rhs, 0); + let sat_val = fx.bcx.ins().select(rhs_ge_zero, max, min); + fx.bcx.ins().select(has_overflow, sat_val, val) + } + (BinOp::Sub, true) => { + let rhs = rhs.load_scalar(fx); + let rhs_ge_zero = fx.bcx.ins().icmp_imm(IntCC::SignedGreaterThanOrEqual, rhs, 0); + let sat_val = fx.bcx.ins().select(rhs_ge_zero, min, max); + fx.bcx.ins().select(has_overflow, sat_val, val) + } + _ => unreachable!(), + }; + + CValue::by_val(val, lhs.layout()) +} + pub(crate) fn codegen_float_binop<'tcx>( fx: &mut FunctionCx<'_, '_, 'tcx>, bin_op: BinOp, |