diff --git a/clippy_lints/src/floating_point_arithmetic.rs b/clippy_lints/src/floating_point_arithmetic.rs index 4efd0689267..e3ee4296119 100644 --- a/clippy_lints/src/floating_point_arithmetic.rs +++ b/clippy_lints/src/floating_point_arithmetic.rs @@ -1,6 +1,6 @@ use crate::consts::{ constant, constant_simple, Constant, - Constant::{F32, F64}, + Constant::{Int, F32, F64}, }; use crate::utils::{higher, numeric_literal, span_lint_and_sugg, sugg, SpanlessEq}; use if_chain::if_chain; @@ -293,6 +293,30 @@ fn check_powf(cx: &LateContext<'_>, expr: &Expr<'_>, args: &[Expr<'_>]) { } } +fn check_powi(cx: &LateContext<'_, '_>, expr: &Expr<'_>, args: &[Expr<'_>]) { + // Check argument + if let Some((value, _)) = constant(cx, cx.tables, &args[1]) { + let (lint, help, suggestion) = match value { + Int(2) => ( + IMPRECISE_FLOPS, + "square can be computed more accurately", + format!("{} * {}", Sugg::hir(cx, &args[0], ".."), Sugg::hir(cx, &args[0], "..")), + ), + _ => return, + }; + + span_lint_and_sugg( + cx, + lint, + expr.span, + help, + "consider using", + suggestion, + Applicability::MachineApplicable, + ); + } +} + // TODO: Lint expressions of the form `x.exp() - y` where y > 1 // and suggest usage of `x.exp_m1() - (y - 1)` instead fn check_expm1(cx: &LateContext<'_>, expr: &Expr<'_>) { @@ -489,6 +513,7 @@ impl<'tcx> LateLintPass<'tcx> for FloatingPointArithmetic { "ln" => check_ln1p(cx, expr, args), "log" => check_log_base(cx, expr, args), "powf" => check_powf(cx, expr, args), + "powi" => check_powi(cx, expr, args), _ => {}, } } diff --git a/tests/ui/floating_point_log.fixed b/tests/ui/floating_point_log.fixed index 42c5e5d2bae..7dc7ee94aff 100644 --- a/tests/ui/floating_point_log.fixed +++ b/tests/ui/floating_point_log.fixed @@ -25,11 +25,11 @@ fn check_ln1p() { let _ = 2.0f32.ln_1p(); let _ = x.ln_1p(); let _ = (x / 2.0).ln_1p(); - let _ = x.powi(2).ln_1p(); - let _ = (x.powi(2) / 2.0).ln_1p(); + let _ = x.powi(3).ln_1p(); + let _ = (x.powi(3) / 2.0).ln_1p(); let _ = ((std::f32::consts::E - 1.0)).ln_1p(); let _ = x.ln_1p(); - let _ = x.powi(2).ln_1p(); + let _ = x.powi(3).ln_1p(); let _ = (x + 2.0).ln_1p(); let _ = (x / 2.0).ln_1p(); // Cases where the lint shouldn't be applied @@ -43,9 +43,9 @@ fn check_ln1p() { let _ = 2.0f64.ln_1p(); let _ = x.ln_1p(); let _ = (x / 2.0).ln_1p(); - let _ = x.powi(2).ln_1p(); + let _ = x.powi(3).ln_1p(); let _ = x.ln_1p(); - let _ = x.powi(2).ln_1p(); + let _ = x.powi(3).ln_1p(); let _ = (x + 2.0).ln_1p(); let _ = (x / 2.0).ln_1p(); // Cases where the lint shouldn't be applied diff --git a/tests/ui/floating_point_log.rs b/tests/ui/floating_point_log.rs index 8be0d9ad56f..01181484e7d 100644 --- a/tests/ui/floating_point_log.rs +++ b/tests/ui/floating_point_log.rs @@ -25,11 +25,11 @@ fn check_ln1p() { let _ = (1f32 + 2.0).ln(); let _ = (1.0 + x).ln(); let _ = (1.0 + x / 2.0).ln(); - let _ = (1.0 + x.powi(2)).ln(); - let _ = (1.0 + x.powi(2) / 2.0).ln(); + let _ = (1.0 + x.powi(3)).ln(); + let _ = (1.0 + x.powi(3) / 2.0).ln(); let _ = (1.0 + (std::f32::consts::E - 1.0)).ln(); let _ = (x + 1.0).ln(); - let _ = (x.powi(2) + 1.0).ln(); + let _ = (x.powi(3) + 1.0).ln(); let _ = (x + 2.0 + 1.0).ln(); let _ = (x / 2.0 + 1.0).ln(); // Cases where the lint shouldn't be applied @@ -43,9 +43,9 @@ fn check_ln1p() { let _ = (1f64 + 2.0).ln(); let _ = (1.0 + x).ln(); let _ = (1.0 + x / 2.0).ln(); - let _ = (1.0 + x.powi(2)).ln(); + let _ = (1.0 + x.powi(3)).ln(); let _ = (x + 1.0).ln(); - let _ = (x.powi(2) + 1.0).ln(); + let _ = (x.powi(3) + 1.0).ln(); let _ = (x + 2.0 + 1.0).ln(); let _ = (x / 2.0 + 1.0).ln(); // Cases where the lint shouldn't be applied diff --git a/tests/ui/floating_point_log.stderr b/tests/ui/floating_point_log.stderr index 943fbdb0b83..900dc2b7933 100644 --- a/tests/ui/floating_point_log.stderr +++ b/tests/ui/floating_point_log.stderr @@ -77,14 +77,14 @@ LL | let _ = (1.0 + x / 2.0).ln(); error: ln(1 + x) can be computed more accurately --> $DIR/floating_point_log.rs:28:13 | -LL | let _ = (1.0 + x.powi(2)).ln(); - | ^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `x.powi(2).ln_1p()` +LL | let _ = (1.0 + x.powi(3)).ln(); + | ^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `x.powi(3).ln_1p()` error: ln(1 + x) can be computed more accurately --> $DIR/floating_point_log.rs:29:13 | -LL | let _ = (1.0 + x.powi(2) / 2.0).ln(); - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `(x.powi(2) / 2.0).ln_1p()` +LL | let _ = (1.0 + x.powi(3) / 2.0).ln(); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `(x.powi(3) / 2.0).ln_1p()` error: ln(1 + x) can be computed more accurately --> $DIR/floating_point_log.rs:30:13 @@ -101,8 +101,8 @@ LL | let _ = (x + 1.0).ln(); error: ln(1 + x) can be computed more accurately --> $DIR/floating_point_log.rs:32:13 | -LL | let _ = (x.powi(2) + 1.0).ln(); - | ^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `x.powi(2).ln_1p()` +LL | let _ = (x.powi(3) + 1.0).ln(); + | ^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `x.powi(3).ln_1p()` error: ln(1 + x) can be computed more accurately --> $DIR/floating_point_log.rs:33:13 @@ -143,8 +143,8 @@ LL | let _ = (1.0 + x / 2.0).ln(); error: ln(1 + x) can be computed more accurately --> $DIR/floating_point_log.rs:46:13 | -LL | let _ = (1.0 + x.powi(2)).ln(); - | ^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `x.powi(2).ln_1p()` +LL | let _ = (1.0 + x.powi(3)).ln(); + | ^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `x.powi(3).ln_1p()` error: ln(1 + x) can be computed more accurately --> $DIR/floating_point_log.rs:47:13 @@ -155,8 +155,8 @@ LL | let _ = (x + 1.0).ln(); error: ln(1 + x) can be computed more accurately --> $DIR/floating_point_log.rs:48:13 | -LL | let _ = (x.powi(2) + 1.0).ln(); - | ^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `x.powi(2).ln_1p()` +LL | let _ = (x.powi(3) + 1.0).ln(); + | ^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `x.powi(3).ln_1p()` error: ln(1 + x) can be computed more accurately --> $DIR/floating_point_log.rs:49:13 diff --git a/tests/ui/floating_point_powf.fixed b/tests/ui/floating_point_powf.fixed index 78a9d44829b..b0641a100cd 100644 --- a/tests/ui/floating_point_powf.fixed +++ b/tests/ui/floating_point_powf.fixed @@ -11,7 +11,7 @@ fn main() { let _ = (-3.1f32).exp(); let _ = x.sqrt(); let _ = x.cbrt(); - let _ = x.powi(2); + let _ = x.powi(3); let _ = x.powi(-2); let _ = x.powi(16_777_215); let _ = x.powi(-16_777_215); @@ -30,7 +30,7 @@ fn main() { let _ = (-3.1f64).exp(); let _ = x.sqrt(); let _ = x.cbrt(); - let _ = x.powi(2); + let _ = x.powi(3); let _ = x.powi(-2); let _ = x.powi(-2_147_483_648); let _ = x.powi(2_147_483_647); diff --git a/tests/ui/floating_point_powf.rs b/tests/ui/floating_point_powf.rs index dbc1cac5cb4..a0a2c973900 100644 --- a/tests/ui/floating_point_powf.rs +++ b/tests/ui/floating_point_powf.rs @@ -11,7 +11,7 @@ fn main() { let _ = std::f32::consts::E.powf(-3.1); let _ = x.powf(1.0 / 2.0); let _ = x.powf(1.0 / 3.0); - let _ = x.powf(2.0); + let _ = x.powf(3.0); let _ = x.powf(-2.0); let _ = x.powf(16_777_215.0); let _ = x.powf(-16_777_215.0); @@ -30,7 +30,7 @@ fn main() { let _ = std::f64::consts::E.powf(-3.1); let _ = x.powf(1.0 / 2.0); let _ = x.powf(1.0 / 3.0); - let _ = x.powf(2.0); + let _ = x.powf(3.0); let _ = x.powf(-2.0); let _ = x.powf(-2_147_483_648.0); let _ = x.powf(2_147_483_647.0); diff --git a/tests/ui/floating_point_powf.stderr b/tests/ui/floating_point_powf.stderr index ad5163f0079..2422eb911e9 100644 --- a/tests/ui/floating_point_powf.stderr +++ b/tests/ui/floating_point_powf.stderr @@ -53,8 +53,8 @@ LL | let _ = x.powf(1.0 / 3.0); error: exponentiation with integer powers can be computed more efficiently --> $DIR/floating_point_powf.rs:14:13 | -LL | let _ = x.powf(2.0); - | ^^^^^^^^^^^ help: consider using: `x.powi(2)` +LL | let _ = x.powf(3.0); + | ^^^^^^^^^^^ help: consider using: `x.powi(3)` error: exponentiation with integer powers can be computed more efficiently --> $DIR/floating_point_powf.rs:15:13 @@ -125,8 +125,8 @@ LL | let _ = x.powf(1.0 / 3.0); error: exponentiation with integer powers can be computed more efficiently --> $DIR/floating_point_powf.rs:33:13 | -LL | let _ = x.powf(2.0); - | ^^^^^^^^^^^ help: consider using: `x.powi(2)` +LL | let _ = x.powf(3.0); + | ^^^^^^^^^^^ help: consider using: `x.powi(3)` error: exponentiation with integer powers can be computed more efficiently --> $DIR/floating_point_powf.rs:34:13 diff --git a/tests/ui/floating_point_powi.fixed b/tests/ui/floating_point_powi.fixed new file mode 100644 index 00000000000..0ce6f72535d --- /dev/null +++ b/tests/ui/floating_point_powi.fixed @@ -0,0 +1,12 @@ +// run-rustfix +#![warn(clippy::suboptimal_flops, clippy::imprecise_flops)] + +fn main() { + let one = 1; + let x = 3f32; + let _ = x * x; + let _ = x * x; + // Cases where the lint shouldn't be applied + let _ = x.powi(3); + let _ = x.powi(one + 1); +} diff --git a/tests/ui/floating_point_powi.rs b/tests/ui/floating_point_powi.rs new file mode 100644 index 00000000000..c87e836bedd --- /dev/null +++ b/tests/ui/floating_point_powi.rs @@ -0,0 +1,12 @@ +// run-rustfix +#![warn(clippy::suboptimal_flops, clippy::imprecise_flops)] + +fn main() { + let one = 1; + let x = 3f32; + let _ = x.powi(2); + let _ = x.powi(1 + 1); + // Cases where the lint shouldn't be applied + let _ = x.powi(3); + let _ = x.powi(one + 1); +} diff --git a/tests/ui/floating_point_powi.stderr b/tests/ui/floating_point_powi.stderr new file mode 100644 index 00000000000..ae7bbaa4473 --- /dev/null +++ b/tests/ui/floating_point_powi.stderr @@ -0,0 +1,16 @@ +error: square can be computed more accurately + --> $DIR/floating_point_powi.rs:7:13 + | +LL | let _ = x.powi(2); + | ^^^^^^^^^ help: consider using: `x * x` + | + = note: `-D clippy::imprecise-flops` implied by `-D warnings` + +error: square can be computed more accurately + --> $DIR/floating_point_powi.rs:8:13 + | +LL | let _ = x.powi(1 + 1); + | ^^^^^^^^^^^^^ help: consider using: `x * x` + +error: aborting due to 2 previous errors +