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Avoid floating-point types in Ieee32::new and Ieee64::new. (#130)

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* Avoid floating-point types in Ieee32::new and Ieee64::new.

This eliminates the need for unsafe code in code that uses Cretonne, a few
instances of unsafe code in Cretonne itself, and eliminates the only instance
of floating point in Cretonne.

* Rename new to with_bits, and new_from_float to with_float.
This commit is contained in:
Dan Gohman
2017-08-02 11:05:49 -07:00
committed by GitHub
parent 6dc5b3e608
commit 39488630f6
2 changed files with 52 additions and 35 deletions
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83
lib/cretonne/src/ir/immediates.rs
View File

@@ -7,9 +7,11 @@
use std::fmt::{self, Display, Formatter};
use std::{i32, u32};
use std::mem;
use std::str::FromStr;
#[cfg(test)]
use std::mem;
/// 64-bit immediate integer operand.
///
/// An `Imm64` operand can also be used to represent immediate values of smaller integer types by
@@ -531,8 +533,14 @@ fn parse_float(s: &str, w: u8, t: u8) -> Result<u64, &'static str> {
}
impl Ieee32 {
/// Create a new `Ieee32` containing the bits of `x`.
pub fn with_bits(x: u32) -> Ieee32 {
Ieee32(x)
}
/// Create a new `Ieee32` representing the number `x`.
pub fn new(x: f32) -> Ieee32 {
#[cfg(test)]
pub fn with_float(x: f32) -> Ieee32 {
Ieee32(unsafe { mem::transmute(x) })
}
}
@@ -556,8 +564,14 @@ impl FromStr for Ieee32 {
}
impl Ieee64 {
/// Create a new `Ieee64` containing the bits of `x`.
pub fn with_bits(x: u64) -> Ieee64 {
Ieee64(x)
}
/// Create a new `Ieee64` representing the number `x`.
pub fn new(x: f64) -> Ieee64 {
#[cfg(test)]
pub fn with_float(x: f64) -> Ieee64 {
Ieee64(unsafe { mem::transmute(x) })
}
}
@@ -714,26 +728,27 @@ mod tests {
#[test]
fn format_ieee32() {
assert_eq!(Ieee32::new(0.0).to_string(), "0.0");
assert_eq!(Ieee32::new(-0.0).to_string(), "-0.0");
assert_eq!(Ieee32::new(1.0).to_string(), "0x1.000000p0");
assert_eq!(Ieee32::new(1.5).to_string(), "0x1.800000p0");
assert_eq!(Ieee32::new(0.5).to_string(), "0x1.000000p-1");
assert_eq!(Ieee32::new(f32::EPSILON).to_string(), "0x1.000000p-23");
assert_eq!(Ieee32::new(f32::MIN).to_string(), "-0x1.fffffep127");
assert_eq!(Ieee32::new(f32::MAX).to_string(), "0x1.fffffep127");
assert_eq!(Ieee32::with_float(0.0).to_string(), "0.0");
assert_eq!(Ieee32::with_float(-0.0).to_string(), "-0.0");
assert_eq!(Ieee32::with_float(1.0).to_string(), "0x1.000000p0");
assert_eq!(Ieee32::with_float(1.5).to_string(), "0x1.800000p0");
assert_eq!(Ieee32::with_float(0.5).to_string(), "0x1.000000p-1");
assert_eq!(Ieee32::with_float(f32::EPSILON).to_string(),
"0x1.000000p-23");
assert_eq!(Ieee32::with_float(f32::MIN).to_string(), "-0x1.fffffep127");
assert_eq!(Ieee32::with_float(f32::MAX).to_string(), "0x1.fffffep127");
// Smallest positive normal number.
assert_eq!(Ieee32::new(f32::MIN_POSITIVE).to_string(),
assert_eq!(Ieee32::with_float(f32::MIN_POSITIVE).to_string(),
"0x1.000000p-126");
// Subnormals.
assert_eq!(Ieee32::new(f32::MIN_POSITIVE / 2.0).to_string(),
assert_eq!(Ieee32::with_float(f32::MIN_POSITIVE / 2.0).to_string(),
"0x0.800000p-126");
assert_eq!(Ieee32::new(f32::MIN_POSITIVE * f32::EPSILON).to_string(),
assert_eq!(Ieee32::with_float(f32::MIN_POSITIVE * f32::EPSILON).to_string(),
"0x0.000002p-126");
assert_eq!(Ieee32::new(f32::INFINITY).to_string(), "+Inf");
assert_eq!(Ieee32::new(f32::NEG_INFINITY).to_string(), "-Inf");
assert_eq!(Ieee32::new(f32::NAN).to_string(), "+NaN");
assert_eq!(Ieee32::new(-f32::NAN).to_string(), "-NaN");
assert_eq!(Ieee32::with_float(f32::INFINITY).to_string(), "+Inf");
assert_eq!(Ieee32::with_float(f32::NEG_INFINITY).to_string(), "-Inf");
assert_eq!(Ieee32::with_float(f32::NAN).to_string(), "+NaN");
assert_eq!(Ieee32::with_float(-f32::NAN).to_string(), "-NaN");
// Construct some qNaNs with payloads.
assert_eq!(Ieee32(0x7fc00001).to_string(), "+NaN:0x1");
assert_eq!(Ieee32(0x7ff00001).to_string(), "+NaN:0x300001");
@@ -815,27 +830,29 @@ mod tests {
#[test]
fn format_ieee64() {
assert_eq!(Ieee64::new(0.0).to_string(), "0.0");
assert_eq!(Ieee64::new(-0.0).to_string(), "-0.0");
assert_eq!(Ieee64::new(1.0).to_string(), "0x1.0000000000000p0");
assert_eq!(Ieee64::new(1.5).to_string(), "0x1.8000000000000p0");
assert_eq!(Ieee64::new(0.5).to_string(), "0x1.0000000000000p-1");
assert_eq!(Ieee64::new(f64::EPSILON).to_string(),
assert_eq!(Ieee64::with_float(0.0).to_string(), "0.0");
assert_eq!(Ieee64::with_float(-0.0).to_string(), "-0.0");
assert_eq!(Ieee64::with_float(1.0).to_string(), "0x1.0000000000000p0");
assert_eq!(Ieee64::with_float(1.5).to_string(), "0x1.8000000000000p0");
assert_eq!(Ieee64::with_float(0.5).to_string(), "0x1.0000000000000p-1");
assert_eq!(Ieee64::with_float(f64::EPSILON).to_string(),
"0x1.0000000000000p-52");
assert_eq!(Ieee64::new(f64::MIN).to_string(), "-0x1.fffffffffffffp1023");
assert_eq!(Ieee64::new(f64::MAX).to_string(), "0x1.fffffffffffffp1023");
assert_eq!(Ieee64::with_float(f64::MIN).to_string(),
"-0x1.fffffffffffffp1023");
assert_eq!(Ieee64::with_float(f64::MAX).to_string(),
"0x1.fffffffffffffp1023");
// Smallest positive normal number.
assert_eq!(Ieee64::new(f64::MIN_POSITIVE).to_string(),
assert_eq!(Ieee64::with_float(f64::MIN_POSITIVE).to_string(),
"0x1.0000000000000p-1022");
// Subnormals.
assert_eq!(Ieee64::new(f64::MIN_POSITIVE / 2.0).to_string(),
assert_eq!(Ieee64::with_float(f64::MIN_POSITIVE / 2.0).to_string(),
"0x0.8000000000000p-1022");
assert_eq!(Ieee64::new(f64::MIN_POSITIVE * f64::EPSILON).to_string(),
assert_eq!(Ieee64::with_float(f64::MIN_POSITIVE * f64::EPSILON).to_string(),
"0x0.0000000000001p-1022");
assert_eq!(Ieee64::new(f64::INFINITY).to_string(), "+Inf");
assert_eq!(Ieee64::new(f64::NEG_INFINITY).to_string(), "-Inf");
assert_eq!(Ieee64::new(f64::NAN).to_string(), "+NaN");
assert_eq!(Ieee64::new(-f64::NAN).to_string(), "-NaN");
assert_eq!(Ieee64::with_float(f64::INFINITY).to_string(), "+Inf");
assert_eq!(Ieee64::with_float(f64::NEG_INFINITY).to_string(), "-Inf");
assert_eq!(Ieee64::with_float(f64::NAN).to_string(), "+NaN");
assert_eq!(Ieee64::with_float(-f64::NAN).to_string(), "-NaN");
// Construct some qNaNs with payloads.
assert_eq!(Ieee64(0x7ff8000000000001).to_string(), "+NaN:0x1");
assert_eq!(Ieee64(0x7ffc000000000001).to_string(),

4
lib/frontend/src/ssa.rs
View File

@@ -490,9 +490,9 @@ impl<Variable> SSABuilder<Variable>
let val = if ty.is_int() {
dfg.ins(&mut cur).iconst(ty, 0)
} else if ty == F32 {
dfg.ins(&mut cur).f32const(Ieee32::new(0.0))
dfg.ins(&mut cur).f32const(Ieee32::with_bits(0))
} else if ty == F64 {
dfg.ins(&mut cur).f64const(Ieee64::new(0.0))
dfg.ins(&mut cur).f64const(Ieee64::with_bits(0))
} else {
panic!("value used but never declared and initialization not supported")
};