File: builtin-nan-legacy.c

package info (click to toggle)
llvm-toolchain-13 1%3A13.0.1-6~deb11u1
  • links: PTS, VCS
  • area: main
  • in suites: bullseye
  • size: 1,418,812 kB
  • sloc: cpp: 5,290,827; ansic: 996,570; asm: 544,593; python: 188,212; objc: 72,027; lisp: 30,291; f90: 25,395; sh: 24,900; javascript: 9,780; pascal: 9,398; perl: 7,484; ml: 5,432; awk: 3,523; makefile: 2,892; xml: 953; cs: 573; fortran: 539
file content (21 lines) | stat: -rw-r--r-- 792 bytes parent folder | download | duplicates (19) 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
 
// RUN: %clang -target mipsel-unknown-linux -mnan=legacy -emit-llvm -S %s -o - | FileCheck %s
// CHECK: float 0x7FFC000000000000, float 0x7FF8000000000000
// CHECK: double 0x7FF4000000000000, double 0x7FF8000000000000

// The first line shows an unintended consequence.
// __builtin_nan() creates a legacy QNAN double with an empty payload
// (the first bit of the significand is clear to indicate quiet, so
// the second bit of the payload is set to maintain NAN-ness).
// The value is then truncated, but llvm::APFloat does not know about
// the inverted quiet bit, so it sets the first bit on conversion
// to indicate 'quiet' independently of the setting in clang.

float f[] = {
  __builtin_nan(""),
  __builtin_nans(""),
};

double d[] = {
  __builtin_nan(""),
  __builtin_nans(""),
};