When int x == INT_MIN, the behaviour of `-x` is undefined.
This causes a crash when isnan is inlined into code instrumented
for Clang's or GCC's -ftrapv, -fsanitize=signed-integer-overflow,
-fsanitize=undefined or similar.
Instead of mucking about with `int` and `unsigned`,
just use `unsigned` throughout the body of isnan.
For unsigned types, all the same arithmetic can be used,
and it is always well-defined and uses two's complement
for negation, which is exactly the same as these platforms'
signed arithmetic that this code already assumes.
Note that there are some inconsistencies in the code of the various
isnan variants, such as whether integer literals are suffixed with `u`
when promoted to `unsigned int` anyway and whether the "true" return
value is 1 or -1. This patch leaves these inconsistencies intact.
Signed-off-by: Oleg Oshmyan <chor...@inbox.lv>
---
mingw-w64-headers/crt/math.h | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/mingw-w64-headers/crt/math.h b/mingw-w64-headers/crt/math.h
index 59560a3..79f671f 100644
--- a/mingw-w64-headers/crt/math.h
+++ b/mingw-w64-headers/crt/math.h
@@ -521,14 +521,14 @@ __mingw_choose_expr (
\
{
#if defined(__x86_64__) || defined(_AMD64_) || defined(__arm__) ||
defined(_ARM_) || defined(__aarch64__) || defined(_ARM64_)
__mingw_dbl_type_t hlp;
- int l, h;
+ unsigned int l, h;
hlp.x = _x;
l = hlp.lh.low;
h = hlp.lh.high & 0x7fffffff;
- h |= (unsigned int) (l | -l) >> 31;
+ h |= (l | -l) >> 31;
h = 0x7ff00000 - h;
- return (int) ((unsigned int) h) >> 31;
+ return (int) h >> 31;
#elif defined(__i386__) || defined(_X86_)
unsigned short sw;
__asm__ __volatile__ ("fxam;"
@@ -542,12 +542,12 @@ __mingw_choose_expr (
\
{
#if defined(__x86_64__) || defined(_AMD64_) || defined(__arm__) ||
defined(_ARM_) || defined(__aarch64__) || defined(_ARM64_)
__mingw_flt_type_t hlp;
- int i;
+ unsigned int i;
hlp.x = _x;
i = hlp.val & 0x7fffffff;
i = 0x7f800000 - i;
- return (int) (((unsigned int) i) >> 31);
+ return (int) (i >> 31);
#elif defined(__i386__) || defined(_X86_)
unsigned short sw;
__asm__ __volatile__ ("fxam;"
@@ -561,14 +561,14 @@ __mingw_choose_expr (
\
{
#if defined(__x86_64__) || defined(_AMD64_)
__mingw_ldbl_type_t ld;
- int xx, signexp;
+ unsigned int xx, signexp;
ld.x = _x;
signexp = (ld.lh.sign_exponent & 0x7fff) << 1;
- xx = (int) (ld.lh.low | (ld.lh.high & 0x7fffffffu)); /* explicit */
- signexp |= (unsigned int) (xx | (-xx)) >> 31;
+ xx = ld.lh.low | (ld.lh.high & 0x7fffffffu);
+ signexp |= (xx | (-xx)) >> 31;
signexp = 0xfffe - signexp;
- return (int) ((unsigned int) signexp) >> 16;
+ return (int) signexp >> 16;
#elif defined(__arm__) || defined(_ARM_) || defined(__aarch64__) ||
defined(_ARM64_)
return __isnan(_x);
#elif defined(__i386__) || defined(_X86_)
--
2.36.1.windows.1
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