https://bugs.llvm.org/show_bug.cgi?id=37778
...shows a miscompile resulting from marking nan builtins as 'const'.
The nan libcalls/builtins take a pointer argument:
http://www.cplusplus.com/reference/cmath/nan-function/
...and the chars dereferenced by that arg are used to fill in the NaN constant payload bits.
"const" means that the pointer argument isn't dereferenced. That's translated to "readnone" in LLVM.
"pure" means that the pointer argument may be dereferenced. That's translated to "readonly" in LLVM.
This change prevents the IR optimizer from killing the lead-up to the nan call here:
double a() {
char buf[4];
buf[0] = buf[1] = buf[2] = '9';
buf[3] = '\0';
return __builtin_nan(buf);
}
...the optimizer isn't currently able to simplify this to a constant as we might hope,
but this patch should solve the miscompile.
Differential Revision: https://reviews.llvm.org/D48134
llvm-svn: 334628
Summary:
r318093 sets fma, fmaf, fmal as const for Gnu and MSVC. Android also
does not set errno for these functions. So mark these const for
Android.
Reviewers: spatel, efriedma, srhines, chh, enh
Subscribers: cfe-commits, llvm-commits
Differential Revision: https://reviews.llvm.org/D44852
llvm-svn: 328552
These just overloads for _Float128. They're supported by GCC 7 and used
by glibc. APFloat support is already there so just add the overloads.
__builtin_copysignf128
__builtin_fabsf128
__builtin_huge_valf128
__builtin_inff128
__builtin_nanf128
__builtin_nansf128
This is the same support that GCC has, according to the documentation,
but limited to _Float128.
llvm-svn: 321948
There are 20 LLVM math intrinsics that correspond to mathlib calls according to the LangRef:
http://llvm.org/docs/LangRef.html#standard-c-library-intrinsics
We were only converting 3 mathlib calls (sqrt, fma, pow) and 12 builtin calls (ceil, copysign,
fabs, floor, fma, fmax, fmin, nearbyint, pow, rint, round, trunc) to their intrinsic-equivalents.
This patch pulls the transforms together and handles all 20 cases. The switch is guarded by a
check for const-ness to make sure we're not doing the transform if errno could possibly be set by
the libcall or builtin.
Differential Revision: https://reviews.llvm.org/D40044
llvm-svn: 319593
cbrt() is always constant because it can't overflow or underflow. Therefore, it can't set errno.
fma() is not always constant because it can overflow or underflow. Therefore, it can set errno.
But we know that it never sets errno on GNU / MSVC, so make it constant in those environments.
Differential Revision: https://reviews.llvm.org/D39641
llvm-svn: 318093
The files are already large, and we may need to add even more RUNs to
distinguish differences based on OS, environment, or other platform things.
llvm-svn: 317583
Sanjay Patel