diff options
Diffstat (limited to 'src/lj_vmmath.c')
| -rw-r--r-- | src/lj_vmmath.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/src/lj_vmmath.c b/src/lj_vmmath.c index b6cc60ba..d0febd81 100644 --- a/src/lj_vmmath.c +++ b/src/lj_vmmath.c @@ -36,6 +36,17 @@ LJ_FUNCA double lj_wrap_fmod(double x, double y) { return fmod(x, y); } /* -- Helper functions ---------------------------------------------------- */ +/* Required to prevent the C compiler from applying FMA optimizations. +** +** Yes, there's -ffp-contract and the FP_CONTRACT pragma ... in theory. +** But the current state of C compilers is a mess in this regard. +** Also, this function is not performance sensitive at all. +*/ +LJ_NOINLINE static double lj_vm_floormul(double x, double y) +{ + return lj_vm_floor(x / y) * y; +} + double lj_vm_foldarith(double x, double y, int op) { switch (op) { @@ -43,7 +54,7 @@ double lj_vm_foldarith(double x, double y, int op) case IR_SUB - IR_ADD: return x-y; break; case IR_MUL - IR_ADD: return x*y; break; case IR_DIV - IR_ADD: return x/y; break; - case IR_MOD - IR_ADD: return x-lj_vm_floor(x/y)*y; break; + case IR_MOD - IR_ADD: return x-lj_vm_floormul(x, y); break; case IR_POW - IR_ADD: return pow(x, y); break; case IR_NEG - IR_ADD: return -x; break; case IR_ABS - IR_ADD: return fabs(x); break; |