The implementation of an float ordered <= looks buggy, but maybe I’m not reading the assembly right. This is lesf2vfp.S in compiler-rt, and it has this code:
// extern int __lesf2vfp(float a, float b); // // Returns one iff a <= b and neither is NaN. // Uses Darwin calling convention where single precision arguments are passsed // like 32-bit ints // DEFINE_COMPILERRT_FUNCTION(__lesf2vfp) fmsr s14, r0 // move from GPR 0 to float register fmsr s15, r1 // move from GPR 1 to float register fcmps s14, s15 fmstat movls r0, #1 // set result register to 1 if equal movhi r0, #0 bx lr
If I read this right, the high bits of r0 are always cleared (by the movhi) while the low bits are conditionally set to 1 (by the movls), but there’s nothing to clear the r0’s low bits in the false case. Is this a bug or have I misunderstood the assembly?