Different results in Debug and Release mode compile

[njuffa]

If your code uses floating-point computation, the most likely reason is that FADD dependent upon FMUL will frequently get contracted to FMA (fused multiply-add) in a release build. To confirm that this explains the differences, you can turn off this contraction by building with -fma=false. Since this typically has a negative impact on both accuracy and performance you wouldn’t want to use that for your production build, but it is useful for experiments.