Strange Build Error in ConstraintSolver (only in release)

[PlumCantaloupe]

I have run into a strange build error that only presents itself in release mode of a program I am creating (derivative of the softbodies ragdoll demo). (Xcode 4.6.1 using LLVM compiler 4.2 - bullet-2.81-rev2613). Debug seems to have no issues, and I was hoping someone may be able to shed some light onto the arcane error I received, as I am at a loss as to what the problem is or even where to start looking as random commenting of the code seems to shed no light (except that if I remove the setupContactConstraint function entirely the error then jumps to setupRollingFrictionConstraint.

fatal error: error in backend: Cannot select: 0x108d4c110: f32 = ConstantFP<3.000000e+00> [ID=6]
In function: _ZN35btSequentialImpulseConstraintSolver23setupFrictionConstraintER18btSolverConstraintRK9btVector3iiR15btManifoldPointS4_S4_P17btCollisionObjectS8_fff
Command /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang failed with exit code 1

Thanks in advance to anyone that may have some ideas. And thanks to the developers for such an amazing library - having a great deal of fun trying to figure it out.

[PlumCantaloupe]

update: strangely if I change the Code generation optimization level build setting to 'none' the error disappears ...

[PlumCantaloupe]

update 2: keeping the optimization setting to 'fastest' and then changing the 'relax IEEE Compliance to no' also fixes the error. This is definitely arcane for me so I would still definitely appreciate a postulation as to why this might be if anyone has the time. Thanks.