[llvm-dev] changes in i1 xor

[Carlo Kok via llvm-dev]

After updating from ~october 2015 I noticed there were changes in how i1 
works. This method used to print "1", now "254":

define i32 @"main"()  {
BasicBlock0:
   %x = alloca i1
   store i1 true, i1* %x
   %5 = load i1, i1* %x
   %6 = xor i1 %5, true
   call void (%._Foundation.NSString*, ...) @NSLog(%NSString* bitcast 
(%NSConstantString* @_unnamed_cfstring_1 to %NSString*), i1 %6)
   ret i32 0
}

The %6 = xor i1 %5, true    results in the value 254 being stored, while 
it used to be 0.

is this as designed and some undefined behavior I was depending on, or a 
bug?

When running it through the optimizer it does work (becomes i1 false).


--
Carlo Kok