Displaying 1 result from an estimated 1 matches for "a18536ca".
2014 Sep 19
2
[LLVMdev] poison and select
Today I ran into another aspect of the poison problem...
Basically, SimplifyCFG wants to take
expr1 && expr2
and flatten it into
x = expr1
y = expr2
x&y
This isn't safe when expr2 might execute UB. The consequence is that no
LLVM shift instruction is safe to speculatively execute, nor is any
nsw/nuw/exact variant, unless the operands can be proven to be in