llvm-project

c8c20662 - ValueTracking: Improve frexp known range from dominating conditions (#206927)

ValueTracking: Improve frexp known range from dominating conditions (#206927) Try to restrict the known range of the exponent result of llvm.frexp based on dominating conditions. Identify comparisons that imply the incoming value cannot introduce an overflow in a downstream ldexp use. This pattern appears in the implementation of some complex math functions and allows finite only math to prune out more edge case paths. One attributor test for ldexp regresses due to the switch from computeKnownBits to computeConstantRange. computeConstantRange does not try to handle non-splat vector constants for the binary operators. As a side effect, this also improves knowing that ldexp can't introduce overflow for the 0 case.