Use updated threshold for indirect call bonus

Use updated threshold for indirect call bonus

When considering foo->bar inlining, if there is an indirect call in foo which gets resolved to a direct call (say baz), then we try to inline baz into bar with a threshold T and subtract max(T - Cost(bar->baz), 0) from Cost(foo->bar). This patch uses max(Threshold(bar->baz) - Cost(bar->baz)) instead, where Thresheld(bar->baz) could be different from T due to bonuses or subtractions. Threshold(bar->baz) - Cost(bar->baz) better represents the desirability of inlining baz into bar.

Differential Revision: http://reviews.llvm.org/D14309

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@254945 91177308-0d34-0410-b5e6-96231b3b80d8