similar to: [LLVMdev] llvm seg fault when specifying addRequiredTransitive in module pass

I am having a hard time figuring out the difference between addRequired and addRequiredTransitive. Could someone please clarify the difference? Let's say I have a function pass P1 that relies on a function pass P2. P1 computes some sort of analysis on a function F and P2 uses that analysis when it processes F. Does that mean that I should use addRequiredTransitive? Thanks, Ryan

On Mar 31, 2010, at 2:53 PM, Trevor Harmon wrote: > I'm a bit confused about the distinction between addRequired and > addRequiredTransitive in AnalysisUsage. From PassAnalysisSupport.h: > > "REQUIRES (must be available when the pass runs), REQUIRES TRANSITIVE > (must be available throughout the lifetime of the pass)." > > The part that's confusing me

On Fri Apr 02 00:37:03 +0200 2010, Trevor Harmon wrote: > On Mar 31, 2010, at 3:13 PM, Owen Anderson wrote: > > Others, like MemoryDependenceAnalysis, are "lazy." MDA > > specifically does NOT compute results in its runOnFunction(), > > instead computing results on-demand when a user queries it. Because > > MDA depends on AA, we must ensure that, as long as

On Mar 31, 2010, at 3:13 PM, Owen Anderson wrote: > Some analyses, like Andersen's AA, do all their computation in their > runOnFunction(). Therefore, anything they depended on can be > destroyed after the runOnFunction() returns. What about AA itself? Would addRequired<AliasAnalysis> keep AliasAnalysis alive (but allow AliasAnalysis's dependencies to die)? >

Hi, I'm a bit confused about the distinction between addRequired and addRequiredTransitive in AnalysisUsage. From PassAnalysisSupport.h: "REQUIRES (must be available when the pass runs), REQUIRES TRANSITIVE (must be available throughout the lifetime of the pass)." The part that's confusing me is "must be available when the pass runs". I don't see how