mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-09-07 16:54:48 +00:00
Add a comment about why ScalarEvolution doesn't recognize non-loop PHIs
even when they're obvious. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@75632 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
parent
93990d775e
commit
a653fc5f6b
@ -2402,6 +2402,10 @@ const SCEV *ScalarEvolution::createNodeForPHI(PHINode *PN) {
|
||||
return SymbolicName;
|
||||
}
|
||||
|
||||
// It's tempting to recognize PHIs with a unique incoming value, however
|
||||
// this leads passes like indvars to break LCSSA form. Fortunately, such
|
||||
// PHIs are rare, as instcombine zaps them.
|
||||
|
||||
// If it's not a loop phi, we can't handle it yet.
|
||||
return getUnknown(PN);
|
||||
}
|
||||
|
Loading…
Reference in New Issue
Block a user