SCEVHandle GetExpressionSCEV(Instruction *E, Loop *L);
void OptimizeIndvars(Loop *L);
+ bool FindIVForUser(ICmpInst *Cond, IVStrideUse *&CondUse,
+ const SCEVHandle *&CondStride);
unsigned CheckForIVReuse(const SCEVHandle&, IVExpr&, const Type*,
const std::vector<BasedUser>& UsersToProcess);
// different starting values, into different PHIs.
}
+/// FindIVForUser - If Cond has an operand that is an expression of an IV,
+/// set the IV user and stride information and return true, otherwise return
+/// false.
+bool LoopStrengthReduce::FindIVForUser(ICmpInst *Cond, IVStrideUse *&CondUse,
+ const SCEVHandle *&CondStride) {
+ for (unsigned Stride = 0, e = StrideOrder.size(); Stride != e && !CondUse;
+ ++Stride) {
+ std::map<SCEVHandle, IVUsersOfOneStride>::iterator SI =
+ IVUsesByStride.find(StrideOrder[Stride]);
+ assert(SI != IVUsesByStride.end() && "Stride doesn't exist!");
+
+ for (std::vector<IVStrideUse>::iterator UI = SI->second.Users.begin(),
+ E = SI->second.Users.end(); UI != E; ++UI)
+ if (UI->User == Cond) {
+ // NOTE: we could handle setcc instructions with multiple uses here, but
+ // InstCombine does it as well for simple uses, it's not clear that it
+ // occurs enough in real life to handle.
+ CondUse = &*UI;
+ CondStride = &SI->first;
+ return true;
+ }
+ }
+ return false;
+}
+
// OptimizeIndvars - Now that IVUsesByStride is set up with all of the indvar
// uses in the loop, look to see if we can eliminate some, in favor of using
// common indvars for the different uses.
IVStrideUse *CondUse = 0;
const SCEVHandle *CondStride = 0;
- for (unsigned Stride = 0, e = StrideOrder.size(); Stride != e && !CondUse;
- ++Stride) {
- std::map<SCEVHandle, IVUsersOfOneStride>::iterator SI =
- IVUsesByStride.find(StrideOrder[Stride]);
- assert(SI != IVUsesByStride.end() && "Stride doesn't exist!");
-
- for (std::vector<IVStrideUse>::iterator UI = SI->second.Users.begin(),
- E = SI->second.Users.end(); UI != E; ++UI)
- if (UI->User == Cond) {
- CondUse = &*UI;
- CondStride = &SI->first;
- // NOTE: we could handle setcc instructions with multiple uses here, but
- // InstCombine does it as well for simple uses, it's not clear that it
- // occurs enough in real life to handle.
- break;
- }
- }
- if (!CondUse) return; // setcc doesn't use the IV.
+ if (!FindIVForUser(Cond, CondUse, CondStride))
+ return; // setcc doesn't use the IV.
+
// It's possible for the setcc instruction to be anywhere in the loop, and
// possible for it to have multiple users. If it is not immediately before