[PowerPC] initialize SchedModel according to platform

[shchenz]

Summary

This is a typo fix.
We should initialize SchedModel according to platform.

[jsji]

LGTM. Thanks for fixing this bug.

llvm/trunk/lib/Target/PowerPC/PPCCTRLoops.cpp

bool PPCCTRLoops::runOnFunction(Function &F) {
   LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
   SE = &getAnalysis<ScalarEvolutionWrapperPass>().getSE();
   DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
   TTI = &getAnalysis<TargetTransformInfoWrapperPass>().getTTI(F);
   DL = &F.getParent()->getDataLayout();
   auto *TLIP = getAnalysisIfAvailable<TargetLibraryInfoWrapperPass>();
   LibInfo = TLIP ? &TLIP->getTLI() : nullptr;
   PreserveLCSSA = mustPreserveAnalysisID(LCSSAID);
+  SchedModel.init(STI);
 
   bool MadeChange = false;
 
   for (LoopInfo::iterator I = LI->begin(), E = LI->end();
        I != E; ++I) {
     Loop *L = *I;
     if (!L->getParentLoop())
       MadeChange |= convertToCTRLoop(L);

llvm/trunk/test/CodeGen/PowerPC/ctrloop-shortLoops.ll

for.end:                                          ; preds = %if.end
   %conv = zext i8 %b.1 to i32
   ret i32 %conv
 }
 
 ; On core a2q, IssueWidth is 1. On core pwr8, IssueWidth is 8.
 ; a2q should use mtctr, but pwr8 should not use mtctr.
 define signext i32 @testTripCount5() {
 ; CHECK-LABEL: testTripCount5:
-; CHECK-PWR8: mtctr
+; CHECK-PWR8-NOT: mtctr
 ; CHECK-A2Q: mtctr
  
 entry:
   %.prea = load i32, i32* @a, align 4
   %.preb = load i32, i32* @b, align 4
   %.prec = load i32, i32* @c, align 4
   %.pred = load i32, i32* @d, align 4
   %.pree = load i32, i32* @e, align 4