[ScopInfo] Allow invariant loads in branch conditions

In case the value used in a branch condition is a load instruction, assume this
load to be invariant.

llvm-svn: 314146

1 files changed, 10 insertions, 2 deletions

diff --git a/polly/lib/Analysis/ScopInfo.cpp b/polly/lib/Analysis/ScopInfo.cpp
index dbf38042382..2cdf2cba59b 100644
--- a/polly/lib/Analysis/ScopInfo.cpp
+++ b/polly/lib/Analysis/ScopInfo.cpp
@@ -1540,9 +1540,18 @@ bool buildConditionSets(Scop &S, BasicBlock *BB, Value *Condition,
                         TerminatorInst *TI, Loop *L, __isl_keep isl_set *Domain,
                         DenseMap<BasicBlock *, isl::set> &InvalidDomainMap,
                         SmallVectorImpl<__isl_give isl_set *> &ConditionSets) {
+  ScalarEvolution &SE = *S.getSE();
   isl_set *ConsequenceCondSet = nullptr;
 
-  if (auto *PHI = dyn_cast<PHINode>(Condition)) {
+  if (auto Load = dyn_cast<LoadInst>(Condition)) {
+    const SCEV *LHSSCEV = SE.getSCEVAtScope(Load, L);
+    const SCEV *RHSSCEV = SE.getZero(LHSSCEV->getType());
+    bool NonNeg = false;
+    isl_pw_aff *LHS = getPwAff(S, BB, InvalidDomainMap, LHSSCEV, NonNeg);
+    isl_pw_aff *RHS = getPwAff(S, BB, InvalidDomainMap, RHSSCEV, NonNeg);
+    ConsequenceCondSet =
+        buildConditionSet(ICmpInst::ICMP_SLE, LHS, RHS, Domain);
+  } else if (auto *PHI = dyn_cast<PHINode>(Condition)) {
     auto *Unique = dyn_cast<ConstantInt>(
         getUniqueNonErrorValue(PHI, &S.getRegion(), *S.getLI(), *S.getDT()));
 
@@ -1583,7 +1592,6 @@ bool buildConditionSets(Scop &S, BasicBlock *BB, Value *Condition,
     assert(ICond &&
            "Condition of exiting branch was neither constant nor ICmp!");
 
-    ScalarEvolution &SE = *S.getSE();
     LoopInfo &LI = *S.getLI();
     DominatorTree &DT = *S.getDT();
     Region &R = S.getRegion();