void ScalarEvolution::forgetLoopPHIs(const Loop *L) {
BasicBlock *Header = L->getHeader();
+ // Push all Loop-header PHIs onto the Worklist stack, except those
+ // that are presently represented via a SCEVUnknown. SCEVUnknown for
+ // a PHI either means that it has an unrecognized structure, or it's
+ // a PHI that's in the progress of being computed by createNodeForPHI.
+ // In the former case, additional loop trip count information isn't
+ // going to change anything. In the later case, createNodeForPHI will
+ // perform the necessary updates on its own when it gets to that point.
SmallVector<Instruction *, 16> Worklist;
for (BasicBlock::iterator I = Header->begin();
- PHINode *PN = dyn_cast<PHINode>(I); ++I)
- Worklist.push_back(PN);
+ PHINode *PN = dyn_cast<PHINode>(I); ++I) {
+ std::map<SCEVCallbackVH, SCEVHandle>::iterator It = Scalars.find((Value*)I);
+ if (It != Scalars.end() && !isa<SCEVUnknown>(It->second))
+ Worklist.push_back(PN);
+ }
while (!Worklist.empty()) {
Instruction *I = Worklist.pop_back_val();
--- /dev/null
+; RUN: llvm-as < %s | opt -indvars | llvm-dis | grep {120, %bb2.bb3_crit_edge}
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64"
+target triple = "i686-pc-linux-gnu"
+
+; Indvars should be able to compute an exit value for %tmp1.
+
+define i32 @testcase(i5 zeroext %k) nounwind readnone {
+entry:
+ br i1 false, label %bb3, label %bb.nph
+
+bb.nph: ; preds = %entry
+ br label %bb
+
+bb: ; preds = %bb2, %bb.nph
+ %result2 = phi i32 [ %tmp1, %bb2 ], [ 0, %bb.nph ] ; <i32> [#uses=1]
+ %k_01 = phi i5 [ %indvar_next1, %bb2 ], [ 0, %bb.nph ] ; <i5> [#uses=2]
+ %tmp2 = zext i5 %k_01 to i32 ; <i32> [#uses=1]
+ %tmp1 = add i32 %tmp2, %result2 ; <i32> [#uses=2]
+ %indvar_next1 = add i5 %k_01, 1 ; <i5> [#uses=2]
+ br label %bb2
+
+bb2: ; preds = %bb
+ %phitmp = icmp eq i5 %indvar_next1, -16 ; <i1> [#uses=1]
+ br i1 %phitmp, label %bb2.bb3_crit_edge, label %bb
+
+bb2.bb3_crit_edge: ; preds = %bb2
+ br label %bb3
+
+bb3: ; preds = %bb2.bb3_crit_edge, %entry
+ %result.lcssa = phi i32 [ %tmp1, %bb2.bb3_crit_edge ], [ 0, %entry ] ; <i32> [#uses=1]
+ ret i32 %result.lcssa
+}