Imported Upstream version 5.18.0.246

Former-commit-id: 0c7ce5b1a7851e13f22acfd379b7f9fb304e4833

external/llvm/test/Analysis/ScalarEvolution/2012-05-18-LoopPredRecurse.ll

@@ -0,0 +1,31 @@
+; RUN: opt < %s -iv-users -S -disable-output
+; RUN: opt < %s -passes='require<ivusers>' -S -disable-output
+;
+; PR12868: Infinite recursion:
+; getUDivExpr()->getZeroExtendExpr()->isLoopBackedgeGuardedBy()
+;
+; We actually want SCEV simplification to fail gracefully in this
+; case, so there's no output to check, just the absence of stack overflow.
+
+@c = common global i8 0, align 1
+
+define i32 @func() {
+entry:
+  br label %for.cond
+
+for.cond:                                         ; preds = %for.body, %entry
+  %storemerge = phi i8 [ -1, %entry ], [ %inc, %for.body ]
+  %ui.0 = phi i32 [ undef, %entry ], [ %div, %for.body ]
+  %tobool = icmp eq i8 %storemerge, 0
+  br i1 %tobool, label %for.end, label %for.body
+
+for.body:                                         ; preds = %for.cond
+  %conv = sext i8 %storemerge to i32
+  %div = lshr i32 %conv, 1
+  %tobool2 = icmp eq i32 %div, 0
+  %inc = add i8 %storemerge, 1
+  br i1 %tobool2, label %for.cond, label %for.end
+
+for.end:                                          ; preds = %for.body, %for.cond
+  ret i32 0
+}