Add test case with PHI node in exit block

The PHI node with multiple incoming edges from inside the region.

Thanks Tobias for coming up with the example. 

llvm-svn: 244456

polly/test/ScopDetect/phi_with_multi_exiting_edges.ll

@@ -0,0 +1,66 @@
+; RUN: opt %loadPolly -polly-detect-unprofitable -polly-detect -analyze -S < %s | FileCheck %s
+;
+; XFAIL: *
+;
+; Region with an exit node that has a PHI node multiple incoming edges from
+; inside the region. Motivation for supporting such cases in Polly.
+;
+;    float test(long n, float A[static const restrict n]) {
+;      float sum = 0;
+;      for (long i = 0; i < n; i += 1)
+;        sum += A[i];
+;      for (long i = 0; i < n; i += 1)
+;        sum += A[i];
+;      return sum;
+;    }
+;
+;
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+
+define float @test(i64 %n, float* noalias nonnull %A) {
+entry:
+  br label %for.cond
+
+for.cond:                                         ; preds = %for.inc, %entry
+  %sum.0 = phi float [ 0.000000e+00, %entry ], [ %add, %for.inc ]
+  %i.0 = phi i64 [ 0, %entry ], [ %add1, %for.inc ]
+  %cmp = icmp slt i64 %i.0, %n
+  br i1 %cmp, label %for.body, label %for.end
+
+for.body:                                         ; preds = %for.cond
+  br label %for.inc
+
+for.inc:                                          ; preds = %for.body
+  %arrayidx = getelementptr inbounds float, float* %A, i64 %i.0
+  %tmp = load float, float* %arrayidx, align 4
+  %add = fadd float %sum.0, %tmp
+  %add1 = add nuw nsw i64 %i.0, 1
+  br label %for.cond
+
+for.end:                                          ; preds = %for.cond
+  %sum.0.lcssa = phi float [ %sum.0, %for.cond ]
+  br label %for.cond.3
+
+for.cond.3:                                       ; preds = %for.inc.8, %for.end
+  %sum.1 = phi float [ %sum.0.lcssa, %for.end ], [ %add7, %for.inc.8 ]
+  %i2.0 = phi i64 [ 0, %for.end ], [ %add9, %for.inc.8 ]
+  %cmp4 = icmp slt i64 %i2.0, %n
+  br i1 %cmp4, label %for.body.5, label %for.end.10
+
+for.body.5:                                       ; preds = %for.cond.3
+  br label %for.inc.8
+
+for.inc.8:                                        ; preds = %for.body.5
+  %arrayidx6 = getelementptr inbounds float, float* %A, i64 %i2.0
+  %tmp1 = load float, float* %arrayidx6, align 4
+  %add7 = fadd float %sum.1, %tmp1
+  %add9 = add nuw nsw i64 %i2.0, 1
+  br label %for.cond.3
+
+for.end.10:                                       ; preds = %for.cond.3
+  %sum.1.lcssa = phi float [ %sum.1, %for.cond.3 ]
+  ret float %sum.1.lcssa
+}
+
+; CHECK: Valid Region for Scop: for.cond => for.end.10