Imported Upstream version 6.0.0.172

Former-commit-id: f3cc9b82f3e5bd8f0fd3ebc098f789556b44e9cd

external/llvm/test/Transforms/LoopUnroll/epilog_const_phi.ll

@@ -0,0 +1,65 @@
+; RUN: opt -S -loop-unroll -unroll-runtime < %s | FileCheck %s
+
+; Epilog unroll allows to keep PHI constant value.
+; For the test this means that after unroll XOR could be deleted.
+; Check that we do epilogue reminder here.
+
+; CHECK-LABEL: const_phi_val
+; CHECK:  for.body.epil
+
+; Function Attrs: norecurse nounwind uwtable
+define void @const_phi_val(i32 %i0, i32* nocapture %a) {
+entry:
+  %cmp6 = icmp slt i32 %i0, 1000
+  br i1 %cmp6, label %for.body.preheader, label %for.end
+
+for.body.preheader:                               ; preds = %entry
+  %tmp = sext i32 %i0 to i64
+  br label %for.body
+
+for.body:                                         ; preds = %for.body, %for.body.preheader
+  %indvars.iv = phi i64 [ %tmp, %for.body.preheader ], [ %indvars.iv.next, %for.body ]
+  %s.08 = phi i32 [ 0, %for.body.preheader ], [ %xor, %for.body ]
+  %arrayidx = getelementptr inbounds i32, i32* %a, i64 %indvars.iv
+  store i32 %s.08, i32* %arrayidx, align 4
+  %xor = xor i32 %s.08, 1
+  %indvars.iv.next = add nsw i64 %indvars.iv, 1
+  %exitcond = icmp eq i64 %indvars.iv.next, 1000
+  br i1 %exitcond, label %for.end.loopexit, label %for.body
+
+for.end.loopexit:                                 ; preds = %for.body
+  br label %for.end
+
+for.end:                                          ; preds = %for.end.loopexit, %entry
+  ret void
+}
+
+; When there is no phi with const coming from preheader,
+; there is no need to do epilogue unrolling.
+
+; CHECK-LABEL: var_phi_val
+; CHECK:  for.body.prol
+
+; Function Attrs: norecurse nounwind uwtable
+define void @var_phi_val(i32 %i0, i32* nocapture %a) {
+entry:
+  %cmp6 = icmp slt i32 %i0, 1000
+  br i1 %cmp6, label %for.body.preheader, label %for.end
+
+for.body.preheader:                               ; preds = %entry
+  %tmp = sext i32 %i0 to i64
+  br label %for.body
+
+for.body:                                         ; preds = %for.body, %for.body.preheader
+  %indvars.iv = phi i64 [ %tmp, %for.body.preheader ], [ %indvars.iv.next, %for.body ]
+  %arrayidx = getelementptr inbounds i32, i32* %a, i64 %indvars.iv
+  %indvars.iv.next = add nsw i64 %indvars.iv, 1
+  %exitcond = icmp eq i64 %indvars.iv.next, 1000
+  br i1 %exitcond, label %for.end.loopexit, label %for.body
+
+for.end.loopexit:                                 ; preds = %for.body
+  br label %for.end
+
+for.end:                                          ; preds = %for.end.loopexit, %entry
+  ret void
+}