NewGVN: Fix PR 34430 - we need to look through predicateinfo copies to detect self-cycles of phi nodes. We also need to not ignore certain types of arguments when testing whether the phi has a backedge or was originally constant.

llvm-svn: 312510

1 files changed, 48 insertions, 0 deletions

diff --git a/llvm/test/Transforms/NewGVN/pr34430.ll b/llvm/test/Transforms/NewGVN/pr34430.ll
new file mode 100644
index 00000000000..81d18371cb9
--- /dev/null
+++ b/llvm/test/Transforms/NewGVN/pr34430.ll
@@ -0,0 +1,48 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; ModuleID = 'bugpoint-reduced-simplified.bc'
+; RUN: opt < %s -newgvn -S | FileCheck %s
+source_filename = "bugpoint-output-e4c7d0f.bc"
+
+;  Make sure we still properly resolve phi cycles when they involve predicateinfo copies of phis.
+define void @hoge() local_unnamed_addr #0 {
+; CHECK-LABEL: @hoge(
+; CHECK-NEXT:  bb:
+; CHECK-NEXT:    br i1 undef, label [[BB6:%.*]], label [[BB1:%.*]]
+; CHECK:       bb1:
+; CHECK-NEXT:    br label [[BB6]]
+; CHECK:       bb2:
+; CHECK-NEXT:    br i1 true, label [[BB3:%.*]], label [[BB6]]
+; CHECK:       bb3:
+; CHECK-NEXT:    br label [[BB4:%.*]]
+; CHECK:       bb4:
+; CHECK-NEXT:    br i1 undef, label [[BB2:%.*]], label [[BB6]]
+; CHECK:       bb6:
+; CHECK-NEXT:    br label [[BB4]]
+;
+bb:
+  br i1 undef, label %bb6, label %bb1
+
+bb1:                                              ; preds = %bb
+  br label %bb6
+
+bb2:                                              ; preds = %bb4
+  %tmp = icmp slt i8 %tmp5, 7
+  br i1 %tmp, label %bb3, label %bb6
+
+bb3:                                              ; preds = %bb2
+  br label %bb4
+
+bb4:                                              ; preds = %bb6, %bb3
+  %tmp5 = phi i8 [ %tmp5, %bb3 ], [ %tmp7, %bb6 ]
+  br i1 undef, label %bb2, label %bb6
+
+bb6:                                              ; preds = %bb4, %bb2, %bb1, %bb
+  %tmp7 = phi i8 [ %tmp5, %bb4 ], [ %tmp5, %bb2 ], [ 5, %bb1 ], [ undef, %bb ]
+  br label %bb4
+}
+
+attributes #0 = { norecurse noreturn nounwind ssp uwtable "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="penryn" "target-features"="+cx16,+fxsr,+mmx,+sse,+sse2,+sse3,+sse4.1,+ssse3,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+
+!llvm.ident = !{!0}
+
+!0 = !{!"clang version 6.0.0 (http://llvm.org/git/clang.git e649d902285b23af8ba58cb92a739f3bad2723df) (/Users/dannyb/sources/llvm-clean 0abfd30028cbb294ff2c2dd5e2df4ec3fdb6c591)"}