[LIR] Strengthen the check for recurrence variable in popcnt/CTLZ.

Fixes PR33114.
Differential Revision:  https://reviews.llvm.org/D33420

llvm-svn: 303700

1 files changed, 35 insertions, 0 deletions

diff --git a/llvm/test/Transforms/LoopIdiom/pr33114.ll b/llvm/test/Transforms/LoopIdiom/pr33114.ll
new file mode 100644
index 00000000000..fa44d8e31e7
--- /dev/null
+++ b/llvm/test/Transforms/LoopIdiom/pr33114.ll
@@ -0,0 +1,35 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; Check that we're not crashing while looking at the recurrence variable.
+; RUN: opt -S -loop-idiom %s | FileCheck %s
+
+define void @tinkywinky() {
+; CHECK-LABEL: @tinkywinky(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br i1 true, label [[EXIT:%.*]], label [[PH:%.*]]
+; CHECK:       ph:
+; CHECK-NEXT:    [[MYPHI:%.*]] = phi i32 [ 1, [[ENTRY:%.*]] ]
+; CHECK-NEXT:    br label [[IF_END:%.*]]
+; CHECK:       if.end:
+; CHECK-NEXT:    [[PATATINO:%.*]] = ashr i32 [[MYPHI]], undef
+; CHECK-NEXT:    [[TOBOOL:%.*]] = icmp eq i32 [[PATATINO]], 0
+; CHECK-NEXT:    br i1 [[TOBOOL]], label [[EXIT_LOOPEXIT:%.*]], label [[IF_END]]
+; CHECK:       exit.loopexit:
+; CHECK-NEXT:    br label [[EXIT]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret void
+;
+entry:
+  br i1 true, label %exit, label %ph
+
+ph:
+  %myphi = phi i32 [ 1, %entry ]
+  br label %if.end
+
+if.end:
+  %patatino = ashr i32 %myphi, undef
+  %tobool = icmp eq i32 %patatino, 0
+  br i1 %tobool, label %exit, label %if.end
+
+exit:
+  ret void
+}