[LV] Fix PR36983. For a given recurrence, fix all phis in exit block

There could be more than one PHIs in exit block using same loop recurrence.
Don't assume there is only one and fix each user.

Differential Revision: https://reviews.llvm.org/D47788

llvm-svn: 334271

1 files changed, 24 insertions, 0 deletions

diff --git a/llvm/test/Transforms/LoopVectorize/pr36983.ll b/llvm/test/Transforms/LoopVectorize/pr36983.ll
new file mode 100644
index 00000000000..71b17192255
--- /dev/null
+++ b/llvm/test/Transforms/LoopVectorize/pr36983.ll
@@ -0,0 +1,24 @@
+; RUN: opt < %s -loop-vectorize -S | FileCheck %s
+
+; There could be more than one LCSSA PHIs in loop exit block.
+
+; CHECK-LABEL: bb1.bb3_crit_edge:
+; CHECK: %_tmp133.lcssa1 = phi i16 [ %scalar.recur, %bb2 ], [ %vector.recur.extract.for.phi, %middle.block ]
+; CHECK: %_tmp133.lcssa = phi i16 [ %scalar.recur, %bb2 ], [ %vector.recur.extract.for.phi, %middle.block ]
+
+define void @f1() {
+bb2.lr.ph:
+  br label %bb2
+
+bb2:                                              ; preds = %bb2, %bb2.lr.ph
+  %_tmp132 = phi i16 [ 0, %bb2.lr.ph ], [ %_tmp10, %bb2 ]
+  %_tmp133 = phi i16 [ undef, %bb2.lr.ph ], [ %_tmp10, %bb2 ]
+  %_tmp10 = sub nsw i16 %_tmp132, 1
+  %_tmp15 = icmp ne i16 %_tmp10, 0
+  br i1 %_tmp15, label %bb2, label %bb1.bb3_crit_edge
+
+bb1.bb3_crit_edge:                                ; preds = %bb2
+  %_tmp133.lcssa1 = phi i16 [ %_tmp133, %bb2 ]
+  %_tmp133.lcssa = phi i16 [ %_tmp133, %bb2 ]
+  ret void
+}