[InstSimplify] add a phi test with 1 incoming value; NFC

D63489 proposes to change this behavior, but there's no
direct -instsimplify test to verify that the transform exists.

llvm-svn: 363842

1 files changed, 32 insertions, 2 deletions

diff --git a/llvm/test/Transforms/InstSimplify/phi.ll b/llvm/test/Transforms/InstSimplify/phi.ll
index b0040ffeb03..242b7ab87bf 100644
--- a/llvm/test/Transforms/InstSimplify/phi.ll
+++ b/llvm/test/Transforms/InstSimplify/phi.ll
@@ -1,10 +1,21 @@
-; NOTE: Assertions have been autogenerated by update_test_checks.py
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
 ; RUN: opt < %s -instsimplify -S | FileCheck %s
 
 ; PR12189
 define i1 @test1(i32 %x) {
 ; CHECK-LABEL: @test1(
-; CHECK:         ret i1 %e
+; CHECK-NEXT:    br i1 true, label [[A:%.*]], label [[B:%.*]]
+; CHECK:       a:
+; CHECK-NEXT:    [[AA:%.*]] = or i32 [[X:%.*]], 10
+; CHECK-NEXT:    br label [[C:%.*]]
+; CHECK:       b:
+; CHECK-NEXT:    [[BB:%.*]] = or i32 [[X]], 10
+; CHECK-NEXT:    br label [[C]]
+; CHECK:       c:
+; CHECK-NEXT:    [[CC:%.*]] = phi i32 [ [[BB]], [[B]] ], [ [[AA]], [[A]] ]
+; CHECK-NEXT:    [[D:%.*]] = urem i32 [[CC]], 2
+; CHECK-NEXT:    [[E:%.*]] = icmp eq i32 [[D]], 0
+; CHECK-NEXT:    ret i1 [[E]]
 ;
   br i1 true, label %a, label %b
 
@@ -22,3 +33,22 @@ c:
   %e = icmp eq i32 %d, 0
   ret i1 %e
 }
+
+; D63489 - https://reviews.llvm.org/D63489
+; If this single-value phi form needs to be preserved to enable
+; further analysis, then -instsimplify should not be running?
+
+define i32 @lcssa-phi(i32 %x) {
+; CHECK-LABEL: @lcssa-phi(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[END:%.*]]
+; CHECK:       end:
+; CHECK-NEXT:    ret i32 [[X:%.*]]
+;
+entry:
+  br label %end
+
+end:
+  %counter.lcssa = phi i32 [ %x, %entry ]
+  ret i32 %counter.lcssa
+}