Do not add PHIs with no users when creating LCSSA form. Patch by Andrew Clinton.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127674 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 38 insertions, 2 deletions

diff --git a/test/Transforms/LCSSA/2006-06-03-IncorrectIDFPhis.ll b/test/Transforms/LCSSA/2006-06-03-IncorrectIDFPhis.ll
index 7a80f80..1534585 100644
--- a/test/Transforms/LCSSA/2006-06-03-IncorrectIDFPhis.ll
+++ b/test/Transforms/LCSSA/2006-06-03-IncorrectIDFPhis.ll
@@ -1,7 +1,5 @@
 ; RUN: opt < %s -loop-simplify -lcssa -S | \
 ; RUN:   grep {%%SJE.0.0.lcssa = phi .struct.SetJmpMapEntry}
-; RUN: opt < %s -loop-simplify -lcssa -S | \
-; RUN:   grep {%%SJE.0.0.lcssa1 = phi .struct.SetJmpMapEntry}
 
         %struct.SetJmpMapEntry = type { i8*, i32, %struct.SetJmpMapEntry* }
 
diff --git a/test/Transforms/LCSSA/unused-phis.ll b/test/Transforms/LCSSA/unused-phis.ll
new file mode 100644
index 0000000..aa2ab96
--- /dev/null
+++ b/test/Transforms/LCSSA/unused-phis.ll
@@ -0,0 +1,38 @@
+; RUN: opt < %s -lcssa -S | FileCheck %s
+; CHECK: exit1:
+; CHECK: .lcssa =
+; CHECK: exit2:
+; CHECK: .lcssa2 =
+; CHECK: exit3:
+; CHECK-NOT: .lcssa1 =
+
+; Test to ensure that when there are multiple exit blocks, PHI nodes are
+; only inserted by LCSSA when there is a use dominated by a given exit
+; block.
+
+declare void @printf(i32 %i)
+
+define i32 @unused_phis() nounwind {
+entry:
+  br label %loop
+
+loop:
+  %i = phi i32 [0, %entry], [1, %then2]
+  br i1 undef, label %exit1, label %then1
+
+then1:
+  br i1 undef, label %exit2, label %then2
+
+then2:
+  br i1 undef, label %exit3, label %loop
+
+exit1:
+  call void @printf(i32 %i)
+  ret i32 %i
+
+exit2:
+  ret i32 %i
+
+exit3:
+  ret i32 0
+}