Fix a bug in LazyValueInfo that CorrelatedValuePropagation exposed: In the LVI lattice, undef and the full set ConstantRange should not

be treated as equivalent.

llvm-svn: 112843

2 files changed, 25 insertions, 4 deletions

diff --git a/llvm/lib/Analysis/LazyValueInfo.cpp b/llvm/lib/Analysis/LazyValueInfo.cpp
index f6f715e4df3..ff98bf97711 100644
--- a/llvm/lib/Analysis/LazyValueInfo.cpp
+++ b/llvm/lib/Analysis/LazyValueInfo.cpp
@@ -173,10 +173,6 @@ public:
     assert(isUndefined());
     if (NewR.isEmptySet())
       return markOverdefined();
-    else if (NewR.isFullSet()) {
-      Tag = undefined;
-      return true;
-    }
     
     Tag = constantrange;
     Range = NewR;
diff --git a/llvm/test/Transforms/CorrelatedValuePropagation/2010-09-02-Trunc.ll b/llvm/test/Transforms/CorrelatedValuePropagation/2010-09-02-Trunc.ll
new file mode 100644
index 00000000000..f2553dc2ca1
--- /dev/null
+++ b/llvm/test/Transforms/CorrelatedValuePropagation/2010-09-02-Trunc.ll
@@ -0,0 +1,25 @@
+; RUN: opt -S < %s -correlated-propagation | FileCheck %s
+
+; CHECK: @check
+define i16 @test(i32 %a, i1 %b) {
+entry:
+  %c = icmp eq i32 %a, 0
+  br i1 %c, label %left, label %right
+
+right:
+  %d = trunc i32 %a to i1
+  br label %merge
+
+left:
+  br i1 %b, label %merge, label %other
+
+other:
+  ret i16 23
+
+merge:
+  %f = phi i1 [%b, %left], [%d, %right]
+; CHECK: select i1 %f, i16 1, i16 0 
+  %h = select i1 %f, i16 1, i16 0 
+; CHECK: ret i16 %h
+  ret i16 %h
+}
\ No newline at end of file