commit 9ee7123ab462d97a2b242280e9bf0b47883531cb
author Dan Gohman <gohman@apple.com> Wed Feb 17 00:54:58 2010 +0000
committer Dan Gohman <gohman@apple.com> Wed Feb 17 00:54:58 2010 +0000
tree 3588eaffa989e094b90f3caa5a668d725949a594
parent 378c0b35a7b9884f1de2a9762825424fbf1813ac

Fold bswap(undef) to undef.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96432 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Analysis/ConstantFolding.cpp

diff --git a/lib/Analysis/ConstantFolding.cpp b/lib/Analysis/ConstantFolding.cpp
index 6bab5ec..676a846 100644
--- a/lib/Analysis/ConstantFolding.cpp
+++ b/lib/Analysis/ConstantFolding.cpp
@@ -1179,6 +1179,12 @@
       return 0;
     }
     
+    if (isa<UndefValue>(Operands[0])) {
+      if (Name.startswith("llvm.bswap"))
+        return Operands[0];
+      return 0;
+    }
+
     return 0;
   }