Update comments and documentation to reflect that GCSE and ValueNumbering are

deprecated by the GVN and GVNPRE passes.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51983 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 10 insertions, 1 deletions

diff --git a/lib/Transforms/Scalar/GCSE.cpp b/lib/Transforms/Scalar/GCSE.cpp
index 35752bb679..94cdcb1400 100644
--- a/lib/Transforms/Scalar/GCSE.cpp
+++ b/lib/Transforms/Scalar/GCSE.cpp
@@ -9,9 +9,12 @@
 //
 // This pass is designed to be a very quick global transformation that
 // eliminates global common subexpressions from a function.  It does this by
-// using an existing value numbering implementation to identify the common
+// using an existing value numbering analysis pass to identify the common
 // subexpressions, eliminating them when possible.
 //
+// This pass is deprecated by the Global Value Numbering pass (which does a
+// better job with its own value numbering).
+//
 //===----------------------------------------------------------------------===//
 
 #define DEBUG_TYPE "gcse"
diff --git a/lib/Transforms/Scalar/GVN.cpp b/lib/Transforms/Scalar/GVN.cpp
index fcfe3c5058..e223281b42 100644
--- a/lib/Transforms/Scalar/GVN.cpp
+++ b/lib/Transforms/Scalar/GVN.cpp
@@ -10,6 +10,9 @@
 // This pass performs global value numbering to eliminate fully redundant
 // instructions.  It also performs simple dead load elimination.
 //
+// Note that this pass does the value numbering itself, it does not use the
+// ValueNumbering analysis passes.
+//
 //===----------------------------------------------------------------------===//
 
 #define DEBUG_TYPE "gvn"
diff --git a/lib/Transforms/Scalar/GVNPRE.cpp b/lib/Transforms/Scalar/GVNPRE.cpp
index 1746fd8025..e0c869fbf8 100644
--- a/lib/Transforms/Scalar/GVNPRE.cpp
+++ b/lib/Transforms/Scalar/GVNPRE.cpp
@@ -16,6 +16,9 @@
 // live ranges, and should be used with caution on platforms that are very 
 // sensitive to register pressure.
 //
+// Note that this pass does the value numbering itself, it does not use the
+// ValueNumbering analysis passes.
+//
 //===----------------------------------------------------------------------===//
 
 #define DEBUG_TYPE "gvnpre"