Add FastDSE, a new algorithm for doing dead store elimination. This algorithm is not as accurate

as the current DSE, but it only a linear scan over each block, rather than quadratic.  Eventually
(once it has been improved somewhat), this will replace the current DSE.

NOTE: This has not yet been extensively tested.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@38517 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 8 insertions, 0 deletions

diff --git a/include/llvm/LinkAllPasses.h b/include/llvm/LinkAllPasses.h
index be98f074b7..b445ba05be 100644
--- a/include/llvm/LinkAllPasses.h
+++ b/include/llvm/LinkAllPasses.h
@@ -61,6 +61,7 @@ namespace {
       (void) llvm::createDeadStoreEliminationPass();
       (void) llvm::createDeadTypeEliminationPass();
       (void) llvm::createEdgeProfilerPass();
+      (void) llvm::createFastDeadStoreEliminationPass();
       (void) llvm::createFunctionInliningPass();
       (void) llvm::createFunctionProfilerPass();
       (void) llvm::createGCSEPass();
diff --git a/include/llvm/Transforms/Scalar.h b/include/llvm/Transforms/Scalar.h
index 948d6b5aae..ff12dc9ab7 100644
--- a/include/llvm/Transforms/Scalar.h
+++ b/include/llvm/Transforms/Scalar.h
@@ -325,6 +325,13 @@ FunctionPass *createGVNPREPass();
 
 //===----------------------------------------------------------------------===//
 //
+// FastDeadStoreElimination - This pass deletes stores that are post-dominated by
+// must-aliased stores and are not loaded used between the stores.
+//
+FunctionPass *createFastDeadStoreEliminationPass();
+
+//===----------------------------------------------------------------------===//
+//
 // CodeGenPrepare - This pass prepares a function for instruction selection.
 //
 FunctionPass *createCodeGenPreparePass(const TargetLowering *TLI = 0);