[llvm] a9a1950 - Revert "[SCCP] Remove legacy SCCP pass."

[Florian Hahn via llvm-commits]

Author: Florian Hahn
Date: 2023-02-18T18:01:37Z
New Revision: a9a1950115d7db95c7439128b14af2cefe8f796d

URL: https://github.com/llvm/llvm-project/commit/a9a1950115d7db95c7439128b14af2cefe8f796d
DIFF: https://github.com/llvm/llvm-project/commit/a9a1950115d7db95c7439128b14af2cefe8f796d.diff

LOG: Revert "[SCCP] Remove legacy SCCP pass."

This reverts commit 5356fefc19df3fbf32d180b1b10e6226e8743541.

It looks like Polly still relies on the legacy SCCP pass. Bring it back
until the best way forward is determined.

Added: 
    

Modified: 
    llvm/include/llvm-c/Transforms/Scalar.h
    llvm/include/llvm/LinkAllPasses.h
    llvm/include/llvm/Transforms/Scalar.h
    llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
    llvm/lib/Transforms/Scalar/SCCP.cpp
    llvm/lib/Transforms/Scalar/Scalar.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/include/llvm-c/Transforms/Scalar.h b/llvm/include/llvm-c/Transforms/Scalar.h
index 06f20e5eaaa4f..5aaeb9470168f 100644
--- a/llvm/include/llvm-c/Transforms/Scalar.h
+++ b/llvm/include/llvm-c/Transforms/Scalar.h
@@ -97,6 +97,9 @@ void LLVMAddPartiallyInlineLibCallsPass(LLVMPassManagerRef PM);
 /** See llvm::createReassociatePass function. */
 void LLVMAddReassociatePass(LLVMPassManagerRef PM);
 
+/** See llvm::createSCCPPass function. */
+void LLVMAddSCCPPass(LLVMPassManagerRef PM);
+
 /** See llvm::createSROAPass function. */
 void LLVMAddScalarReplAggregatesPass(LLVMPassManagerRef PM);
 

diff  --git a/llvm/include/llvm/LinkAllPasses.h b/llvm/include/llvm/LinkAllPasses.h
index 45a9f47254336..8d1d1883972a2 100644
--- a/llvm/include/llvm/LinkAllPasses.h
+++ b/llvm/include/llvm/LinkAllPasses.h
@@ -135,6 +135,7 @@ namespace {
       (void) llvm::createRegionOnlyViewerPass();
       (void) llvm::createRegionPrinterPass();
       (void) llvm::createRegionViewerPass();
+      (void) llvm::createSCCPPass();
       (void) llvm::createSafeStackPass();
       (void) llvm::createSROAPass();
       (void) llvm::createSingleLoopExtractorPass();

diff  --git a/llvm/include/llvm/Transforms/Scalar.h b/llvm/include/llvm/Transforms/Scalar.h
index 1845084d6e51a..2dea75291d4c7 100644
--- a/llvm/include/llvm/Transforms/Scalar.h
+++ b/llvm/include/llvm/Transforms/Scalar.h
@@ -31,6 +31,12 @@ class Pass;
 //
 FunctionPass *createAlignmentFromAssumptionsPass();
 
+//===----------------------------------------------------------------------===//
+//
+// SCCP - Sparse conditional constant propagation.
+//
+FunctionPass *createSCCPPass();
+
 //===----------------------------------------------------------------------===//
 //
 // RedundantDbgInstElimination - This pass removes redundant dbg intrinsics

diff  --git a/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp b/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
index 894fc90cef1b6..841e608079018 100644
--- a/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
+++ b/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
@@ -167,6 +167,7 @@ void PassManagerBuilder::addFunctionSimplificationPasses(
     MPM.add(createMergedLoadStoreMotionPass()); // Merge ld/st in diamonds
     MPM.add(createGVNPass(DisableGVNLoadPRE));  // Remove redundancies
   }
+  MPM.add(createSCCPPass());                  // Constant prop with SCCP
 
   // Delete dead bit computations (instcombine runs after to fold away the dead
   // computations, and then ADCE will run later to exploit any new DCE
@@ -235,6 +236,7 @@ void PassManagerBuilder::addVectorPasses(legacy::PassManagerBase &PM,
                                          .sinkCommonInsts(true)));
 
   if (IsFullLTO) {
+    PM.add(createSCCPPass());                 // Propagate exposed constants
     PM.add(createInstructionCombiningPass()); // Clean up again
     PM.add(createBitTrackingDCEPass());
   }

diff  --git a/llvm/lib/Transforms/Scalar/SCCP.cpp b/llvm/lib/Transforms/Scalar/SCCP.cpp
index fcdc503c54a42..7b396c6ee0746 100644
--- a/llvm/lib/Transforms/Scalar/SCCP.cpp
+++ b/llvm/lib/Transforms/Scalar/SCCP.cpp
@@ -41,6 +41,7 @@
 #include "llvm/IR/Type.h"
 #include "llvm/IR/User.h"
 #include "llvm/IR/Value.h"
+#include "llvm/InitializePasses.h"
 #include "llvm/Pass.h"
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/Debug.h"
@@ -135,3 +136,54 @@ PreservedAnalyses SCCPPass::run(Function &F, FunctionAnalysisManager &AM) {
   PA.preserve<DominatorTreeAnalysis>();
   return PA;
 }
+
+namespace {
+
+//===--------------------------------------------------------------------===//
+//
+/// SCCP Class - This class uses the SCCPSolver to implement a per-function
+/// Sparse Conditional Constant Propagator.
+///
+class SCCPLegacyPass : public FunctionPass {
+public:
+  // Pass identification, replacement for typeid
+  static char ID;
+
+  SCCPLegacyPass() : FunctionPass(ID) {
+    initializeSCCPLegacyPassPass(*PassRegistry::getPassRegistry());
+  }
+
+  void getAnalysisUsage(AnalysisUsage &AU) const override {
+    AU.addRequired<TargetLibraryInfoWrapperPass>();
+    AU.addPreserved<GlobalsAAWrapperPass>();
+    AU.addPreserved<DominatorTreeWrapperPass>();
+  }
+
+  // runOnFunction - Run the Sparse Conditional Constant Propagation
+  // algorithm, and return true if the function was modified.
+  bool runOnFunction(Function &F) override {
+    if (skipFunction(F))
+      return false;
+    const DataLayout &DL = F.getParent()->getDataLayout();
+    const TargetLibraryInfo *TLI =
+        &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(F);
+    auto *DTWP = getAnalysisIfAvailable<DominatorTreeWrapperPass>();
+    DomTreeUpdater DTU(DTWP ? &DTWP->getDomTree() : nullptr,
+                       DomTreeUpdater::UpdateStrategy::Lazy);
+    return runSCCP(F, DL, TLI, DTU);
+  }
+};
+
+} // end anonymous namespace
+
+char SCCPLegacyPass::ID = 0;
+
+INITIALIZE_PASS_BEGIN(SCCPLegacyPass, "sccp",
+                      "Sparse Conditional Constant Propagation", false, false)
+INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
+INITIALIZE_PASS_END(SCCPLegacyPass, "sccp",
+                    "Sparse Conditional Constant Propagation", false, false)
+
+// createSCCPPass - This is the public interface to this file.
+FunctionPass *llvm::createSCCPPass() { return new SCCPLegacyPass(); }
+

diff  --git a/llvm/lib/Transforms/Scalar/Scalar.cpp b/llvm/lib/Transforms/Scalar/Scalar.cpp
index b59f333360eb0..e07471f75dae2 100644
--- a/llvm/lib/Transforms/Scalar/Scalar.cpp
+++ b/llvm/lib/Transforms/Scalar/Scalar.cpp
@@ -83,6 +83,7 @@ void llvm::initializeScalarOpts(PassRegistry &Registry) {
   initializeRegToMemLegacyPass(Registry);
   initializeRewriteStatepointsForGCLegacyPassPass(Registry);
   initializeScalarizeMaskedMemIntrinLegacyPassPass(Registry);
+  initializeSCCPLegacyPassPass(Registry);
   initializeSROALegacyPassPass(Registry);
   initializeCFGSimplifyPassPass(Registry);
   initializeStructurizeCFGLegacyPassPass(Registry);
@@ -195,6 +196,10 @@ void LLVMAddReassociatePass(LLVMPassManagerRef PM) {
   unwrap(PM)->add(createReassociatePass());
 }
 
+void LLVMAddSCCPPass(LLVMPassManagerRef PM) {
+  unwrap(PM)->add(createSCCPPass());
+}
+
 void LLVMAddScalarReplAggregatesPass(LLVMPassManagerRef PM) {
   unwrap(PM)->add(createSROAPass());
 }