[PATCH] D17939: AMDGPU: Don't use InstVisitor for AMDGPUPromoteAlloca

[Matt Arsenault via llvm-commits]

arsenm created this revision.
arsenm added a reviewer: tstellarAMD.
arsenm added a subscriber: llvm-commits.
Herald added a subscriber: arsenm.

Frontend authors are strongly encouraged to keep allocas
in the entry block, so don't bother visiting every instruction
in the other blocks of the function.

http://reviews.llvm.org/D17939

Files:
  lib/Target/AMDGPU/AMDGPUPromoteAlloca.cpp

Index: lib/Target/AMDGPU/AMDGPUPromoteAlloca.cpp
===================================================================
--- lib/Target/AMDGPU/AMDGPUPromoteAlloca.cpp
+++ lib/Target/AMDGPU/AMDGPUPromoteAlloca.cpp
@@ -16,7 +16,7 @@
 #include "AMDGPUSubtarget.h"
 #include "llvm/Analysis/ValueTracking.h"
 #include "llvm/IR/IRBuilder.h"
-#include "llvm/IR/InstVisitor.h"
+#include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/MDBuilder.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
@@ -28,8 +28,7 @@
 namespace {
 
 // FIXME: This can create globals so should be a module pass.
-class AMDGPUPromoteAlloca : public FunctionPass,
-                            public InstVisitor<AMDGPUPromoteAlloca> {
+class AMDGPUPromoteAlloca : public FunctionPass {
 private:
   const TargetMachine *TM;
   Module *Mod;
@@ -63,7 +62,7 @@
     return "AMDGPU Promote Alloca";
   }
 
-  void visitAlloca(AllocaInst &I);
+  void handleAlloca(AllocaInst &I);
 };
 
 } // End anonymous namespace
@@ -140,7 +139,14 @@
   LocalMemAvailable = std::max(0, LocalMemAvailable);
   DEBUG(dbgs() << LocalMemAvailable << " bytes free in local memory.\n");
 
-  visit(F);
+  BasicBlock &EntryBB = *F.begin();
+  for (auto I = EntryBB.begin(), E = EntryBB.end(); I != E; ) {
+    AllocaInst *AI = dyn_cast<AllocaInst>(I);
+
+    ++I;
+    if (AI)
+      handleAlloca(*AI);
+  }
 
   return true;
 }
@@ -461,7 +467,7 @@
   return true;
 }
 
-void AMDGPUPromoteAlloca::visitAlloca(AllocaInst &I) {
+void AMDGPUPromoteAlloca::handleAlloca(AllocaInst &I) {
   if (!I.isStaticAlloca())
     return;
 


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