[llvm] r220997 - R600: Don't promote allocas when one of the users is a ptrtoint instruction

[Tom Stellard]

Author: tstellar
Date: Fri Oct 31 15:52:04 2014
New Revision: 220997

URL: http://llvm.org/viewvc/llvm-project?rev=220997&view=rev
Log:
R600: Don't promote allocas when one of the users is a ptrtoint instruction

We need to figure out how to track ptrtoint values all the
way until result is converted back to a pointer in order
to correctly rewrite the pointer type.

Modified:
    llvm/trunk/lib/Target/R600/AMDGPUPromoteAlloca.cpp
    llvm/trunk/test/CodeGen/R600/private-memory.ll

Modified: llvm/trunk/lib/Target/R600/AMDGPUPromoteAlloca.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/R600/AMDGPUPromoteAlloca.cpp?rev=220997&r1=220996&r2=220997&view=diff
==============================================================================
--- llvm/trunk/lib/Target/R600/AMDGPUPromoteAlloca.cpp (original)
+++ llvm/trunk/lib/Target/R600/AMDGPUPromoteAlloca.cpp Fri Oct 31 15:52:04 2014
@@ -234,7 +234,8 @@ static bool tryPromoteAllocaToVector(All
   return true;
 }
 
-static void collectUsesWithPtrTypes(Value *Val, std::vector<Value*> &WorkList) {
+static bool collectUsesWithPtrTypes(Value *Val, std::vector<Value*> &WorkList) {
+  bool Success = true;
   for (User *User : Val->users()) {
     if(std::find(WorkList.begin(), WorkList.end(), User) != WorkList.end())
       continue;
@@ -242,11 +243,20 @@ static void collectUsesWithPtrTypes(Valu
       WorkList.push_back(User);
       continue;
     }
+
+    // FIXME: Correctly handle ptrtoint instructions.
+    Instruction *UseInst = dyn_cast<Instruction>(User);
+    if (UseInst && UseInst->getOpcode() == Instruction::PtrToInt)
+      return false;
+
     if (!User->getType()->isPointerTy())
       continue;
+
     WorkList.push_back(User);
-    collectUsesWithPtrTypes(User, WorkList);
+
+    Success &= collectUsesWithPtrTypes(User, WorkList);
   }
+  return Success;
 }
 
 void AMDGPUPromoteAlloca::visitAlloca(AllocaInst &I) {
@@ -274,6 +284,13 @@ void AMDGPUPromoteAlloca::visitAlloca(Al
     return;
   }
 
+  std::vector<Value*> WorkList;
+
+  if (!collectUsesWithPtrTypes(&I, WorkList)) {
+    DEBUG(dbgs() << " Do not know how to convert all uses\n");
+    return;
+  }
+
   DEBUG(dbgs() << "Promoting alloca to local memory\n");
   LocalMemAvailable -= AllocaSize;
 
@@ -320,10 +337,6 @@ void AMDGPUPromoteAlloca::visitAlloca(Al
   I.replaceAllUsesWith(Offset);
   I.eraseFromParent();
 
-  std::vector<Value*> WorkList;
-
-  collectUsesWithPtrTypes(Offset, WorkList);
-
   for (std::vector<Value*>::iterator i = WorkList.begin(),
                                      e = WorkList.end(); i != e; ++i) {
     Value *V = *i;

Modified: llvm/trunk/test/CodeGen/R600/private-memory.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/R600/private-memory.ll?rev=220997&r1=220996&r2=220997&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/R600/private-memory.ll (original)
+++ llvm/trunk/test/CodeGen/R600/private-memory.ll Fri Oct 31 15:52:04 2014
@@ -290,3 +290,22 @@ entry:
   ret void
 }
 
+; AMDGPUPromoteAlloca does not know how to handle ptrtoint.  When it
+; finds one, it should stop trying to promote.
+
+; FUNC-LABEL: ptrtoint:
+; SI-NOT: DS_WRITE
+; SI: BUFFER_STORE_DWORD v{{[0-9]+}}, v{{[0-9]+}}, s[{{[0-9]+:[0-9]+}}], s{{[0-9]+}} offen
+; SI: BUFFER_LOAD_DWORD v{{[0-9]+}}, v{{[0-9]+}}, s[{{[0-9]+:[0-9]+}}], s{{[0-9]+}} offen offset:0x5
+define void @ptrtoint(i32 addrspace(1)* %out, i32 %a, i32 %b) {
+  %alloca = alloca [16 x i32]
+  %tmp0 = getelementptr [16 x i32]* %alloca, i32 0, i32 %a
+  store i32 5, i32* %tmp0
+  %tmp1 = ptrtoint [16 x i32]* %alloca to i32
+  %tmp2 = add i32 %tmp1, 5
+  %tmp3 = inttoptr i32 %tmp2 to i32*
+  %tmp4 = getelementptr i32* %tmp3, i32 %b
+  %tmp5 = load i32* %tmp4
+  store i32 %tmp5, i32 addrspace(1)* %out
+  ret void
+}