[llvm-commits] [parallel] CVS: llvm/lib/Transforms/Parallel/LowerParaBr.cpp

[Misha Brukman]

Changes in directory llvm/lib/Transforms/Parallel:

LowerParaBr.cpp updated: 1.1.2.1 -> 1.1.2.2

---
Log message:

llvm.join no longer necessarily uses pbr directly, plus there could be >1 join
for every pbr, so we need to remove them all in a given parallel region.


---
Diffs of the changes:  (+38 -15)

Index: llvm/lib/Transforms/Parallel/LowerParaBr.cpp
diff -u llvm/lib/Transforms/Parallel/LowerParaBr.cpp:1.1.2.1 llvm/lib/Transforms/Parallel/LowerParaBr.cpp:1.1.2.2
--- llvm/lib/Transforms/Parallel/LowerParaBr.cpp:1.1.2.1	Sat Apr 17 19:45:51 2004
+++ llvm/lib/Transforms/Parallel/LowerParaBr.cpp	Fri May  7 16:37:09 2004
@@ -43,6 +43,7 @@
 
   private:
     void straightenSequence(ParallelSeq *PS);
+    Function* getJoinIntrinsic(Module *M);    
   };
 
   RegisterOpt<LowerParaBr> X("lowerpbr", "Lower pbr to sequential code");
@@ -66,6 +67,10 @@
   return Changed;
 }
 
+static bool contains(std::vector<BasicBlock*> haystack, BasicBlock *needle) {
+  return std::find(haystack.begin(), haystack.end(), needle) != haystack.end();
+}
+
 /// straightenSequence - Recursively process parallel sequences
 ///
 void LowerParaBr::straightenSequence(ParallelSeq *PS) {
@@ -79,27 +84,45 @@
          ci != ce; ++ci) 
       straightenSequence(*ci);
 
-    // Stitch previous region to the current one by rewriting the last branch
+    // Stitch previous region to the current one by all branches to the join
+    // block instead branch to the first block of the second region
     if (PrevPR) {
-      std::vector<BasicBlock*> &PrevBlocks = PrevPR->getBlocks(),
+      std::vector<BasicBlock*> &PrevJoinBlocks = PrevPR->getJoinBlocks(),
         &PRBlocks = PR->getBlocks();
-      BasicBlock *PrevLastBB = PrevBlocks.back(), *PRFirstBB = PRBlocks[0];
-      TerminatorInst *TI = PrevLastBB->getTerminator();
-      new BranchInst(PRFirstBB, TI);
-      PrevLastBB->getInstList().erase(TI);
+      BasicBlock *PRFirstBB = PRBlocks[0];
+      for (std::vector<BasicBlock*>::iterator j = PrevJoinBlocks.begin(),
+             je = PrevJoinBlocks.end(); j != je; ++j) {
+        std::vector<User*> JUsers((*j)->use_begin(), (*j)->use_end());
+        for (std::vector<User*>::iterator u = JUsers.begin(), ue = JUsers.end();
+             u != ue; ++u)
+          if (Instruction *I = dyn_cast<Instruction>(*u))
+            if (contains(PR->getBlocks(), I->getParent()))
+              I->replaceUsesOfWith(*j, PRFirstBB);
+      }
     }
   }
 
-  // Remove the call to llvm.join()
-  ParaBrInst *pbr = dyn_cast<ParaBrInst>(PS->getHeader()->getTerminator());
-  assert(pbr && "pbr not a terminator of ParallelSeq header!");
-  std::vector<User*> Users(pbr->use_begin(), pbr->use_end());
+  Module *M = PS->getHeader()->getParent()->getParent();
+  Function *JoinIntr = getJoinIntrinsic(M);
+  std::vector<User*> Users(JoinIntr->use_begin(), JoinIntr->use_end());
+  // Remove the calls to llvm.join()
   for (std::vector<User*>::iterator use = Users.begin(), ue = Users.end();
        use != ue; ++use)
-    if (Instruction *Inst = dyn_cast<Instruction>(*use))
-      Inst->getParent()->getInstList().erase(Inst);
+    if (CallInst *CI = dyn_cast<CallInst>(*use))
+      if (contains(PR->getJoinBlocks(), CI->getParent()) || 
+          contains(PrevPR->getJoinBlocks(), CI->getParent()))
+        CI->getParent()->getInstList().erase(CI);
+          
+  // Remove pbr
+  ParaBrInst *pbr = dyn_cast<ParaBrInst>(PS->getHeader()->getTerminator());
+  //assert(pbr && "Terminator of ParaSeq header is not a pbr");
+  if (pbr) {
+    new BranchInst(pbr->getSuccessor(0), pbr);
+    pbr->getParent()->getInstList().erase(pbr);
+  }
+}
 
-  // Rewrite pbr as a regular branch
-  new BranchInst(pbr->getSuccessor(0), pbr);
-  pbr->getParent()->getInstList().erase(pbr);
+Function* LowerParaBr::getJoinIntrinsic(Module *M) {
+  return M->getOrInsertFunction("llvm.join", Type::VoidTy,
+                                PointerType::get(Type::SByteTy), 0);
 }