[polly] r219005 - Put the parallel context alloca into the function entry block.

[Johannes Doerfert]

Author: jdoerfert
Date: Fri Oct  3 14:12:05 2014
New Revision: 219005

URL: http://llvm.org/viewvc/llvm-project?rev=219005&view=rev
Log:
Put the parallel context alloca into the function entry block.

  We use lifetime markers to limit the actual life range (similar to clang).

Differential Revision: http://reviews.llvm.org/D5582


Added:
    polly/trunk/test/Cloog/CodeGen/OpenMP/lifetime_markers.ll
Modified:
    polly/trunk/lib/CodeGen/LoopGenerators.cpp

Modified: polly/trunk/lib/CodeGen/LoopGenerators.cpp
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/lib/CodeGen/LoopGenerators.cpp?rev=219005&r1=219004&r2=219005&view=diff
==============================================================================
--- polly/trunk/lib/CodeGen/LoopGenerators.cpp (original)
+++ polly/trunk/lib/CodeGen/LoopGenerators.cpp Fri Oct  3 14:12:05 2014
@@ -168,6 +168,11 @@ Value *ParallelLoopGenerator::createPara
   Builder.CreateCall(SubFn, SubFnParam);
   createCallJoinThreads();
 
+  // Mark the end of the lifetime for the parameter struct.
+  Type *Ty = Struct->getType();
+  ConstantInt *SizeOf = Builder.getInt64(DL.getTypeAllocSize(Ty));
+  Builder.CreateLifetimeEnd(Struct, SizeOf);
+
   return IV;
 }
 
@@ -273,9 +278,17 @@ ParallelLoopGenerator::storeValuesIntoSt
   for (Value *V : Values)
     Members.push_back(V->getType());
 
+  // We do not want to allocate the alloca inside any loop, thus we allocate it
+  // in the entry block of the function and use annotations to denote the actual
+  // live span (similar to clang).
+  BasicBlock &EntryBB = Builder.GetInsertBlock()->getParent()->getEntryBlock();
+  Instruction *IP = EntryBB.getFirstInsertionPt();
   StructType *Ty = StructType::get(Builder.getContext(), Members);
-  Value *Struct =
-      new AllocaInst(Ty, 0, "polly.par.userContext", Builder.GetInsertPoint());
+  Value *Struct = new AllocaInst(Ty, 0, "polly.par.userContext", IP);
+
+  // Mark the start of the lifetime for the parameter struct.
+  ConstantInt *SizeOf = Builder.getInt64(DL.getTypeAllocSize(Ty));
+  Builder.CreateLifetimeStart(Struct, SizeOf);
 
   for (unsigned i = 0; i < Values.size(); i++) {
     Value *Address = Builder.CreateStructGEP(Struct, i);

Added: polly/trunk/test/Cloog/CodeGen/OpenMP/lifetime_markers.ll
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/test/Cloog/CodeGen/OpenMP/lifetime_markers.ll?rev=219005&view=auto
==============================================================================
--- polly/trunk/test/Cloog/CodeGen/OpenMP/lifetime_markers.ll (added)
+++ polly/trunk/test/Cloog/CodeGen/OpenMP/lifetime_markers.ll Fri Oct  3 14:12:05 2014
@@ -0,0 +1,65 @@
+; RUN: opt %loadPolly -S -polly-codegen -enable-polly-openmp < %s | FileCheck %s
+;
+; Check that we allocate the parallel context in the entry block and use
+; lifetime markers to mark the live range.
+;
+; CHECK: entry:
+; CHECK:   %polly.par.userContext = alloca { i32* }
+; CHECK:   br label %while.cond
+;
+; CHECK:       polly.start:
+; CHECK-NEXT:    %[[BC1:[._0-9a-zA-Z]*]] = bitcast { i32* }* %polly.par.userContext to i8*
+; CHECK-NEXT:    call void @llvm.lifetime.start(i64 8, i8* %[[BC1]])
+; CHECK-NEXT:    %[[GEP:[._0-9a-zA-Z]*]] = getelementptr inbounds { i32* }* %polly.par.userContext, i32 0, i32 0
+; CHECK-NEXT:    store i32* %A, i32** %[[GEP]]
+; CHECK-NEXT:    %polly.par.userContext{{[0-9]*}} = bitcast { i32* }* %polly.par.userContext to i8*
+; CHECK-NEXT:    call void @GOMP_parallel_loop_runtime_start(void (i8*)* @jd.polly.subfn, i8* %polly.par.userContext{{[0-9]*}}, i64 0, i64 0, i64 1024, i64 1)
+; CHECK-NEXT:    call void @jd.polly.subfn(i8* %polly.par.userContext{{[0-9]*}})
+; CHECK-NEXT:    call void @GOMP_parallel_end()
+; CHECK-NEXT:    %[[BC2:[._0-9a-zA-Z]*]] = bitcast { i32* }* %polly.par.userContext to i8*
+; CHECK-NEXT:    call void @llvm.lifetime.end(i64 8, i8* %[[BC2]])
+; CHECK-NEXT:    br label %polly.merge_new_and_old
+
+;    int cond();
+;    void jd(int *A) {
+;      while (cond())
+;        for (int j = 0; j < 1024; j++)
+;          A[j] = 1;
+;    }
+;
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+
+define void @jd(i32* %A) {
+entry:
+  br label %while.cond
+
+while.cond:                                       ; preds = %for.end, %entry
+  %call = call i32 (...)* @cond() #2
+  %tobool = icmp eq i32 %call, 0
+  br i1 %tobool, label %while.end, label %while.body
+
+while.body:                                       ; preds = %while.cond
+  br label %for.cond
+
+for.cond:                                         ; preds = %for.inc, %while.body
+  %indvars.iv = phi i64 [ %indvars.iv.next, %for.inc ], [ 0, %while.body ]
+  %exitcond = icmp ne i64 %indvars.iv, 1024
+  br i1 %exitcond, label %for.body, label %for.end
+
+for.body:                                         ; preds = %for.cond
+  %arrayidx = getelementptr inbounds i32* %A, i64 %indvars.iv
+  store i32 1, i32* %arrayidx, align 4
+  br label %for.inc
+
+for.inc:                                          ; preds = %for.body
+  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+  br label %for.cond
+
+for.end:                                          ; preds = %for.cond
+  br label %while.cond
+
+while.end:                                        ; preds = %while.cond
+  ret void
+}
+
+declare i32 @cond(...) #1