Commit bfb77364 authored by Roger Ferrer Ibanez's avatar Roger Ferrer Ibanez
Browse files

[OpenMP] Fix accidental reuse of VLA size 

We were using an OpaqueValueExpr allocated on the stack to store
the size of a VLA. Because the VLASizeMap in CodegenFunction
uses the address of the expression to avoid recomputing VLAs,
we were accidentally reusing an earlier llvm::Value. This led to
invalid LLVM IR.

This is a temporary solution until VLASizeMap can be pushed and popped
based on the context.

Differential Revision: https://reviews.llvm.org/D107666
parent 62fe3dcf

clang/lib/CodeGen/CGOpenMPRuntime.cpp

+8 −8
Original line number Diff line number Diff line
@@ -4401,14 +4401,14 @@ CGOpenMPRuntime::emitTaskInit(CodeGenFunction &CGF, SourceLocation Loc, 
    if (NumOfElements) {

      NumOfElements = CGF.Builder.CreateNUWAdd(

          llvm::ConstantInt::get(CGF.SizeTy, NumAffinities), NumOfElements);

      OpaqueValueExpr OVE(

      auto *OVE = new (C) OpaqueValueExpr(

          Loc,

          C.getIntTypeForBitwidth(C.getTypeSize(C.getSizeType()), /*Signed=*/0),

          VK_PRValue);

      CodeGenFunction::OpaqueValueMapping OpaqueMap(CGF, &OVE,

      CodeGenFunction::OpaqueValueMapping OpaqueMap(CGF, OVE,

                                                    RValue::get(NumOfElements));

      KmpTaskAffinityInfoArrayTy =

          C.getVariableArrayType(KmpTaskAffinityInfoTy, &OVE, ArrayType::Normal,

          C.getVariableArrayType(KmpTaskAffinityInfoTy, OVE, ArrayType::Normal,

                                 /*IndexTypeQuals=*/0, SourceRange(Loc, Loc));

      // Properly emit variable-sized array.

      auto *PD = ImplicitParamDecl::Create(C, KmpTaskAffinityInfoArrayTy,
@@ -4899,13 +4899,13 @@ std::pair<llvm::Value *, Address> CGOpenMPRuntime::emitDependClause( 
      NumOfElements =

          CGF.Builder.CreateNUWAdd(NumOfRegularWithIterators, NumOfElements);

    }

    OpaqueValueExpr OVE(Loc,

                        C.getIntTypeForBitwidth(/*DestWidth=*/64, /*Signed=*/0),

    auto *OVE = new (C) OpaqueValueExpr(

        Loc, C.getIntTypeForBitwidth(/*DestWidth=*/64, /*Signed=*/0),

        VK_PRValue);

    CodeGenFunction::OpaqueValueMapping OpaqueMap(CGF, &OVE,

    CodeGenFunction::OpaqueValueMapping OpaqueMap(CGF, OVE,

                                                  RValue::get(NumOfElements));

    KmpDependInfoArrayTy =

        C.getVariableArrayType(KmpDependInfoTy, &OVE, ArrayType::Normal,

        C.getVariableArrayType(KmpDependInfoTy, OVE, ArrayType::Normal,

                               /*IndexTypeQuals=*/0, SourceRange(Loc, Loc));

    // CGF.EmitVariablyModifiedType(KmpDependInfoArrayTy);

    // Properly emit variable-sized array.

clang/test/OpenMP/vla_iterator_cache_bug.c

0 → 100644
+25 −0
Original line number Diff line number Diff line 
// RUN: %clang_cc1 -verify -fopenmp -x c++ -triple x86_64-unknown-linux-gnu \

// RUN:   -emit-llvm %s -o - | FileCheck %s



// expected-no-diagnostics



extern int bounds1(int);

extern int bounds2(int);



extern void fun2(int n, int *a, int *b);

extern void fun3(int n, int *a, int *b);



void fun1(int n, int *a, int *b)

{

#pragma omp task depend(iterator(j = 0 : bounds1(n)), in : a[b[j]])

  {

    fun2(n, a, b);

  }

// CHECK: alloca %struct.kmp_depend_info, i64 [[FIRST_VLA:%.*]], align 16



#pragma omp task depend(iterator(j = 0 : bounds2(n)), in : a[b[j]])

  {

    fun3(n, a, b);

  }

// CHECK-NOT: alloca %struct.kmp_depend_info, i64 [[FIRST_VLA]], align 16

}