<html>
    <head>
      <base href="https://bugs.llvm.org/">
    </head>
    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - NVPTXInferAddressSpaces crashes when rewriting a bitcast instruction."
   href="https://bugs.llvm.org/show_bug.cgi?id=31948">31948</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>NVPTXInferAddressSpaces crashes when rewriting a bitcast instruction.
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>libraries
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>trunk
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>PC
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>Linux
          </td>
        </tr>

        <tr>
          <th>Status</th>
          <td>NEW
          </td>
        </tr>

        <tr>
          <th>Severity</th>
          <td>enhancement
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>P
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>Backend: PTX
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>unassignedbugs@nondot.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>acjacob@us.ibm.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>llvm-bugs@lists.llvm.org
          </td>
        </tr></table>
      <p>
        <div>
        <pre>I came across the issue when compiling an OpenMP program for the NVPTX target. 
I've written a simple testcase in CUDA that also exposes the crash.

---
typedef struct {
  float a;
  float *b;
} bar;

__device__ __shared__ bar var1;

__global__ void axpy(float a, float* x, float* y) {
    *(var1.b) += 1.0;
    int *p = (int *) &(var1.b);
    *p = 32;
}
---

Extract of traceback:

---
clang-5.0: llvm/lib/IR/Constants.cpp:1698: static llvm::Constant
*llvm::ConstantExpr::getBitCast(llvm::Constant *, llvm::Type *, bool):
Assertion `CastInst::castIsValid(Instruction::BitCast, C, DstTy) && "Invalid
constantexpr bitcast!"' failed.
...
#9 llvm::ConstantExpr::getBitCast(llvm::Constant*, llvm::Type*, bool)
llvm/lib/IR/Constants.cpp:1697:3
#10 cloneConstantExprWithNewAddressSpace(llvm::ConstantExpr*, unsigned int,
llvm::ValueMap<llvm::Value const*, llvm::WeakVH,
llvm::ValueMapConfig<llvm::Value const*, llvm::sys::SmartMutex<false> > >
const&) llvm/lib/Target/NVPTX/NVPTXInferAddressSpaces.cpp:347:12
#11 cloneValueWithNewAddressSpace(llvm::Value*, unsigned int,
llvm::ValueMap<llvm::Value const*, llvm::WeakVH,
llvm::ValueMapConfig<llvm::Value const*, llvm::sys::SmartMutex<false> > >
const&, llvm::SmallVectorImpl<llvm::Use const*>*)
llvm/lib/Target/NVPTX/NVPTXInferAddressSpaces.cpp:416:10
#12 (anonymous
namespace)::NVPTXInferAddressSpaces::rewriteWithNewAddressSpaces(std::vector<llvm::Value*,
std::allocator<llvm::Value*> > const&, llvm::DenseMap<llvm::Value const*,
unsigned int, llvm::DenseMapInfo<llvm::Value const*>,
llvm::detail::DenseMapPair<llvm::Value const*, unsigned int> > const&,
llvm::Function*) llvm/lib/Target/NVPTX/NVPTXInferAddressSpaces.cpp:536:34
#13 (anonymous
namespace)::NVPTXInferAddressSpaces::runOnFunction(llvm::Function&)
llvm/lib/Target/NVPTX/NVPTXInferAddressSpaces.cpp:450:10
#14 0x0000000011861dcc llvm::FPPassManager::runOnFunction(llvm::Function&)
llvm/lib/IR/LegacyPassManager.cpp:1513:27
---

A quick attempt to understand the code in this file and produce a patch
resulted in the following, but someone who understands the code better should
be able to determine the right fix.

Patch:

---
diff --git a/lib/Target/NVPTX/NVPTXInferAddressSpaces.cpp
b/lib/Target/NVPTX/NVPTXInferAddressSpaces.cpp
index 60c6d3d..a8451b0 100644
--- a/lib/Target/NVPTX/NVPTXInferAddressSpaces.cpp
+++ b/lib/Target/NVPTX/NVPTXInferAddressSpaces.cpp
@@ -343,6 +343,8 @@ static Value *cloneConstantExprWithNewAddressSpace(
     assert(CE->getOperand(0)->getType()->getPointerAddressSpace() ==
            NewAddrSpace);
     return ConstantExpr::getBitCast(CE->getOperand(0), TargetType);
+  } else if (CE->getOpcode() == Instruction::BitCast) {
+    return ConstantExpr::getAddrSpaceCast(CE->getOperand(0), TargetType);
   }

   // Computes the operands of the new constant expression.
---


Thanks,
Arpith</pre>
        </div>
      </p>


      <hr>
      <span>You are receiving this mail because:</span>

      <ul>
          <li>You are on the CC list for the bug.</li>
      </ul>
    </body>
</html>