At top of generated isel SelectCode() is this:

if (!N.Val->hasOneUse()) {
    std::map<SDOperand, SDOperand>::iterator CGMI = CodeGenMap.find(N);
    if (CGMI != CodeGenMap.end()) return CGMI->second;
  }

Suppose a DAG like this:

           X
         ^   ^
        /     \
      USE1    USE2

Suppose USE1 is being selected first and during which X is selected and
returned a new node. After this, USE1 is no longer an use of X. During USE2
selection, X will be selected again since it has only one use!

The fix is to always query CodeGenMap.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@24679 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng 2005-12-12 23:22:48 +00:00
parent ac22c83e68
commit 481c8e0501

View File

@ -2234,10 +2234,8 @@ void DAGISelEmitter::EmitInstructionSelector(std::ostream &OS) {
<< " N.getOpcode() < (ISD::BUILTIN_OP_END+" << InstNS
<< "INSTRUCTION_LIST_END))\n"
<< " return N; // Already selected.\n\n"
<< " if (!N.Val->hasOneUse()) {\n"
<< " std::map<SDOperand, SDOperand>::iterator CGMI = CodeGenMap.find(N);\n"
<< " if (CGMI != CodeGenMap.end()) return CGMI->second;\n"
<< " }\n"
<< " std::map<SDOperand, SDOperand>::iterator CGMI = CodeGenMap.find(N);\n"
<< " if (CGMI != CodeGenMap.end()) return CGMI->second;\n"
<< " switch (N.getOpcode()) {\n"
<< " default: break;\n"
<< " case ISD::EntryToken: // These leaves remain the same.\n"