[llvm-commits] CVS: llvm/utils/TableGen/DAGISelEmitter.cpp

[Evan Cheng]

Changes in directory llvm/utils/TableGen:

DAGISelEmitter.cpp updated: 1.95 -> 1.96
---
Log message:

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.


---
Diffs of the changes:  (+2 -4)

 DAGISelEmitter.cpp |    6 ++----
 1 files changed, 2 insertions(+), 4 deletions(-)


Index: llvm/utils/TableGen/DAGISelEmitter.cpp
diff -u llvm/utils/TableGen/DAGISelEmitter.cpp:1.95 llvm/utils/TableGen/DAGISelEmitter.cpp:1.96
--- llvm/utils/TableGen/DAGISelEmitter.cpp:1.95	Mon Dec 12 13:37:43 2005
+++ llvm/utils/TableGen/DAGISelEmitter.cpp	Mon Dec 12 17:22:48 2005
@@ -2234,10 +2234,8 @@
      << "      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"