[PATCH] D130427: RegAllocGreedy: Avoid overflowing priority bitfields

[Jay Foad via Phabricator via llvm-commits]

foad added inline comments.


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Comment at: llvm/lib/CodeGen/RegAllocGreedy.cpp:332-333
+    // 30 Preference priority
+    // 29 Global bit
+    // 28-24 AllocPriority
+    // 0-23 Size/Instr distance
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These two get swapped by RegClassPriorityTrumpsGlobalness.


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Comment at: llvm/lib/Target/PowerPC/PPCRegisterInfoMMA.td:80
   // ACC registers.
-  let AllocationPriority = 36;
+  let AllocationPriority = 30;
+  let GlobalPriority = true;
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Shouldn't this be 36 - 32 = 4 to preserve current behaviour?


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Comment at: llvm/utils/TableGen/CodeGenRegisters.cpp:806
   int AllocationPriority = R->getValueAsInt("AllocationPriority");
-  if (AllocationPriority < 0 || AllocationPriority > 63)
-    PrintFatalError(R->getLoc(), "AllocationPriority out of range [0,63]");
+  if (AllocationPriority < 0 || !isUInt<5>(AllocationPriority))
+    PrintFatalError(R->getLoc(), "AllocationPriority out of range [0,31]");
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The `< 0` check seems redundant.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D130427/new/

https://reviews.llvm.org/D130427