diff options
| -rw-r--r-- | src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp | 16 |
1 files changed, 7 insertions, 9 deletions
diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp b/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp index 92f9a156f7c..b3e1e69b016 100644 --- a/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp +++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp @@ -185,15 +185,13 @@ NVC0LegalizePostRA::findFirstUses( for (Value::UseIterator u = v->uses.begin(); u != v->uses.end(); ++u) { Instruction *usei = (*u)->getInsn(); - /* XXX HACK ALERT XXX - * - * This shouldn't have to be here, we should always be making forward - * progress by looking at the uses. However this somehow does not - * appear to be the case. Probably because this is being done right - * after RA, when the defs/uses lists have been messed with by node - * merging. This should probably be moved to being done right before - * RA. But this will do for now. - */ + // NOTE: In case of a loop that overwrites a value but never uses + // it, it can happen that we have a cycle of uses that consists only + // of phis and no-op moves and will thus cause an infinite loop here + // since these are not considered actual uses. + // The most obvious (and perhaps the only) way to prevent this is to + // remember which instructions we've already visited. + if (visited.find(usei) != visited.end()) continue; |