Bug 1011745 - Correctly distinguish loop header phis. r=h4writer a=abillings

js/src/jit/MIRGraph.cpp

@@ -1141,7 +1141,7 @@ MBasicBlock::inheritPhis(MBasicBlock *header)
     for (size_t slot = 0; slot < stackDepth; slot++) {
         MDefinition *exitDef = getSlot(slot);
         MDefinition *loopDef = headerRp->getOperand(slot);
-        if (!loopDef->isPhi()) {
+        if (loopDef->block() != header) {
             MOZ_ASSERT(loopDef->block()->id() < header->id());
             MOZ_ASSERT(loopDef == exitDef);
             continue;
@@ -1177,7 +1177,7 @@ MBasicBlock::inheritPhisFromBackedge(MBasicBlock *backedge, bool *hadTypeChange)
 
         // Get the value of the loop header.
         MDefinition *loopDef = entryResumePoint()->getOperand(slot);
-        if (!loopDef->isPhi()) {
+        if (loopDef->block() != this) {
             // If we are finishing a pending loop header, then we need to ensure
             // that all operands are phis. This is usualy the case, except for
             // object/arrays build with generators, in which case we share the