[turbofan] Support unboxed float and double stack parameters and add tests.

src/compiler/ppc/instruction-selector-ppc.cc

Index: src/compiler/ppc/instruction-selector-ppc.cc
diff --git a/src/compiler/ppc/instruction-selector-ppc.cc b/src/compiler/ppc/instruction-selector-ppc.cc
index bff41c3609c89302baa8e32f8d1a4467ee866400..194b95f90ddf03159837f7728851df3cecdc5421 100644
--- a/src/compiler/ppc/instruction-selector-ppc.cc
+++ b/src/compiler/ppc/instruction-selector-ppc.cc
@@ -1474,14 +1474,16 @@ void InstructionSelector::VisitCall(Node* node, BasicBlock* handler) {
     }
   } else {
     // Push any stack arguments.
-    int num_slots = buffer.pushed_nodes.size();
+    int num_slots = static_cast<int>(descriptor->StackParameterCount());
     int slot = 0;
-    for (Node* node : buffer.pushed_nodes) {
+    for (Node* input : buffer.pushed_nodes) {
+      // Skip any alignment holes in pushed nodes.
+      if (input == nullptr) continue;
       if (slot == 0) {
-        Emit(kPPC_PushFrame, g.NoOutput(), g.UseRegister(node),
+        Emit(kPPC_PushFrame, g.NoOutput(), g.UseRegister(input),
              g.TempImmediate(num_slots));
       } else {
-        Emit(kPPC_StoreToStackSlot, g.NoOutput(), g.UseRegister(node),
+        Emit(kPPC_StoreToStackSlot, g.NoOutput(), g.UseRegister(input),
              g.TempImmediate(slot));
       }
       ++slot;
@@ -1578,8 +1580,9 @@ void InstructionSelector::VisitTailCall(Node* node) {
     InitializeCallBuffer(node, &buffer, true, false);
 
     // Push any stack arguments.
-    for (Node* node : base::Reversed(buffer.pushed_nodes)) {
-      Emit(kPPC_Push, g.NoOutput(), g.UseRegister(node));
+    for (Node* input : base::Reversed(buffer.pushed_nodes)) {
+      if (input == nullptr) continue;
+      Emit(kPPC_Push, g.NoOutput(), g.UseRegister(input));
     }
 
     // Select the appropriate opcode based on the call type.