PPC/s390: [arm] Match LoadStackPointer with comparison.

Port 5dfe23a4

Original Commit Message:

    When encountering a LoadStackPointer input to a comparison, generate a register
    LocationOperand that points to the stack pointer. This can avoid unnecessary
    spilling of the stack pointer.

R=georgia.kouveli@arm.com, joransiu@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=
LOG=N

Change-Id: Ie3fecf70f78c234fefad86fec74820a61f3d227b
Reviewed-on: https://chromium-review.googlesource.com/1057965Reviewed-by: Joran Siu <joransiu@ca.ibm.com>
Commit-Queue: Junliang Yan <jyan@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#53167}

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

@@ -66,6 +66,17 @@ class PPCOperandGenerator final : public OperandGenerator {
     }
     return false;
   }
+
+  // Use the stack pointer if the node is LoadStackPointer, otherwise assign a
+  // register.
+  InstructionOperand UseRegisterOrStackPointer(Node* node) {
+    if (node->opcode() == IrOpcode::kLoadStackPointer) {
+      return LocationOperand(LocationOperand::EXPLICIT,
+                             LocationOperand::REGISTER,
+                             MachineRepresentation::kWord32, sp.code());
+    }
+    return UseRegister(node);
+  }
 };
 
 
@@ -1483,15 +1494,15 @@ void VisitWordCompare(InstructionSelector* selector, Node* node,
 
   // Match immediates on left or right side of comparison.
   if (g.CanBeImmediate(right, immediate_mode)) {
-    VisitCompare(selector, opcode, g.UseRegister(left), g.UseImmediate(right),
-                 cont);
+    VisitCompare(selector, opcode, g.UseRegisterOrStackPointer(left),
+                 g.UseImmediate(right), cont);
   } else if (g.CanBeImmediate(left, immediate_mode)) {
     if (!commutative) cont->Commute();
-    VisitCompare(selector, opcode, g.UseRegister(right), g.UseImmediate(left),
-                 cont);
+    VisitCompare(selector, opcode, g.UseRegisterOrStackPointer(right),
+                 g.UseImmediate(left), cont);
   } else {
-    VisitCompare(selector, opcode, g.UseRegister(left), g.UseRegister(right),
-                 cont);
+    VisitCompare(selector, opcode, g.UseRegisterOrStackPointer(left),
+                 g.UseRegisterOrStackPointer(right), cont);
   }
 }
 

src/compiler/s390/instruction-selector-s390.cc

@@ -243,6 +243,17 @@ class S390OperandGenerator final : public OperandGenerator {
   bool Is64BitOperand(Node* node) {
     return MachineRepresentation::kWord64 == GetRepresentation(node);
   }
+
+  // Use the stack pointer if the node is LoadStackPointer, otherwise assign a
+  // register.
+  InstructionOperand UseRegisterOrStackPointer(Node* node) {
+    if (node->opcode() == IrOpcode::kLoadStackPointer) {
+      return LocationOperand(LocationOperand::EXPLICIT,
+                             LocationOperand::REGISTER,
+                             MachineRepresentation::kWord32, sp.code());
+    }
+    return UseRegister(node);
+  }
 };
 
 namespace {
@@ -1662,7 +1673,7 @@ void VisitWordCompare(InstructionSelector* selector, Node* node,
     return VisitLoadAndTest(selector, load_and_test, node, left, cont, true);
   }
 
-  inputs[input_count++] = g.UseRegister(left);
+  inputs[input_count++] = g.UseRegisterOrStackPointer(left);
   if (g.CanBeMemoryOperand(opcode, node, right, effect_level)) {
     // generate memory operand
     AddressingMode addressing_mode = g.GetEffectiveAddressMemoryOperand(