[wasm] Use branch hint for the -1 check in I(32|64)Div.

src/compiler/wasm-compiler.cc

Index: src/compiler/wasm-compiler.cc
diff --git a/src/compiler/wasm-compiler.cc b/src/compiler/wasm-compiler.cc
index 4392896c644b8796b013903a81c22a5804f71e5b..5813bcb4ab285dbed1244f5bfa965abd0d0fe798 100644
--- a/src/compiler/wasm-compiler.cc
+++ b/src/compiler/wasm-compiler.cc
@@ -1796,11 +1796,13 @@ Node* WasmGraphBuilder::BuildI32DivS(Node* left, Node* right,
   MachineOperatorBuilder* m = jsgraph()->machine();
   trap_->ZeroCheck32(wasm::kTrapDivByZero, right, position);
   Node* before = *control_;
-  Node* denom_is_m1;
-  Node* denom_is_not_m1;
-  Branch(
-      graph()->NewNode(m->Word32Equal(), right, jsgraph()->Int32Constant(-1)),
-      &denom_is_m1, &denom_is_not_m1);
+  Node* is_denom_m1 =

[titzer, 2016/10/17 13:44:16]

Can you add a branch hint to the old method so that we don't need to break it
down to individual nodes here?

+      graph()->NewNode(m->Word32Equal(), right, jsgraph()->Int32Constant(-1));
+  Node* branch = graph()->NewNode(
+      jsgraph()->common()->Branch(BranchHint::kFalse), is_denom_m1, *control_);
+  Node* denom_is_m1 = graph()->NewNode(jsgraph()->common()->IfTrue(), branch);
+  Node* denom_is_not_m1 =
+      graph()->NewNode(jsgraph()->common()->IfFalse(), branch);
   *control_ = denom_is_m1;
   trap_->TrapIfEq32(wasm::kTrapDivUnrepresentable, left, kMinInt, position);
   if (*control_ != denom_is_m1) {
@@ -1931,18 +1933,21 @@ Node* WasmGraphBuilder::BuildI32AsmjsRemU(Node* left, Node* right) {
 
 Node* WasmGraphBuilder::BuildI64DivS(Node* left, Node* right,
                                      wasm::WasmCodePosition position) {
-  if (jsgraph()->machine()->Is32()) {
+  MachineOperatorBuilder* m = jsgraph()->machine();
+  if (m->Is32()) {
     return BuildDiv64Call(
         left, right, ExternalReference::wasm_int64_div(jsgraph()->isolate()),
         MachineType::Int64(), wasm::kTrapDivByZero, position);
   }
   trap_->ZeroCheck64(wasm::kTrapDivByZero, right, position);
   Node* before = *control_;
-  Node* denom_is_m1;
-  Node* denom_is_not_m1;
-  Branch(graph()->NewNode(jsgraph()->machine()->Word64Equal(), right,
-                          jsgraph()->Int64Constant(-1)),
-         &denom_is_m1, &denom_is_not_m1);
+  Node* is_denom_m1 =
+      graph()->NewNode(m->Word64Equal(), right, jsgraph()->Int64Constant(-1));
+  Node* branch = graph()->NewNode(
+      jsgraph()->common()->Branch(BranchHint::kFalse), is_denom_m1, *control_);
+  Node* denom_is_m1 = graph()->NewNode(jsgraph()->common()->IfTrue(), branch);
+  Node* denom_is_not_m1 =
+      graph()->NewNode(jsgraph()->common()->IfFalse(), branch);
   *control_ = denom_is_m1;
   trap_->TrapIfEq64(wasm::kTrapDivUnrepresentable, left,
                     std::numeric_limits<int64_t>::min(), position);