Implement a variation of scalar replacement for non-escaping allocations.

runtime/vm/stub_code_ia32.cc

Index: runtime/vm/stub_code_ia32.cc
diff --git a/runtime/vm/stub_code_ia32.cc b/runtime/vm/stub_code_ia32.cc
index 0af074b644cb7a07043a458992a8cf761619ddcc..cde7e0f22960ffb572cdc5eea1c36366bfdfd50f 100644
--- a/runtime/vm/stub_code_ia32.cc
+++ b/runtime/vm/stub_code_ia32.cc
@@ -394,11 +394,20 @@ static void GenerateDeoptimizationSequence(Assembler* assembler,
   if (preserve_eax) {
     __ pushl(EBX);  // Preserve result, it will be GC-d here.
   }
-  __ CallRuntime(kDeoptimizeMaterializeDoublesRuntimeEntry);
+  __ pushl(Immediate(Smi::RawValue(0)));  // Space for the result.
+  __ CallRuntime(kDeoptimizeMaterializeRuntimeEntry);
+  // Result tells stub how many bytes to remove from the expression stack
+  // of the bottom-most frame. They were used as materialization arguments.
+  __ popl(EBX);
+  __ SmiUntag(EBX);
   if (preserve_eax) {
     __ popl(EAX);  // Restore result.
   }
   __ LeaveFrame();
+
+  __ popl(ECX);  // Pop return address.
+  __ addl(ESP, EBX);  // Remove materialization arguments.
+  __ pushl(ECX);  // Push return address.
   __ ret();
 }