Support inlining and crankshaft optimization of Math.random.

src/ia32/lithium-codegen-ia32.cc

Index: src/ia32/lithium-codegen-ia32.cc
diff --git a/src/ia32/lithium-codegen-ia32.cc b/src/ia32/lithium-codegen-ia32.cc
index 9940f8af7be54fc72e96af0939b4faa6350135d6..537c55895de2dbb03eeb1b4ddfbf6b246bc68251 100644
--- a/src/ia32/lithium-codegen-ia32.cc
+++ b/src/ia32/lithium-codegen-ia32.cc
@@ -3014,6 +3014,29 @@ void LCodeGen::DoPower(LPower* instr) {
 }
 
 
+void LCodeGen::DoRandom(LRandom* instr) {
+  // Having marked this instruction as a call we can use any
+  // registers.
+  ASSERT(ToDoubleRegister(instr->result()).is(xmm1));
+  ASSERT(ToRegister(instr->InputAt(0)).is(eax));
+
+  __ PrepareCallCFunction(1, ebx);
+  __ mov(eax, FieldOperand(eax, GlobalObject::kGlobalContextOffset));
+  __ mov(Operand(esp, 0), eax);
+  __ CallCFunction(ExternalReference::random_uint32_function(isolate()), 1);
+
+  // Convert 32 random bits in eax to 0.(32 random bits) in a double
+  // by computing:
+  // ( 1.(20 0s)(32 random bits) x 2^20 ) - (1.0 x 2^20)).
+  __ mov(ebx, Immediate(0x49800000));  // 1.0 x 2^20 as single.
+  __ movd(xmm2, ebx);
+  __ movd(xmm1, eax);
+  __ cvtss2sd(xmm2, xmm2);
+  __ xorps(xmm1, xmm2);
+  __ subsd(xmm1, xmm2);
+}
+
+
 void LCodeGen::DoMathLog(LUnaryMathOperation* instr) {
   ASSERT(instr->value()->Equals(instr->result()));
   XMMRegister input_reg = ToDoubleRegister(instr->value());