Bug 1642680: Share LRandom lowering code. r=jandem

The previous code was using a fixed result register, because bug 774364 was
using an OOL-path for `Math.random`, which was later removed in bug 322529.

Differential Revision: https://phabricator.services.mozilla.com/D77836

js/src/jit/CodeGenerator.cpp

@@ -14031,13 +14031,8 @@ void CodeGenerator::visitRandom(LRandom* ins) {
   FloatRegister output = ToFloatRegister(ins->output());
   Register rngReg = ToRegister(ins->temp0());
 
-#ifdef JS_PUNBOX64
-  Register64 temp1(ToRegister(ins->temp1()));
-  Register64 temp2(ToRegister(ins->temp2()));
-#else
-  Register64 temp1(ToRegister(ins->temp1()), ToRegister(ins->temp2()));
-  Register64 temp2(ToRegister(ins->temp3()), ToRegister(ins->temp4()));
-#endif
+  Register64 temp1 = ToRegister64(ins->temp1());
+  Register64 temp2 = ToRegister64(ins->temp2());
 
   const XorShift128PlusRNG* rng = gen->realm->addressOfRandomNumberGenerator();
   masm.movePtr(ImmPtr(rng), rngReg);

js/src/jit/Lowering.cpp

@@ -1595,6 +1595,11 @@ void LIRGenerator::visitMathFunction(MMathFunction* ins) {
   defineReturn(lir, ins);
 }
 
+void LIRGenerator::visitRandom(MRandom* ins) {
+  auto* lir = new (alloc()) LRandom(temp(), tempInt64(), tempInt64());
+  define(lir, ins);
+}
+
 // Try to mark an add or sub instruction as able to recover its input when
 // bailing out.
 template <typename S, typename T>

js/src/jit/arm/Lowering-arm.cpp

@@ -934,11 +934,6 @@ void LIRGenerator::visitSubstr(MSubstr* ins) {
   assignSafepoint(lir, ins);
 }
 
-void LIRGenerator::visitRandom(MRandom* ins) {
-  LRandom* lir = new (alloc()) LRandom(temp(), temp(), temp(), temp(), temp());
-  defineFixed(lir, ins, LFloatReg(ReturnDoubleReg));
-}
-
 void LIRGenerator::visitWasmTruncateToInt64(MWasmTruncateToInt64* ins) {
   MDefinition* opd = ins->input();
   MOZ_ASSERT(opd->type() == MIRType::Double || opd->type() == MIRType::Float32);

js/src/jit/arm64/Lowering-arm64.cpp

@@ -505,11 +505,6 @@ void LIRGenerator::visitSubstr(MSubstr* ins) {
   assignSafepoint(lir, ins);
 }
 
-void LIRGenerator::visitRandom(MRandom* ins) {
-  LRandom* lir = new (alloc()) LRandom(temp(), temp(), temp());
-  defineFixed(lir, ins, LFloatReg(ReturnDoubleReg));
-}
-
 void LIRGenerator::visitWasmTruncateToInt64(MWasmTruncateToInt64* ins) {
   MOZ_CRASH("NYI");
 }

js/src/jit/mips32/Lowering-mips32.cpp

@@ -218,11 +218,6 @@ void LIRGeneratorMIPS::lowerUModI64(MMod* mod) {
   defineReturn(lir, mod);
 }
 
-void LIRGenerator::visitRandom(MRandom* ins) {
-  LRandom* lir = new (alloc()) LRandom(temp(), temp(), temp(), temp(), temp());
-  defineFixed(lir, ins, LFloatReg(ReturnDoubleReg));
-}
-
 void LIRGenerator::visitWasmTruncateToInt64(MWasmTruncateToInt64* ins) {
   MDefinition* opd = ins->input();
   MOZ_ASSERT(opd->type() == MIRType::Double || opd->type() == MIRType::Float32);

js/src/jit/mips64/Lowering-mips64.cpp

@@ -146,11 +146,6 @@ void LIRGeneratorMIPS64::lowerTruncateFToInt32(MTruncateToInt32* ins) {
   define(new (alloc()) LTruncateFToInt32(useRegister(opd), tempFloat32()), ins);
 }
 
-void LIRGenerator::visitRandom(MRandom* ins) {
-  LRandom* lir = new (alloc()) LRandom(temp(), temp(), temp());
-  defineFixed(lir, ins, LFloatReg(ReturnDoubleReg));
-}
-
 void LIRGenerator::visitWasmTruncateToInt64(MWasmTruncateToInt64* ins) {
   MDefinition* opd = ins->input();
   MOZ_ASSERT(opd->type() == MIRType::Double || opd->type() == MIRType::Float32);

js/src/jit/shared/LIR-shared.h

@@ -7389,38 +7389,19 @@ class LArrowNewTarget : public LInstructionHelper<BOX_PIECES, 1, 0> {
 };
 
 // Math.random().
-#ifdef JS_PUNBOX64
-#  define LRANDOM_NUM_TEMPS 3
-#else
-#  define LRANDOM_NUM_TEMPS 5
-#endif
-
-class LRandom : public LInstructionHelper<1, 0, LRANDOM_NUM_TEMPS> {
+class LRandom : public LInstructionHelper<1, 0, 1 + 2 * INT64_PIECES> {
  public:
   LIR_HEADER(Random)
-  LRandom(const LDefinition& temp0, const LDefinition& temp1,
-          const LDefinition& temp2
-#ifndef JS_PUNBOX64
-          ,
-          const LDefinition& temp3, const LDefinition& temp4
-#endif
-          )
+  LRandom(const LDefinition& temp0, const LInt64Definition& temp1,
+          const LInt64Definition& temp2)
       : LInstructionHelper(classOpcode) {
     setTemp(0, temp0);
-    setTemp(1, temp1);
-    setTemp(2, temp2);
-#ifndef JS_PUNBOX64
-    setTemp(3, temp3);
-    setTemp(4, temp4);
-#endif
+    setInt64Temp(1, temp1);
+    setInt64Temp(1 + INT64_PIECES, temp2);
   }
   const LDefinition* temp0() { return getTemp(0); }
-  const LDefinition* temp1() { return getTemp(1); }
-  const LDefinition* temp2() { return getTemp(2); }
-#ifndef JS_PUNBOX64
-  const LDefinition* temp3() { return getTemp(3); }
-  const LDefinition* temp4() { return getTemp(4); }
-#endif
+  LInt64Definition temp1() { return getInt64Temp(1); }
+  LInt64Definition temp2() { return getInt64Temp(1 + INT64_PIECES); }
 
   MRandom* mir() const { return mir_->toRandom(); }
 };

js/src/jit/x64/Lowering-x64.cpp

@@ -341,11 +341,6 @@ void LIRGenerator::visitSubstr(MSubstr* ins) {
   assignSafepoint(lir, ins);
 }
 
-void LIRGenerator::visitRandom(MRandom* ins) {
-  LRandom* lir = new (alloc()) LRandom(temp(), temp(), temp());
-  defineFixed(lir, ins, LFloatReg(ReturnDoubleReg));
-}
-
 void LIRGeneratorX64::lowerDivI64(MDiv* div) {
   if (div->isUnsigned()) {
     lowerUDivI64(div);

js/src/jit/x86/Lowering-x86.cpp

@@ -635,11 +635,6 @@ void LIRGenerator::visitSubstr(MSubstr* ins) {
   assignSafepoint(lir, ins);
 }
 
-void LIRGenerator::visitRandom(MRandom* ins) {
-  LRandom* lir = new (alloc()) LRandom(temp(), temp(), temp(), temp(), temp());
-  defineFixed(lir, ins, LFloatReg(ReturnDoubleReg));
-}
-
 void LIRGenerator::visitWasmTruncateToInt64(MWasmTruncateToInt64* ins) {
   MDefinition* opd = ins->input();
   MOZ_ASSERT(opd->type() == MIRType::Double || opd->type() == MIRType::Float32);