Bug 1104658 - Add constant propagation to MMathFunction. r=nbp

js/src/jit/MIR.cpp

@@ -627,14 +627,20 @@ MConstant::New(TempAllocator &alloc, const Value &v, types::CompilerConstraintLi
 }
 
 MConstant *
-MConstant::NewAsmJS(TempAllocator &alloc, const Value &v, MIRType type)
+MConstant::NewTypedValue(TempAllocator &alloc, const Value &v, MIRType type, types::CompilerConstraintList *constraints)
 {
     MOZ_ASSERT(!IsSimdType(type));
-    MConstant *constant = new(alloc) MConstant(v, nullptr);
+    MConstant *constant = new(alloc) MConstant(v, constraints);
     constant->setResultType(type);
     return constant;
 }
 
+MConstant *
+MConstant::NewAsmJS(TempAllocator &alloc, const Value &v, MIRType type)
+{
+    return NewTypedValue(alloc, v, type);
+}
+
 MConstant *
 MConstant::NewConstraintlessObject(TempAllocator &alloc, JSObject *v)
 {
@@ -970,6 +976,101 @@ MMathFunction::printOpcode(FILE *fp) const
     fprintf(fp, " %s", FunctionName(function()));
 }
 
+MDefinition *
+MMathFunction::foldsTo(TempAllocator &alloc)
+{
+    MDefinition *input = getOperand(0);
+    if (!input->isConstant())
+        return this;
+
+    Value val = input->toConstant()->value();
+    if (!val.isNumber())
+        return this;
+
+    double in = val.toNumber();
+    double out;
+    switch (function_) {
+      case Log:
+        out = js::math_log_uncached(in);
+        break;
+      case Sin:
+        out = js::math_sin_uncached(in);
+        break;
+      case Cos:
+        out = js::math_cos_uncached(in);
+        break;
+      case Exp:
+        out = js::math_exp_uncached(in);
+        break;
+      case Tan:
+        out = js::math_tan_uncached(in);
+        break;
+      case ACos:
+        out = js::math_acos_uncached(in);
+        break;
+      case ASin:
+        out = js::math_asin_uncached(in);
+        break;
+      case ATan:
+        out = js::math_atan_uncached(in);
+        break;
+      case Log10:
+        out = js::math_log10_uncached(in);
+        break;
+      case Log2:
+        out = js::math_log2_uncached(in);
+        break;
+      case Log1P:
+        out = js::math_log1p_uncached(in);
+        break;
+      case ExpM1:
+        out = js::math_expm1_uncached(in);
+        break;
+      case CosH:
+        out = js::math_cosh_uncached(in);
+        break;
+      case SinH:
+        out = js::math_sinh_uncached(in);
+        break;
+      case TanH:
+        out = js::math_tanh_uncached(in);
+        break;
+      case ACosH:
+        out = js::math_acosh_uncached(in);
+        break;
+      case ASinH:
+        out = js::math_asinh_uncached(in);
+        break;
+      case ATanH:
+        out = js::math_atanh_uncached(in);
+        break;
+      case Sign:
+        out = js::math_sign_uncached(in);
+        break;
+      case Trunc:
+        out = js::math_trunc_uncached(in);
+        break;
+      case Cbrt:
+        out = js::math_cbrt_uncached(in);
+        break;
+      case Floor:
+        out = js::math_floor_impl(in);
+        break;
+      case Ceil:
+        out = js::math_ceil_impl(in);
+        break;
+      case Round:
+        out = js::math_round_impl(in);
+        break;
+      default:
+        return this;
+    }
+
+    if (input->type() == MIRType_Float32)
+        return MConstant::NewTypedValue(alloc, DoubleValue(out), MIRType_Float32);
+    return MConstant::New(alloc, DoubleValue(out));
+}
+
 MParameter *
 MParameter::New(TempAllocator &alloc, int32_t index, types::TemporaryTypeSet *types)
 {

js/src/jit/MIR.h

@@ -1279,6 +1279,8 @@ class MConstant : public MNullaryInstruction
     INSTRUCTION_HEADER(Constant)
     static MConstant *New(TempAllocator &alloc, const Value &v,
                           types::CompilerConstraintList *constraints = nullptr);
+    static MConstant *NewTypedValue(TempAllocator &alloc, const Value &v, MIRType type,
+                                    types::CompilerConstraintList *constraints = nullptr);
     static MConstant *NewAsmJS(TempAllocator &alloc, const Value &v, MIRType type);
     static MConstant *NewConstraintlessObject(TempAllocator &alloc, JSObject *v);
 
@@ -5703,6 +5705,8 @@ class MMathFunction
         return true;
     }
 
+    MDefinition *foldsTo(TempAllocator &alloc);
+
     void printOpcode(FILE *fp) const MOZ_OVERRIDE;
 
     static const char *FunctionName(Function function);