Bug 813671 - ModI should not clobber input register, r=jandem.

js/src/ion/shared/CodeGenerator-x86-shared.cpp

@@ -798,10 +798,16 @@ CodeGeneratorX86Shared::visitModI(LModI *ins)
     Register remainder = ToRegister(ins->remainder());
     Register lhs = ToRegister(ins->lhs());
     Register rhs = ToRegister(ins->rhs());
+    Register temp = ToRegister(ins->getTemp(0));
 
     // Required to use idiv.
     JS_ASSERT(remainder == edx);
-    JS_ASSERT(lhs == eax);
+    JS_ASSERT(temp == eax);
+
+    if (lhs != temp) {
+        masm.mov(lhs, temp);
+        lhs = temp;
+    }
 
     // If rhs == 0, bailout, since result must be a double (NaN).
     masm.testl(rhs, rhs);

js/src/ion/shared/LIR-x86-shared.h

@@ -35,9 +35,10 @@ class LModI : public LBinaryMath<1>
   public:
     LIR_HEADER(ModI)
 
-    LModI(const LAllocation &lhs, const LAllocation &rhs) {
+    LModI(const LAllocation &lhs, const LAllocation &rhs, const LDefinition &temp) {
         setOperand(0, lhs);
         setOperand(1, rhs);
+        setTemp(0, temp);
     }
 
     const LDefinition *remainder() {

js/src/ion/shared/Lowering-x86-shared.cpp

@@ -88,7 +88,7 @@ LIRGeneratorX86Shared::lowerModI(MMod *mod)
             return assignSnapshot(lir) && defineReuseInput(lir, mod, 0);
         }
     }
-    LModI *lir = new LModI(useFixed(mod->lhs(), eax), useRegister(mod->rhs()));
+    LModI *lir = new LModI(useRegister(mod->lhs()), useRegister(mod->rhs()), tempFixed(eax));
     return assignSnapshot(lir) && defineFixed(lir, mod, LAllocation(AnyRegister(edx)));
 }