diff --git a/js/src/jit/BaselineIC.cpp b/js/src/jit/BaselineIC.cpp
index 14d43049d3c0..2184400128b4 100644
--- a/js/src/jit/BaselineIC.cpp
+++ b/js/src/jit/BaselineIC.cpp
@@ -4466,7 +4466,7 @@ ICGetElem_Arguments::Compiler::generateStubCode(MacroAssembler &masm)
     regs = availableGeneralRegs(0);
     regs.takeUnchecked(objReg);
     regs.takeUnchecked(idxReg);
-    regs.take(scratchReg);
+    regs.takeUnchecked(scratchReg);
     Register argData = regs.takeAny();
     Register tempReg = regs.takeAny();
 
@@ -4488,7 +4488,6 @@ ICGetElem_Arguments::Compiler::generateStubCode(MacroAssembler &masm)
     masm.addPtr(Imm32(ArgumentsData::offsetOfArgs()), argData);
     regs.add(scratchReg);
     regs.add(tempReg);
-    regs.add(argData);
     ValueOperand tempVal = regs.takeAnyValue();
     masm.loadValue(BaseIndex(argData, idxReg, ScaleFromElemWidth(sizeof(Value))), tempVal);
 
diff --git a/js/src/jit/RegisterSets.h b/js/src/jit/RegisterSets.h
index 251fac45f805..b19d422c3fcc 100644
--- a/js/src/jit/RegisterSets.h
+++ b/js/src/jit/RegisterSets.h
@@ -400,12 +400,8 @@ class TypedRegisterSet
 #endif
     }
     T getAny() const {
-        // The choice of first or last here is mostly arbitrary, as they are
-        // about the same speed on popular architectures. We choose first, as
-        // it has the advantage of using the "lower" registers more often. These
-        // registers are sometimes more efficient (e.g. optimized encodings for
-        // EAX on x86).
-        return getFirst();
+        JS_ASSERT(!empty());
+        return T::FromCode(mozilla::FloorLog2(bits_));
     }
     T getFirst() const {
         JS_ASSERT(!empty());
diff --git a/js/src/jit/arm/MacroAssembler-arm.h b/js/src/jit/arm/MacroAssembler-arm.h
index 5cd54627f98b..5c8e52159d48 100644
--- a/js/src/jit/arm/MacroAssembler-arm.h
+++ b/js/src/jit/arm/MacroAssembler-arm.h
@@ -954,30 +954,12 @@ class MacroAssemblerARMCompat : public MacroAssemblerARM
     void moveValue(const Value &val, const ValueOperand &dest);
 
     void moveValue(const ValueOperand &src, const ValueOperand &dest) {
-        Register s0 = src.typeReg(), d0 = dest.typeReg(),
-                 s1 = src.payloadReg(), d1 = dest.payloadReg();
-
-        // Either one or both of the source registers could be the same as a
-        // destination register.
-        if (s1 == d0) {
-            if (s0 == d1) {
-                // If both are, this is just a swap of two registers.
-                JS_ASSERT(d1 != ScratchRegister);
-                JS_ASSERT(d0 != ScratchRegister);
-                ma_mov(d1, ScratchRegister);
-                ma_mov(d0, d1);
-                ma_mov(ScratchRegister, d0);
-                return;
-            }
-            // If only one is, copy that source first.
-            mozilla::Swap(s0, s1);
-            mozilla::Swap(d0, d1);
-        }
-
-        if (s0 != d0)
-            ma_mov(s0, d0);
-        if (s1 != d1)
-            ma_mov(s1, d1);
+        JS_ASSERT(src.typeReg() != dest.payloadReg());
+        JS_ASSERT(src.payloadReg() != dest.typeReg());
+        if (src.typeReg() != dest.typeReg())
+            ma_mov(src.typeReg(), dest.typeReg());
+        if (src.payloadReg() != dest.payloadReg())
+            ma_mov(src.payloadReg(), dest.payloadReg());
     }
 
     void storeValue(ValueOperand val, Operand dst);
diff --git a/js/src/jit/arm/Trampoline-arm.cpp b/js/src/jit/arm/Trampoline-arm.cpp
index 374f13b44efe..b5ca00421ea0 100644
--- a/js/src/jit/arm/Trampoline-arm.cpp
+++ b/js/src/jit/arm/Trampoline-arm.cpp
@@ -651,7 +651,6 @@ IonRuntime::generateVMWrapper(JSContext *cx, const VMFunction &f)
 
     // The context is the first argument; r0 is the first argument register.
     Register cxreg = r0;
-    regs.take(cxreg);
 
     // Stack is:
     //    ... frame ...
diff --git a/js/src/jit/x86/MacroAssembler-x86.h b/js/src/jit/x86/MacroAssembler-x86.h
index c5a8e9295a06..6fa2c0276635 100644
--- a/js/src/jit/x86/MacroAssembler-x86.h
+++ b/js/src/jit/x86/MacroAssembler-x86.h
@@ -113,26 +113,12 @@ class MacroAssemblerX86 : public MacroAssemblerX86Shared
         moveValue(val, dest.typeReg(), dest.payloadReg());
     }
     void moveValue(const ValueOperand &src, const ValueOperand &dest) {
-        Register s0 = src.typeReg(), d0 = dest.typeReg(),
-                 s1 = src.payloadReg(), d1 = dest.payloadReg();
-
-        // Either one or both of the source registers could be the same as a
-        // destination register.
-        if (s1 == d0) {
-            if (s0 == d1) {
-                // If both are, this is just a swap of two registers.
-                xchgl(d0, d1);
-                return;
-            }
-            // If only one is, copy that source first.
-            mozilla::Swap(s0, s1);
-            mozilla::Swap(d0, d1);
-        }
-
-        if (s0 != d0)
-            movl(s0, d0);
-        if (s1 != d1)
-            movl(s1, d1);
+        JS_ASSERT(src.typeReg() != dest.payloadReg());
+        JS_ASSERT(src.payloadReg() != dest.typeReg());
+        if (src.typeReg() != dest.typeReg())
+            movl(src.typeReg(), dest.typeReg());
+        if (src.payloadReg() != dest.payloadReg())
+            movl(src.payloadReg(), dest.payloadReg());
     }
 
     /////////////////////////////////////////////////////////////////