diff --git a/js/src/jit/BaselineBailouts.cpp b/js/src/jit/BaselineBailouts.cpp
index 917206706c74..377cc48ec5cd 100644
--- a/js/src/jit/BaselineBailouts.cpp
+++ b/js/src/jit/BaselineBailouts.cpp
@@ -1726,7 +1726,7 @@ jit::FinishBailoutToBaseline(BaselineBailoutInfo *bailoutInfo)
         // baseline frame.
         return false;
       default:
-        MOZ_ASSUME_UNREACHABLE("Unknown bailout kind!");
+        MOZ_CRASH("Unknown bailout kind!");
     }
 
     if (!CheckFrequentBailouts(cx, outerScript))
diff --git a/js/src/jit/BaselineCompiler.cpp b/js/src/jit/BaselineCompiler.cpp
index 6dbe9e081562..146370445e04 100644
--- a/js/src/jit/BaselineCompiler.cpp
+++ b/js/src/jit/BaselineCompiler.cpp
@@ -1394,7 +1394,7 @@ BaselineCompiler::storeValue(const StackValue *source, const Address &dest,
         masm.storeValue(scratch, dest);
         break;
       default:
-        MOZ_ASSUME_UNREACHABLE("Invalid kind");
+        MOZ_CRASH("Invalid kind");
     }
 }
 
diff --git a/js/src/jit/BaselineDebugModeOSR.cpp b/js/src/jit/BaselineDebugModeOSR.cpp
index c69c6087e117..3091963b2f91 100644
--- a/js/src/jit/BaselineDebugModeOSR.cpp
+++ b/js/src/jit/BaselineDebugModeOSR.cpp
@@ -253,7 +253,7 @@ ICEntryKindToString(ICEntry::Kind kind)
       case ICEntry::Kind_DebugEpilogue:
         return "debug epilogue";
       default:
-        MOZ_ASSUME_UNREACHABLE("bad ICEntry kind");
+        MOZ_CRASH("bad ICEntry kind");
     }
 }
 
@@ -612,7 +612,7 @@ CloneOldBaselineStub(JSContext *cx, DebugModeOSREntryVector &entries, size_t ent
 #undef CASE_KIND
 
       default:
-        MOZ_ASSUME_UNREACHABLE("Bad stub kind");
+        MOZ_CRASH("Bad stub kind");
     }
 
     if (!entry.newStub)
@@ -714,7 +714,7 @@ BaselineDebugModeOSRInfo::popValueInto(PCMappingSlotInfo::SlotLocation loc, Valu
       case PCMappingSlotInfo::SlotIgnore:
         break;
       default:
-        MOZ_ASSUME_UNREACHABLE("Bad slot location");
+        MOZ_CRASH("Bad slot location");
     }
 
     stackAdjust++;
diff --git a/js/src/jit/BaselineFrameInfo.cpp b/js/src/jit/BaselineFrameInfo.cpp
index ee2918e48134..c00ff7d56811 100644
--- a/js/src/jit/BaselineFrameInfo.cpp
+++ b/js/src/jit/BaselineFrameInfo.cpp
@@ -46,7 +46,7 @@ FrameInfo::sync(StackValue *val)
         masm.pushValue(val->constant());
         break;
       default:
-        MOZ_ASSUME_UNREACHABLE("Invalid kind");
+        MOZ_CRASH("Invalid kind");
     }
 
     val->setStack();
@@ -102,7 +102,7 @@ FrameInfo::popValue(ValueOperand dest)
         masm.moveValue(val->reg(), dest);
         break;
       default:
-        MOZ_ASSUME_UNREACHABLE("Invalid kind");
+        MOZ_CRASH("Invalid kind");
     }
 
     // masm.popValue already adjusted the stack pointer, don't do it twice.
@@ -138,7 +138,7 @@ FrameInfo::popRegsAndSync(uint32_t uses)
         break;
       }
       default:
-        MOZ_ASSUME_UNREACHABLE("Invalid uses");
+        MOZ_CRASH("Invalid uses");
     }
 }
 
@@ -175,7 +175,7 @@ FrameInfo::assertValidState(const BytecodeInfo &info)
                 JS_ASSERT(!usedR1);
                 usedR1 = true;
             } else {
-                MOZ_ASSUME_UNREACHABLE("Invalid register");
+                MOZ_CRASH("Invalid register");
             }
         }
     }
diff --git a/js/src/jit/BaselineIC.cpp b/js/src/jit/BaselineIC.cpp
index d2d2adb7e568..80078f7ad384 100644
--- a/js/src/jit/BaselineIC.cpp
+++ b/js/src/jit/BaselineIC.cpp
@@ -253,7 +253,7 @@ ICStub::trace(JSTracer *trc)
           case 2: setElemStub->toImpl<2>()->traceShapes(trc); break;
           case 3: setElemStub->toImpl<3>()->traceShapes(trc); break;
           case 4: setElemStub->toImpl<4>()->traceShapes(trc); break;
-          default: MOZ_ASSUME_UNREACHABLE("Invalid proto stub.");
+          default: MOZ_CRASH("Invalid proto stub.");
         }
         break;
       }
@@ -348,7 +348,7 @@ ICStub::trace(JSTracer *trc)
           case 6: propStub->toImpl<6>()->traceShapes(trc); break;
           case 7: propStub->toImpl<7>()->traceShapes(trc); break;
           case 8: propStub->toImpl<8>()->traceShapes(trc); break;
-          default: MOZ_ASSUME_UNREACHABLE("Invalid proto stub.");
+          default: MOZ_CRASH("Invalid proto stub.");
         }
         break;
       }
@@ -415,7 +415,7 @@ ICStub::trace(JSTracer *trc)
           case 2: propStub->toImpl<2>()->traceShapes(trc); break;
           case 3: propStub->toImpl<3>()->traceShapes(trc); break;
           case 4: propStub->toImpl<4>()->traceShapes(trc); break;
-          default: MOZ_ASSUME_UNREACHABLE("Invalid proto stub.");
+          default: MOZ_CRASH("Invalid proto stub.");
         }
         break;
       }
@@ -827,7 +827,7 @@ EnsureCanEnterIon(JSContext *cx, ICUseCount_Fallback *stub, BaselineFrame *frame
     else if (stat == Method_Compiled)
         IonSpew(IonSpew_BaselineOSR, "  Compiled with Ion!");
     else
-        MOZ_ASSUME_UNREACHABLE("Invalid MethodStatus!");
+        MOZ_CRASH("Invalid MethodStatus!");
 
     // Failed to compile.  Reset use count and return.
     if (stat != Method_Compiled) {
@@ -1544,7 +1544,7 @@ DoTypeUpdateFallback(JSContext *cx, BaselineFrame *frame, ICUpdatedStub *stub, H
         break;
       }
       default:
-        MOZ_ASSUME_UNREACHABLE("Invalid stub");
+        MOZ_CRASH("Invalid stub");
     }
 
     return stub->addUpdateStubForValue(cx, script, obj, id, value);
@@ -2590,7 +2590,7 @@ DoBinaryArithFallback(JSContext *cx, BaselineFrame *frame, ICBinaryArith_Fallbac
         break;
       }
       default:
-        MOZ_ASSUME_UNREACHABLE("Unhandled baseline arith op");
+        MOZ_CRASH("Unhandled baseline arith op");
     }
 
     // Check if debug mode toggling made the stub invalid.
@@ -2914,7 +2914,7 @@ ICBinaryArith_Double::Compiler::generateStubCode(MacroAssembler &masm)
         JS_ASSERT(ReturnDoubleReg == FloatReg0);
         break;
       default:
-        MOZ_ASSUME_UNREACHABLE("Unexpected op");
+        MOZ_CRASH("Unexpected op");
     }
 
     masm.boxDouble(FloatReg0, R0);
@@ -2992,7 +2992,7 @@ ICBinaryArith_BooleanWithInt32::Compiler::generateStubCode(MacroAssembler &masm)
         break;
       }
       default:
-       MOZ_ASSUME_UNREACHABLE("Unhandled op for BinaryArith_BooleanWithInt32.");
+       MOZ_CRASH("Unhandled op for BinaryArith_BooleanWithInt32.");
     }
 
     // Failure case - jump to next stub
@@ -3054,7 +3054,7 @@ ICBinaryArith_DoubleWithInt32::Compiler::generateStubCode(MacroAssembler &masm)
         masm.andPtr(intReg, intReg2);
         break;
       default:
-       MOZ_ASSUME_UNREACHABLE("Unhandled op for BinaryArith_DoubleWithInt32.");
+       MOZ_CRASH("Unhandled op for BinaryArith_DoubleWithInt32.");
     }
     masm.tagValue(JSVAL_TYPE_INT32, intReg2, R0);
     EmitReturnFromIC(masm);
@@ -3098,7 +3098,7 @@ DoUnaryArithFallback(JSContext *cx, BaselineFrame *frame, ICUnaryArith_Fallback
             return false;
         break;
       default:
-        MOZ_ASSUME_UNREACHABLE("Unexpected op");
+        MOZ_CRASH("Unexpected op");
     }
 
     // Check if debug mode toggling made the stub invalid.
@@ -3738,7 +3738,7 @@ RemoveExistingGetElemNativeStubs(JSContext *cx, ICGetElem_Fallback *stub, Handle
 
         // Should never get here, because this means a matching stub exists, and if
         // a matching stub exists, this procedure should never have been called.
-        MOZ_ASSUME_UNREACHABLE("Procedure should never have been called.");
+        MOZ_CRASH("Procedure should never have been called.");
     }
 }
 
@@ -5354,7 +5354,7 @@ ICSetElemDenseAddCompiler::getStub(ICStubSpace *space)
       case 2: stub = getStubSpecific<2>(space, &shapes); break;
       case 3: stub = getStubSpecific<3>(space, &shapes); break;
       case 4: stub = getStubSpecific<4>(space, &shapes); break;
-      default: MOZ_ASSUME_UNREACHABLE("ProtoChainDepth too high.");
+      default: MOZ_CRASH("ProtoChainDepth too high.");
     }
     if (!stub || !stub->initUpdatingChain(cx, space))
         return nullptr;
@@ -6714,7 +6714,7 @@ ICGetProp_Primitive::Compiler::generateStubCode(MacroAssembler &masm)
         masm.branchTestBoolean(Assembler::NotEqual, R0, &failure);
         break;
       default:
-        MOZ_ASSUME_UNREACHABLE("unexpected type");
+        MOZ_CRASH("unexpected type");
     }
 
     GeneralRegisterSet regs(availableGeneralRegs(1));
@@ -6869,7 +6869,7 @@ ICGetPropNativeDoesNotExistCompiler::getStub(ICStubSpace *space)
       case 6: stub = getStubSpecific<6>(space, &shapes); break;
       case 7: stub = getStubSpecific<7>(space, &shapes); break;
       case 8: stub = getStubSpecific<8>(space, &shapes); break;
-      default: MOZ_ASSUME_UNREACHABLE("ProtoChainDepth too high.");
+      default: MOZ_CRASH("ProtoChainDepth too high.");
     }
     if (!stub)
         return nullptr;
@@ -7748,7 +7748,7 @@ ICSetPropNativeAddCompiler::getStub(ICStubSpace *space)
       case 2: stub = getStubSpecific<2>(space, &shapes); break;
       case 3: stub = getStubSpecific<3>(space, &shapes); break;
       case 4: stub = getStubSpecific<4>(space, &shapes); break;
-      default: MOZ_ASSUME_UNREACHABLE("ProtoChainDepth too high.");
+      default: MOZ_CRASH("ProtoChainDepth too high.");
     }
     if (!stub || !stub->initUpdatingChain(cx, space))
         return nullptr;
@@ -10051,7 +10051,7 @@ ICTypeOf_Typed::Compiler::generateStubCode(MacroAssembler &masm)
         break;
 
       default:
-        MOZ_ASSUME_UNREACHABLE("Unexpected type");
+        MOZ_CRASH("Unexpected type");
     }
 
     masm.movePtr(ImmGCPtr(typeString_), R0.scratchReg());
diff --git a/js/src/jit/BaselineIC.h b/js/src/jit/BaselineIC.h
index a95143421f7d..3997c1061d9a 100644
--- a/js/src/jit/BaselineIC.h
+++ b/js/src/jit/BaselineIC.h
@@ -595,7 +595,7 @@ class ICStub
             IC_STUB_KIND_LIST(DEF_KIND_STR)
 #undef DEF_KIND_STR
           default:
-            MOZ_ASSUME_UNREACHABLE("Invalid kind.");
+            MOZ_CRASH("Invalid kind.");
         }
     }
 
@@ -1130,7 +1130,7 @@ class ICStubCompiler
             regs.take(R1);
             break;
           default:
-            MOZ_ASSUME_UNREACHABLE("Invalid numInputs");
+            MOZ_CRASH("Invalid numInputs");
         }
 
         return regs;
@@ -3306,8 +3306,7 @@ class ICGetElemNativeCompiler : public ICStubCompiler
                     getter_, pcOffset_, holder_, holderShape);
         }
 
-        MOZ_ASSUME_UNREACHABLE("Invalid kind.");
-        return nullptr;
+        MOZ_CRASH("Invalid kind.");
     }
 };
 
diff --git a/js/src/jit/BaselineJIT.cpp b/js/src/jit/BaselineJIT.cpp
index ea633cc36b87..ae37f490f617 100644
--- a/js/src/jit/BaselineJIT.cpp
+++ b/js/src/jit/BaselineJIT.cpp
@@ -530,7 +530,7 @@ BaselineScript::icEntryFromPCOffset(uint32_t pcOffset)
         if (icEntry(i).isForOp())
             return icEntry(i);
     }
-    MOZ_ASSUME_UNREACHABLE("Invalid PC offset for IC entry.");
+    MOZ_CRASH("Invalid PC offset for IC entry.");
 }
 
 ICEntry &
@@ -672,8 +672,6 @@ BaselineScript::nativeCodeForPC(JSScript *script, jsbytecode *pc, PCMappingSlotI
 
         curPC += GetBytecodeLength(curPC);
     }
-
-    MOZ_ASSUME_UNREACHABLE("Invalid pc");
 }
 
 jsbytecode *
@@ -748,8 +746,6 @@ BaselineScript::pcForNativeOffset(JSScript *script, uint32_t nativeOffset, bool
 
         curPC += GetBytecodeLength(curPC);
     }
-
-    MOZ_ASSUME_UNREACHABLE("Bad baseline jitcode address");
 }
 
 jsbytecode *
diff --git a/js/src/jit/VMFunctions.cpp b/js/src/jit/VMFunctions.cpp
index b86020a7d457..31df4ba65a6b 100644
--- a/js/src/jit/VMFunctions.cpp
+++ b/js/src/jit/VMFunctions.cpp
@@ -813,7 +813,7 @@ DebugPrologue(JSContext *cx, BaselineFrame *frame, jsbytecode *pc, bool *mustRet
         return false;
 
       default:
-        MOZ_ASSUME_UNREACHABLE("Invalid trap status");
+        MOZ_CRASH("Invalid trap status");
     }
 }
 
@@ -965,7 +965,7 @@ HandleDebugTrap(JSContext *cx, BaselineFrame *frame, uint8_t *retAddr, bool *mus
         return false;
 
       default:
-        MOZ_ASSUME_UNREACHABLE("Invalid trap status");
+        MOZ_CRASH("Invalid trap status");
     }
 
     return true;
@@ -996,7 +996,7 @@ OnDebuggerStatement(JSContext *cx, BaselineFrame *frame, jsbytecode *pc, bool *m
         return false;
 
       default:
-        MOZ_ASSUME_UNREACHABLE("Invalid trap status");
+        MOZ_CRASH("Invalid trap status");
     }
 }