Use 0 instead of undefined as the replacement in FuncSigOpts

Summary:
`0` is faster to create at runtime than `undefined`.
Therefore, change the unused arguments to pass `0` during FuncSigOpts.

Reviewed By: neildhar

Differential Revision: D42999599

fbshipit-source-id: 222d982c5438f094b7bcbfb8dc7a2d3a2637b238

lib/Optimizer/Scalar/FuncSigOpts.cpp

@@ -169,15 +169,16 @@ static bool performFSO(Function *F, std::vector<Function *> &worklist) {
 
   llvh::DenseSet<Function *> toRedo;
 
-  // Replace all unused arguments with undef.
+  // Replace all unused arguments with 0 (which is cheap to create).
+  Literal *zero = builder.getLiteralPositiveZero();
   for (auto &arg : unusedParams) {
     Value *prevArg = arg.call->getArgument(arg.idx);
     if (!llvh::isa<Literal>(prevArg))
       toRedo.insert(arg.call->getParent()->getParent());
 
-    arg.call->setArgument(undef, arg.idx);
+    arg.call->setArgument(zero, arg.idx);
     if (arg.param)
-      arg.param->setType(Type::createUndefined());
+      arg.param->setType(Type::createUint32());
     NumArgsOpt++;
   }
 

test/Optimizer/callee.js

@@ -70,7 +70,7 @@ function load_store_multiple_test() {
 // CHECK-NEXT:frame = []
 // CHECK-NEXT:%BB0:
 // CHECK-NEXT:  %0 = CreateFunctionInst (:object) %foo(): number
-// CHECK-NEXT:  %1 = CallInst (:number) %0: object, %foo(): number, empty: any, undefined: undefined, 12: number
+// CHECK-NEXT:  %1 = CallInst (:number) %0: object, %foo(): number, empty: any, 0: number, 12: number
 // CHECK-NEXT:  %2 = ReturnInst 12: number
 // CHECK-NEXT:function_end
 
@@ -80,7 +80,7 @@ function load_store_multiple_test() {
 // CHECK-NEXT:  %0 = CreateFunctionInst (:object) %"foo 1#"(): number
 // CHECK-NEXT:  %1 = LoadPropertyInst (:any) %0: object, "prototype": string
 // CHECK-NEXT:  %2 = CreateThisInst (:object) %1: any, %0: object
-// CHECK-NEXT:  %3 = ConstructInst (:number) %0: object, %"foo 1#"(): number, empty: any, undefined: undefined, 12: number
+// CHECK-NEXT:  %3 = ConstructInst (:number) %0: object, %"foo 1#"(): number, empty: any, 0: number, 12: number
 // CHECK-NEXT:  %4 = ReturnInst %2: object
 // CHECK-NEXT:function_end
 
@@ -90,7 +90,7 @@ function load_store_multiple_test() {
 // CHECK-NEXT:  %0 = CreateFunctionInst (:object) %ping(): number
 // CHECK-NEXT:  %1 = CreateFunctionInst (:object) %k(): number
 // CHECK-NEXT:  %2 = StoreFrameInst %1: object, [k]: object
-// CHECK-NEXT:  %3 = CallInst (:number) %0: object, %ping(): number, empty: any, undefined: undefined
+// CHECK-NEXT:  %3 = CallInst (:number) %0: object, %ping(): number, empty: any, 0: number
 // CHECK-NEXT:  %4 = ReturnInst 123: number
 // CHECK-NEXT:function_end
 
@@ -100,7 +100,7 @@ function load_store_multiple_test() {
 // CHECK-NEXT:  %0 = CreateFunctionInst (:object) %"foo 2#"(): number
 // CHECK-NEXT:  %1 = StoreFrameInst %0: object, [foo]: object
 // CHECK-NEXT:  %2 = CreateFunctionInst (:object) %bar(): number
-// CHECK-NEXT:  %3 = CallInst (:number) %2: object, %bar(): number, empty: any, undefined: undefined
+// CHECK-NEXT:  %3 = CallInst (:number) %2: object, %bar(): number, empty: any, 0: number
 // CHECK-NEXT:  %4 = ReturnInst %3: number
 // CHECK-NEXT:function_end
 
@@ -120,7 +120,7 @@ function load_store_multiple_test() {
 // CHECK-NEXT:frame = []
 // CHECK-NEXT:%BB0:
 // CHECK-NEXT:  %0 = LoadFrameInst (:object) [k@load_store_test]: object
-// CHECK-NEXT:  %1 = CallInst (:number) %0: object, %k(): number, empty: any, undefined: undefined, 123: number
+// CHECK-NEXT:  %1 = CallInst (:number) %0: object, %k(): number, empty: any, 0: number, 123: number
 // CHECK-NEXT:  %2 = ReturnInst 123: number
 // CHECK-NEXT:function_end
 
@@ -141,8 +141,8 @@ function load_store_multiple_test() {
 // CHECK-NEXT:frame = []
 // CHECK-NEXT:%BB0:
 // CHECK-NEXT:  %0 = LoadFrameInst (:object) [foo@load_store_multiple_test]: object
-// CHECK-NEXT:  %1 = CallInst (:number) %0: object, %"foo 2#"(): number, empty: any, undefined: undefined, true: boolean, 7: number
-// CHECK-NEXT:  %2 = CallInst (:number) %0: object, %"foo 2#"(): number, empty: any, undefined: undefined, true: boolean, 8: number
+// CHECK-NEXT:  %1 = CallInst (:number) %0: object, %"foo 2#"(): number, empty: any, 0: number, true: boolean, 7: number
+// CHECK-NEXT:  %2 = CallInst (:number) %0: object, %"foo 2#"(): number, empty: any, 0: number, true: boolean, 8: number
 // CHECK-NEXT:  %3 = BinaryAddInst (:number) %1: number, %2: number
 // CHECK-NEXT:  %4 = ReturnInst %3: number
 // CHECK-NEXT:function_end

test/Optimizer/constructor_callee.js

@@ -60,7 +60,7 @@ function ctor_load_store_test() {
 // CHECK-NEXT:  %0 = CreateFunctionInst (:object) %"use_this 1#"(): undefined
 // CHECK-NEXT:  %1 = StoreFrameInst %0: object, [use_this]: object
 // CHECK-NEXT:  %2 = CreateFunctionInst (:object) %construct_use_this(): object
-// CHECK-NEXT:  %3 = CallInst (:object) %2: object, %construct_use_this(): object, empty: any, undefined: undefined
+// CHECK-NEXT:  %3 = CallInst (:object) %2: object, %construct_use_this(): object, empty: any, 0: number
 // CHECK-NEXT:  %4 = ReturnInst %3: object
 // CHECK-NEXT:function_end
 

test/Optimizer/func_sig_opts.js

@@ -89,7 +89,7 @@ function test_async() {
 // CHECK-NEXT:  %1 = CreateFunctionInst (:object) %foo(): number
 // CHECK-NEXT:  %2 = CreateFunctionInst (:object) %bar(): string|number|bigint
 // CHECK-NEXT:  %3 = StorePropertyStrictInst %2: object, %0: any, "p": string
-// CHECK-NEXT:  %4 = CallInst (:number) %1: object, %foo(): number, empty: any, undefined: undefined, 1: number, 2: number
+// CHECK-NEXT:  %4 = CallInst (:number) %1: object, %foo(): number, empty: any, 0: number, 1: number, 2: number
 // CHECK-NEXT:  %5 = CallInst (:string|number|bigint) %2: object, %bar(): string|number|bigint, empty: any, undefined: undefined, 1: number, 2: number
 // CHECK-NEXT:  %6 = BinaryAddInst (:string|number) %4: number, %5: string|number|bigint
 // CHECK-NEXT:  %7 = ReturnInst %6: string|number
@@ -99,8 +99,8 @@ function test_async() {
 // CHECK-NEXT:frame = []
 // CHECK-NEXT:%BB0:
 // CHECK-NEXT:  %0 = CreateFunctionInst (:object) %builder(): number
-// CHECK-NEXT:  %1 = CallInst (:number) %0: object, %builder(): number, empty: any, undefined: undefined
-// CHECK-NEXT:  %2 = CallInst (:number) %0: object, %builder(): number, empty: any, undefined: undefined
+// CHECK-NEXT:  %1 = CallInst (:number) %0: object, %builder(): number, empty: any, 0: number
+// CHECK-NEXT:  %2 = CallInst (:number) %0: object, %builder(): number, empty: any, 0: number
 // CHECK-NEXT:  %3 = BinaryAddInst (:number) %1: number, %2: number
 // CHECK-NEXT:  %4 = ReturnInst %3: number
 // CHECK-NEXT:function_end
@@ -166,7 +166,7 @@ function test_async() {
 // CHECK-NEXT:  %2 = ReturnInst %1: number
 // CHECK-NEXT:function_end
 
-// CHECK:function foo2(a: any, b: number, c: number, d: undefined): string|number [allCallsitesKnownInStrictMode]
+// CHECK:function foo2(a: any, b: number, c: number, d: number): string|number [allCallsitesKnownInStrictMode]
 // CHECK-NEXT:frame = []
 // CHECK-NEXT:%BB0:
 // CHECK-NEXT:  %0 = LoadParamInst (:any) %a: any
@@ -181,7 +181,7 @@ function test_async() {
 // CHECK-NEXT:%BB0:
 // CHECK-NEXT:  %0 = LoadParamInst (:any) %e: any
 // CHECK-NEXT:  %1 = LoadFrameInst (:object) [foo2@test_unused_and_duplicate_params]: object
-// CHECK-NEXT:  %2 = CallInst (:string|number) %1: object, %foo2(): string|number, empty: any, undefined: undefined, %0: any, 2: number, 1: number, undefined: undefined, undefined: undefined, undefined: undefined
+// CHECK-NEXT:  %2 = CallInst (:string|number) %1: object, %foo2(): string|number, empty: any, 0: number, %0: any, 2: number, 1: number, 0: number, 0: number, 0: number
 // CHECK-NEXT:  %3 = ReturnInst undefined: undefined
 // CHECK-NEXT:function_end
 
@@ -190,7 +190,7 @@ function test_async() {
 // CHECK-NEXT:%BB0:
 // CHECK-NEXT:  %0 = LoadParamInst (:any) %e: any
 // CHECK-NEXT:  %1 = LoadFrameInst (:object) [foo2@test_unused_and_duplicate_params]: object
-// CHECK-NEXT:  %2 = CallInst (:string|number) %1: object, %foo2(): string|number, empty: any, undefined: undefined, %0: any, 2: number, 3: number, undefined: undefined, undefined: undefined
+// CHECK-NEXT:  %2 = CallInst (:string|number) %1: object, %foo2(): string|number, empty: any, 0: number, %0: any, 2: number, 3: number, 0: number, 0: number
 // CHECK-NEXT:  %3 = ReturnInst undefined: undefined
 // CHECK-NEXT:function_end
 

test/Optimizer/function-analysis-call-closure.js

@@ -30,7 +30,7 @@ function main() {
 // CHECK-NEXT:frame = []
 // CHECK-NEXT:%BB0:
 // CHECK-NEXT:  %0 = CreateFunctionInst (:object) %f(): undefined
-// CHECK-NEXT:  %1 = CallInst (:undefined) %0: object, %f(): undefined, empty: any, undefined: undefined
+// CHECK-NEXT:  %1 = CallInst (:undefined) %0: object, %f(): undefined, empty: any, 0: number
 // CHECK-NEXT:  %2 = ReturnInst undefined: undefined
 // CHECK-NEXT:function_end
 

test/Optimizer/function-analysis-chained-vars.js

@@ -41,7 +41,7 @@ function main() {
 // CHECK-NEXT:  %0 = CreateFunctionInst (:object) %foo(): object
 // CHECK-NEXT:  %1 = CreateFunctionInst (:object) %x(): number
 // CHECK-NEXT:  %2 = StoreFrameInst %1: object, [x]: object
-// CHECK-NEXT:  %3 = CallInst (:object) %0: object, %foo(): object, empty: any, undefined: undefined
+// CHECK-NEXT:  %3 = CallInst (:object) %0: object, %foo(): object, empty: any, 0: number
 // CHECK-NEXT:  %4 = ReturnInst undefined: undefined
 // CHECK-NEXT:function_end
 
@@ -64,6 +64,6 @@ function main() {
 // CHECK-NEXT:frame = []
 // CHECK-NEXT:%BB0:
 // CHECK-NEXT:  %0 = LoadFrameInst (:object) [y@foo]: object
-// CHECK-NEXT:  %1 = CallInst (:number) %0: object, %x(): number, empty: any, undefined: undefined
+// CHECK-NEXT:  %1 = CallInst (:number) %0: object, %x(): number, empty: any, 0: number
 // CHECK-NEXT:  %2 = ReturnInst undefined: undefined
 // CHECK-NEXT:function_end

test/Optimizer/function-analysis-construction-store.js

@@ -33,7 +33,7 @@ function main() {
 // CHECK-NEXT:  %0 = CreateFunctionInst (:object) %f(): undefined
 // CHECK-NEXT:  %1 = LoadPropertyInst (:any) %0: object, "prototype": string
 // CHECK-NEXT:  %2 = CreateThisInst (:object) %1: any, %0: object
-// CHECK-NEXT:  %3 = ConstructInst (:undefined) %0: object, %f(): undefined, empty: any, undefined: undefined
+// CHECK-NEXT:  %3 = ConstructInst (:undefined) %0: object, %f(): undefined, empty: any, 0: number
 // CHECK-NEXT:  %4 = ReturnInst %2: object
 // CHECK-NEXT:function_end
 

test/Optimizer/function-analysis-construction.js

@@ -32,7 +32,7 @@ function main() {
 // CHECK-NEXT:  %0 = CreateFunctionInst (:object) %f(): undefined
 // CHECK-NEXT:  %1 = LoadPropertyInst (:any) %0: object, "prototype": string
 // CHECK-NEXT:  %2 = CreateThisInst (:object) %1: any, %0: object
-// CHECK-NEXT:  %3 = ConstructInst (:undefined) %0: object, %f(): undefined, empty: any, undefined: undefined
+// CHECK-NEXT:  %3 = ConstructInst (:undefined) %0: object, %f(): undefined, empty: any, 0: number
 // CHECK-NEXT:  %4 = ReturnInst %2: object
 // CHECK-NEXT:function_end
 

test/Optimizer/function-analysis-single-store.js

@@ -30,7 +30,7 @@ function main(x) {
 // CHECK-NEXT:frame = []
 // CHECK-NEXT:%BB0:
 // CHECK-NEXT:  %0 = CreateFunctionInst (:object) %f(): undefined
-// CHECK-NEXT:  %1 = CallInst (:undefined) %0: object, %f(): undefined, empty: any, undefined: undefined
+// CHECK-NEXT:  %1 = CallInst (:undefined) %0: object, %f(): undefined, empty: any, 0: number
 // CHECK-NEXT:  %2 = ReturnInst undefined: undefined
 // CHECK-NEXT:function_end
 

test/Optimizer/inline-directive.js

@@ -25,7 +25,7 @@
 // CHECK-NEXT:frame = []
 // CHECK-NEXT:%BB0:
 // CHECK-NEXT:  %0 = CreateFunctionInst (:object) %""(): number
-// CHECK-NEXT:  %1 = CallInst (:number) %0: object, %""(): number, empty: any, undefined: undefined
+// CHECK-NEXT:  %1 = CallInst (:number) %0: object, %""(): number, empty: any, 0: number
 // CHECK-NEXT:  %2 = ReturnInst %1: number
 // CHECK-NEXT:function_end
 

test/Optimizer/inline-recursive.js

@@ -37,6 +37,6 @@
 // CHECK-NEXT:frame = []
 // CHECK-NEXT:%BB0:
 // CHECK-NEXT:  %0 = LoadFrameInst (:object) [f@main]: object
-// CHECK-NEXT:  %1 = CallInst (:any) %0: object, %f(): any, empty: any, undefined: undefined
+// CHECK-NEXT:  %1 = CallInst (:any) %0: object, %f(): any, empty: any, 0: number
 // CHECK-NEXT:  %2 = ReturnInst %1: any
 // CHECK-NEXT:function_end

test/Optimizer/inline-unreachable-2.js

@@ -26,7 +26,7 @@
 // CHECK-NEXT:frame = []
 // CHECK-NEXT:%BB0:
 // CHECK-NEXT:  %0 = CreateFunctionInst (:object) %main(): undefined
-// CHECK-NEXT:  %1 = CallInst (:undefined) %0: object, %main(): undefined, empty: any, undefined: undefined
+// CHECK-NEXT:  %1 = CallInst (:undefined) %0: object, %main(): undefined, empty: any, 0: number
 // CHECK-NEXT:  %2 = ReturnInst undefined: undefined
 // CHECK-NEXT:function_end