Merge pull request #199 from Sonicadvance1/ir_has_sideeffects

Implements HasSideEffects IR option

External/FEXCore/Scripts/json_ir_generator.py

@@ -115,6 +115,7 @@ def print_ir_sizes(ops, defines):
     output_file.write("std::string_view const& GetName(IROps Op);\n")
     output_file.write("uint8_t GetArgs(IROps Op);\n")
     output_file.write("FEXCore::IR::RegisterClassType GetRegClass(IROps Op);\n\n")
+    output_file.write("bool HasSideEffects(IROps Op);\n")
 
     output_file.write("#undef IROP_SIZES\n")
     output_file.write("#endif\n\n")
@@ -187,6 +188,25 @@ def print_ir_getraargs(ops, defines):
     output_file.write("#undef IROP_GETRAARGS_IMPL\n")
     output_file.write("#endif\n\n")
 
+def print_ir_hassideeffects(ops, defines):
+    output_file.write("#ifdef IROP_HASSIDEEFFECTS_IMPL\n")
+
+    output_file.write("constexpr std::array<uint8_t, OP_LAST + 1> SideEffects = {\n")
+    for op_key, op_vals in ops.items():
+        HasSideEffects = False
+        if ("HasSideEffects" in op_vals):
+            SSAArgs = op_vals["HasSideEffects"]
+
+        output_file.write("\t%s,\n" % ("true" if SSAArgs else "false"))
+
+    output_file.write("};\n\n")
+
+    output_file.write("bool HasSideEffects(IROps Op) {\n")
+    output_file.write("  return SideEffects[Op];\n")
+    output_file.write("}\n")
+
+    output_file.write("#undef IROP_HASSIDEEFFECTS_IMPL\n")
+    output_file.write("#endif\n\n")
 
 # Print out IR argument printing
 def print_ir_arg_printer(ops, defines):
@@ -619,6 +639,7 @@ print_ir_sizes(ops, defines)
 print_ir_reg_classes(ops, defines)
 print_ir_getname(ops, defines)
 print_ir_getraargs(ops, defines)
+print_ir_hassideeffects(ops, defines)
 print_ir_arg_printer(ops, defines)
 print_ir_allocator_helpers(ops, defines)
 print_ir_parser_allocator_helpers(ops, defines)

External/FEXCore/Source/Interface/IR/IR.cpp

@@ -7,6 +7,7 @@ namespace FEXCore::IR {
 #define IROP_GETNAME_IMPL
 #define IROP_GETRAARGS_IMPL
 #define IROP_REG_CLASSES_IMPL
+#define IROP_HASSIDEEFFECTS_IMPL
 
 #include <FEXCore/IR/IRDefines.inc>
 

External/FEXCore/Source/Interface/IR/IR.json

@@ -41,6 +41,7 @@
 
   "Ops": {
     "Dummy": {
+      "HasSideEffects": true,
       "OpClass": "Misc",
       "SwitchGen": false
     },
@@ -72,6 +73,7 @@
     },
 
     "EndBlock": {
+      "HasSideEffects": true,
       "OpClass": "Misc",
       "SwitchGen": false,
       "Args": [
@@ -103,6 +105,7 @@
     },
 
     "CASPair": {
+      "HasSideEffects": true,
       "OpClass": "Atomic",
       "Desc": ["Does a compare and exchange with two GPRPair values",
                "ssa0 is the comparison value",
@@ -138,6 +141,7 @@
     },
 
     "StoreContextPair": {
+      "HasSideEffects": true,
       "OpClass": "Memory",
       "Desc": ["Stores a pair of values back in to the context"],
       "SSAArgs": "1",
@@ -213,6 +217,7 @@
     },
 
     "Break": {
+      "HasSideEffects": true,
       "OpClass": "Misc",
       "Args": [
         "uint8_t", "Reason",
@@ -221,10 +226,12 @@
     },
 
     "ExitFunction": {
+      "HasSideEffects": true,
       "OpClass": "Branch"
     },
 
     "Jump": {
+      "HasSideEffects": true,
       "OpClass": "Branch",
       "SSAArgs": "1",
       "SSANames": [
@@ -234,6 +241,7 @@
     },
 
     "CondJump": {
+      "HasSideEffects": true,
       "OpClass": "Branch",
       "SSAArgs": "3",
       "RAOverride": "1",
@@ -320,6 +328,7 @@
     },
 
     "StoreContext": {
+      "HasSideEffects": true,
       "Desc": ["Stores a value to the context with offset",
                "Ctx[Offset] = Value"
               ],
@@ -359,6 +368,7 @@
     },
 
     "StoreContextIndexed": {
+      "HasSideEffects": true,
       "Desc": ["Stores a value to the context with offset and indexed by SSA value",
                "Ctx[BaseOffset + Index * Stride] = Value"
               ],
@@ -377,6 +387,7 @@
     },
 
     "SpillRegister": {
+      "HasSideEffects": true,
       "Desc": ["Spills an SSA value to memory",
                "Spill slots are register allocated and has live ranges calculated to handle slot calculation",
                "```diff\n- !Don't use this op. It is for RA to handle spilling and filling!\n```"
@@ -421,6 +432,7 @@
     },
 
     "StoreFlag": {
+      "HasSideEffects": true,
       "Desc": ["Stores 1-bit of the flag in to the specified x86-64 flag",
                "Specialized to allow flexible implementation of flag handling"
               ],
@@ -435,6 +447,7 @@
     },
 
     "Syscall": {
+      "HasSideEffects": true,
       "OpClass": "Branch",
       "HasDest": true,
       "DestClass": "GPR",
@@ -468,6 +481,7 @@
     },
 
     "StoreMem": {
+      "HasSideEffects": true,
       "OpClass": "Memory",
       "SSAArgs": "2",
       "SSANames": [
@@ -900,6 +914,7 @@
     },
 
     "CAS": {
+      "HasSideEffects": true,
       "Desc": ["Does a compare and swap of values to a memory location",
                "This mostly matches the C++ atomic_compare_exchange_strong function",
                "Dest = atomic_compare_exchange_strong(%Addr, %Expected, %Desired)",
@@ -922,6 +937,7 @@
     },
 
     "AtomicAdd": {
+      "HasSideEffects": true,
       "Desc": ["Atomic integer add"
               ],
       "OpClass": "Atomic",
@@ -936,6 +952,7 @@
     },
 
     "AtomicSub": {
+      "HasSideEffects": true,
       "Desc": ["Atomic integer sub"
               ],
       "OpClass": "Atomic",
@@ -950,6 +967,7 @@
     },
 
     "AtomicAnd": {
+      "HasSideEffects": true,
       "Desc": ["Atomic binary and"
               ],
       "OpClass": "Atomic",
@@ -964,6 +982,7 @@
     },
 
     "AtomicOr": {
+      "HasSideEffects": true,
       "Desc": ["Atomic binary or"
               ],
       "OpClass": "Atomic",
@@ -978,6 +997,7 @@
     },
 
     "AtomicXor": {
+      "HasSideEffects": true,
       "Desc": ["Atomic binary exclusive or"
               ],
       "OpClass": "Atomic",
@@ -992,6 +1012,7 @@
     },
 
     "AtomicSwap": {
+      "HasSideEffects": true,
       "Desc": ["Atomic swap",
                "Atomically swaps contents of GPR and memory location"
               ],
@@ -1010,6 +1031,7 @@
     },
 
     "AtomicFetchAdd": {
+      "HasSideEffects": true,
       "Desc": ["Atomic integer fetch and add",
                "Atomically fetches %Addr and adds %value to the memory location",
                "Dest is the value prior to operating on the value in memory"
@@ -1029,6 +1051,7 @@
     },
 
     "AtomicFetchSub": {
+      "HasSideEffects": true,
       "Desc": ["Atomic integer fetch and sub",
                "Atomically fetches %Addr and subtracts %value to the memory location",
                "Dest is the value prior to operating on the value in memory"
@@ -1049,6 +1072,7 @@
     },
 
     "AtomicFetchAnd": {
+      "HasSideEffects": true,
       "Desc": ["Atomic integer fetch and binary and",
                "Atomically fetches %Addr and binary ands %value to the memory location",
                "Dest is the value prior to operating on the value in memory"
@@ -1068,6 +1092,7 @@
     },
 
     "AtomicFetchOr": {
+      "HasSideEffects": true,
       "Desc": ["Atomic integer fetch and binary or",
                "Atomically fetches %Addr and binary ors %value to the memory location",
                "Dest is the value prior to operating on the value in memory"
@@ -1087,6 +1112,7 @@
     },
 
     "AtomicFetchXor": {
+      "HasSideEffects": true,
       "Desc": ["Atomic integer fetch and binary exclusive or",
                "Atomically fetches %Addr and binary exclusive ors %value to the memory location",
                "Dest is the value prior to operating on the value in memory"
@@ -1180,11 +1206,13 @@
     },
 
     "Print": {
+      "HasSideEffects": true,
       "Desc": ["Debug operation that prints an SSA value to the console",
                "May only print 64bits of the value",
                "Depending on backend, may only support GPR printing"
               ],
       "OpClass": "Misc",
+      "DestSize": "GetOpSize(ssa0)",
       "SSAArgs": "1",
       "SSANames": [
         "Value"

External/FEXCore/Source/Interface/IR/Passes/DeadCodeElimination.cpp

@@ -1,6 +1,8 @@
 #include "Interface/IR/PassManager.h"
 #include "Interface/Core/OpcodeDispatcher.h"
 
+#include <FEXCore/IR/IR.h>
+
 #include <array>
 
 namespace FEXCore::IR {
@@ -42,38 +44,13 @@ bool DeadCodeElimination::Run(IREmitter *IREmit) {
       OrderedNode *CodeNode = CodeOp->GetNode(ListBegin);
       auto IROp = CodeNode->Op(DataBegin);
 
-      switch (IROp->Op) {
-      // State/memory storage
-      case OP_STORECONTEXTINDEXED:
-      case OP_STORECONTEXT:
-      case OP_STORECONTEXTPAIR:
-      case OP_STOREFLAG:
-      case OP_STOREMEM:
-      case OP_CAS:
-      case OP_PRINT:
-        // Keep
-        break;
-      // IO
-      case OP_SYSCALL:
-        // Keep
-        break;
-      // Control flow
-      case OP_BREAK:
-      case OP_JUMP:
-      case OP_EXITFUNCTION:
-      case OP_CONDJUMP:
-        // Keep
-        break;
-      case OP_DUMMY:
-      case OP_ENDBLOCK:
-        // Keep, so we don't have to update block first/last
-        break;
-      default:
+      // Skip over anything that has side effects
+      // Use count tracking can't safely remove anything with side effects
+      if (!IR::HasSideEffects(IROp->Op)) {
         if (CodeNode->GetUses() == 0) {
           NumRemoved++;
           IREmit->Remove(CodeNode);
         }
-        break;
       }
 
       if (CodeLast == CodeBegin) {