JIT: Late expansion for casts

src/coreclr/jit/assertionprop.cpp

@@ -4764,17 +4764,14 @@ GenTree* Compiler::optAssertionProp_Call(ASSERT_VALARG_TP assertions, GenTreeCal
     {
         return optAssertionProp_Update(call, call, stmt);
     }
-    else if (!optLocalAssertionProp && (call->gtCallType == CT_HELPER))
-    {
-        if (call->gtCallMethHnd == eeFindHelper(CORINFO_HELP_ISINSTANCEOFINTERFACE) ||
-            call->gtCallMethHnd == eeFindHelper(CORINFO_HELP_ISINSTANCEOFARRAY) ||
-            call->gtCallMethHnd == eeFindHelper(CORINFO_HELP_ISINSTANCEOFCLASS) ||
-            call->gtCallMethHnd == eeFindHelper(CORINFO_HELP_ISINSTANCEOFANY) ||
-            call->gtCallMethHnd == eeFindHelper(CORINFO_HELP_CHKCASTINTERFACE) ||
-            call->gtCallMethHnd == eeFindHelper(CORINFO_HELP_CHKCASTARRAY) ||
-            call->gtCallMethHnd == eeFindHelper(CORINFO_HELP_CHKCASTCLASS) ||
-            call->gtCallMethHnd == eeFindHelper(CORINFO_HELP_CHKCASTANY) ||
-            call->gtCallMethHnd == eeFindHelper(CORINFO_HELP_CHKCASTCLASS_SPECIAL))
+    else if (!optLocalAssertionProp && call->IsHelperCall())
+    {
+        const CorInfoHelpFunc helper = eeGetHelperNum(call->gtCallMethHnd);
+        if ((helper == CORINFO_HELP_ISINSTANCEOFINTERFACE) || (helper == CORINFO_HELP_ISINSTANCEOFARRAY) ||
+            (helper == CORINFO_HELP_ISINSTANCEOFCLASS) || (helper == CORINFO_HELP_ISINSTANCEOFANY) ||
+            (helper == CORINFO_HELP_CHKCASTINTERFACE) || (helper == CORINFO_HELP_CHKCASTARRAY) ||
+            (helper == CORINFO_HELP_CHKCASTCLASS) || (helper == CORINFO_HELP_CHKCASTANY) ||
+            (helper == CORINFO_HELP_CHKCASTCLASS_SPECIAL))
         {
             GenTree* arg1 = call->gtArgs.GetArgByIndex(1)->GetNode();
             if (arg1->gtOper != GT_LCL_VAR)
@@ -4804,6 +4801,11 @@ GenTree* Compiler::optAssertionProp_Call(ASSERT_VALARG_TP assertions, GenTreeCal
 
                 return optAssertionProp_Update(arg1, call, stmt);
             }
+
+            // TODO-InlineCast: check optAssertionIsNonNull for the object argument and replace
+            // the helper with its nonnull version, e.g.:
+            // CORINFO_HELP_ISINSTANCEOFANY -> CORINFO_HELP_ISINSTANCEOFANY_NONNULL
+            // so then fgLateCastExpansion can skip the null check.
         }
     }
 

src/coreclr/jit/compiler.cpp

@@ -5046,6 +5046,9 @@ void Compiler::compCompile(void** methodCodePtr, uint32_t* methodCodeSize, JitFl
     // Expand thread local access
     DoPhase(this, PHASE_EXPAND_TLS, &Compiler::fgExpandThreadLocalAccess);
 
+    // Expand casts
+    DoPhase(this, PHASE_EXPAND_CASTS, &Compiler::fgLateCastExpansion);
+
     // Insert GC Polls
     DoPhase(this, PHASE_INSERT_GC_POLLS, &Compiler::fgInsertGCPolls);
 

src/coreclr/jit/compiler.h

@@ -5832,6 +5832,9 @@ class Compiler
     bool fgVNBasedIntrinsicExpansionForCall(BasicBlock** pBlock, Statement* stmt, GenTreeCall* call);
     bool fgVNBasedIntrinsicExpansionForCall_ReadUtf8(BasicBlock** pBlock, Statement* stmt, GenTreeCall* call);
 
+    PhaseStatus fgLateCastExpansion();
+    bool fgLateCastExpansionForCall(BasicBlock** pBlock, Statement* stmt, GenTreeCall* call);
+
     PhaseStatus fgInsertGCPolls();
     BasicBlock* fgCreateGCPoll(GCPollType pollType, BasicBlock* block);
 
@@ -7519,6 +7522,7 @@ class Compiler
 #define OMF_HAS_TLS_FIELD                      0x00010000 // Method contains TLS field access
 #define OMF_HAS_SPECIAL_INTRINSICS             0x00020000 // Method contains special intrinsics expanded in late phases
 #define OMF_HAS_RECURSIVE_TAILCALL             0x00040000 // Method contains recursive tail call
+#define OMF_HAS_EXPANDABLE_CAST                0x00080000 // Method contains casts eligible for late expansion
 
     // clang-format on
 
@@ -7559,6 +7563,16 @@ class Compiler
         optMethodFlags |= OMF_HAS_STATIC_INIT;
     }
 
+    bool doesMethodHaveExpandableCasts()
+    {
+        return (optMethodFlags & OMF_HAS_EXPANDABLE_CAST) != 0;
+    }
+
+    void setMethodHasExpandableCasts()
+    {
+        optMethodFlags |= OMF_HAS_EXPANDABLE_CAST;
+    }
+
     bool doesMethodHaveGuardedDevirtualization() const
     {
         return (optMethodFlags & OMF_HAS_GUARDEDDEVIRT) != 0;

src/coreclr/jit/compphases.h

@@ -98,6 +98,7 @@ CompPhaseNameMacro(PHASE_COMPUTE_EDGE_WEIGHTS2,      "Compute edge weights (2, f
 CompPhaseNameMacro(PHASE_STRESS_SPLIT_TREE,          "Stress gtSplitTree",             false, -1, false)
 CompPhaseNameMacro(PHASE_EXPAND_RTLOOKUPS,           "Expand runtime lookups",         false, -1, true)
 CompPhaseNameMacro(PHASE_EXPAND_STATIC_INIT,         "Expand static init",             false, -1, true)
+CompPhaseNameMacro(PHASE_EXPAND_CASTS,               "Expand casts",                   false, -1, true)
 CompPhaseNameMacro(PHASE_EXPAND_TLS,                 "Expand TLS access",              false, -1, true)
 CompPhaseNameMacro(PHASE_INSERT_GC_POLLS,            "Insert GC Polls",                false, -1, true)
 CompPhaseNameMacro(PHASE_CREATE_THROW_HELPERS,       "Create throw helper blocks",     false, -1, true)

src/coreclr/jit/gentree.h

@@ -4080,6 +4080,7 @@ enum GenTreeCallFlags : unsigned int
     GTF_CALL_M_EXPANDED_EARLY          = 0x00800000, // the Virtual Call target address is expanded and placed in gtControlExpr in Morph rather than in Lower
     GTF_CALL_M_HAS_LATE_DEVIRT_INFO    = 0x01000000, // this call has late devirtualzation info
     GTF_CALL_M_LDVIRTFTN_INTERFACE     = 0x02000000, // ldvirtftn on an interface type
+    GTF_CALL_M_CAST_CAN_BE_EXPANDED    = 0x04000000, // this cast (helper call) can be expanded if it's profitable. To be removed.
 };
 
 inline constexpr GenTreeCallFlags operator ~(GenTreeCallFlags a)
@@ -5588,8 +5589,9 @@ struct GenTreeCall final : public GenTree
 
     CORINFO_CLASS_HANDLE gtRetClsHnd; // The return type handle of the call if it is a struct; always available
     union {
-        void*                gtStubCallStubAddr; // GTF_CALL_VIRT_STUB - these are never inlined
-        CORINFO_CLASS_HANDLE gtInitClsHnd;       // Used by static init helpers, represents a class they init
+        void*                gtStubCallStubAddr;   // GTF_CALL_VIRT_STUB - these are never inlined
+        CORINFO_CLASS_HANDLE gtInitClsHnd;         // Used by static init helpers, represents a class they init
+        IL_OFFSET            gtCastHelperILOffset; // Used by cast helpers to save corresponding IL offset
     };
 
     union {