[flang][NFC] Expose FIR to LLVM patterns (#83492)

The FIR dialect has been initiated before many interfaces have been
introduced to MLIR. This patch expose the FIR to LLVM patterns in a
`populateFIRToLLVMConversionPatterns` function. The idea is to be able
to add the `ConvertToLLVMPatternInterface`. This is not directly
possible since the FIR dialect does not currently use the table
infrastructure for its definition.

Follow up patches will move the FIR dialect definition to table gen and
then implement the interface.

Author: clementval

flang/include/flang/Optimizer/CodeGen/CodeGen.h

@@ -18,6 +18,8 @@
 
 namespace fir {
 
+class LLVMTypeConverter;
+
 struct NameUniquer;
 
 #define GEN_PASS_DECL_FIRTOLLVMLOWERING
@@ -80,6 +82,11 @@ std::unique_ptr<mlir::Pass> createLLVMDialectToLLVMPass(
 std::unique_ptr<mlir::Pass> createBoxedProcedurePass();
 std::unique_ptr<mlir::Pass> createBoxedProcedurePass(bool useThunks);
 
+/// Populate the given list with patterns that convert from FIR to LLVM.
+void populateFIRToLLVMConversionPatterns(fir::LLVMTypeConverter &converter,
+                                         mlir::RewritePatternSet &patterns,
+                                         fir::FIRToLLVMPassOptions &options);
+
 // declarative passes
 #define GEN_PASS_REGISTRATION
 #include "flang/Optimizer/CodeGen/CGPasses.h.inc"

flang/lib/Optimizer/CodeGen/CodeGen.cpp

@@ -3937,30 +3937,7 @@ class FIRToLLVMLowering
                                          options.applyTBAA || applyTBAA,
                                          options.forceUnifiedTBAATree, *dl};
     mlir::RewritePatternSet pattern(context);
-    pattern.insert<
-        AbsentOpConversion, AddcOpConversion, AddrOfOpConversion,
-        AllocaOpConversion, AllocMemOpConversion, BoxAddrOpConversion,
-        BoxCharLenOpConversion, BoxDimsOpConversion, BoxEleSizeOpConversion,
-        BoxIsAllocOpConversion, BoxIsArrayOpConversion, BoxIsPtrOpConversion,
-        BoxOffsetOpConversion, BoxProcHostOpConversion, BoxRankOpConversion,
-        BoxTypeCodeOpConversion, BoxTypeDescOpConversion, CallOpConversion,
-        CmpcOpConversion, ConstcOpConversion, ConvertOpConversion,
-        CoordinateOpConversion, DTEntryOpConversion, DivcOpConversion,
-        EmboxOpConversion, EmboxCharOpConversion, EmboxProcOpConversion,
-        ExtractValueOpConversion, FieldIndexOpConversion, FirEndOpConversion,
-        FreeMemOpConversion, GlobalLenOpConversion, GlobalOpConversion,
-        HasValueOpConversion, InsertOnRangeOpConversion,
-        InsertValueOpConversion, IsPresentOpConversion,
-        LenParamIndexOpConversion, LoadOpConversion, MulcOpConversion,
-        NegcOpConversion, NoReassocOpConversion, SelectCaseOpConversion,
-        SelectOpConversion, SelectRankOpConversion, SelectTypeOpConversion,
-        ShapeOpConversion, ShapeShiftOpConversion, ShiftOpConversion,
-        SliceOpConversion, StoreOpConversion, StringLitOpConversion,
-        SubcOpConversion, TypeDescOpConversion, TypeInfoOpConversion,
-        UnboxCharOpConversion, UnboxProcOpConversion, UndefOpConversion,
-        UnreachableOpConversion, UnrealizedConversionCastOpConversion,
-        XArrayCoorOpConversion, XEmboxOpConversion, XReboxOpConversion,
-        ZeroOpConversion>(typeConverter, options);
+    fir::populateFIRToLLVMConversionPatterns(typeConverter, pattern, options);
     mlir::populateFuncToLLVMConversionPatterns(typeConverter, pattern);
     mlir::populateOpenMPToLLVMConversionPatterns(typeConverter, pattern);
     mlir::arith::populateArithToLLVMConversionPatterns(typeConverter, pattern);
@@ -4072,3 +4049,32 @@ fir::createLLVMDialectToLLVMPass(llvm::raw_ostream &output,
                                  fir::LLVMIRLoweringPrinter printer) {
   return std::make_unique<LLVMIRLoweringPass>(output, printer);
 }
+
+void fir::populateFIRToLLVMConversionPatterns(
+    fir::LLVMTypeConverter &converter, mlir::RewritePatternSet &patterns,
+    fir::FIRToLLVMPassOptions &options) {
+  patterns.insert<
+      AbsentOpConversion, AddcOpConversion, AddrOfOpConversion,
+      AllocaOpConversion, AllocMemOpConversion, BoxAddrOpConversion,
+      BoxCharLenOpConversion, BoxDimsOpConversion, BoxEleSizeOpConversion,
+      BoxIsAllocOpConversion, BoxIsArrayOpConversion, BoxIsPtrOpConversion,
+      BoxOffsetOpConversion, BoxProcHostOpConversion, BoxRankOpConversion,
+      BoxTypeCodeOpConversion, BoxTypeDescOpConversion, CallOpConversion,
+      CmpcOpConversion, ConstcOpConversion, ConvertOpConversion,
+      CoordinateOpConversion, DTEntryOpConversion, DivcOpConversion,
+      EmboxOpConversion, EmboxCharOpConversion, EmboxProcOpConversion,
+      ExtractValueOpConversion, FieldIndexOpConversion, FirEndOpConversion,
+      FreeMemOpConversion, GlobalLenOpConversion, GlobalOpConversion,
+      HasValueOpConversion, InsertOnRangeOpConversion, InsertValueOpConversion,
+      IsPresentOpConversion, LenParamIndexOpConversion, LoadOpConversion,
+      MulcOpConversion, NegcOpConversion, NoReassocOpConversion,
+      SelectCaseOpConversion, SelectOpConversion, SelectRankOpConversion,
+      SelectTypeOpConversion, ShapeOpConversion, ShapeShiftOpConversion,
+      ShiftOpConversion, SliceOpConversion, StoreOpConversion,
+      StringLitOpConversion, SubcOpConversion, TypeDescOpConversion,
+      TypeInfoOpConversion, UnboxCharOpConversion, UnboxProcOpConversion,
+      UndefOpConversion, UnreachableOpConversion,
+      UnrealizedConversionCastOpConversion, XArrayCoorOpConversion,
+      XEmboxOpConversion, XReboxOpConversion, ZeroOpConversion>(converter,
+                                                                options);
+}