[flang][NFC] Fix deprecation warning

[tblah]

I started getting deprecation warnings from operations constructors which seem to be doing implicit construction of mlir::ValueRange from a std::nullopt by relying on implicit conversion from std::nullopt into llvm::ArrayRef. ArrayRef{std::nullopt} is what has been deprecated.

[llvmbot]

@llvm/pr-subscribers-flang-fir-hlfir

@llvm/pr-subscribers-flang-codegen

Author: Tom Eccles (tblah)

Changes

I started getting deprecation warnings from operations constructors which seem to be doing implicit construction of mlir::ValueRange from a std::nullopt by relying on implicit conversion from std::nullopt into llvm::ArrayRef. ArrayRef{std::nullopt} is what has been deprecated.

---

Full diff: https://github.com/llvm/llvm-project/pull/147932.diff

2 Files Affected:

• (modified) flang/lib/Optimizer/CodeGen/CodeGen.cpp (+4-4)
• (modified) flang/lib/Optimizer/CodeGen/PreCGRewrite.cpp (+4-3)

diff --git a/flang/lib/Optimizer/CodeGen/CodeGen.cpp b/flang/lib/Optimizer/CodeGen/CodeGen.cpp
index 1bc981516e226..2fe726cbb00e8 100644
--- a/flang/lib/Optimizer/CodeGen/CodeGen.cpp
+++ b/flang/lib/Optimizer/CodeGen/CodeGen.cpp
@@ -2240,7 +2240,7 @@ struct XReboxOpConversion : public EmboxCommonConversion<fir::cg::XReboxOp> {
       if (!rebox.getSubstr().empty())
         substringOffset = operands[rebox.getSubstrOperandIndex()];
       base = genBoxOffsetGep(rewriter, loc, base, llvmBaseObjectType, zero,
-                             /*cstInteriorIndices=*/std::nullopt, fieldIndices,
+                             /*cstInteriorIndices=*/{}, fieldIndices,
                              substringOffset);
     }
 
@@ -2248,7 +2248,7 @@ struct XReboxOpConversion : public EmboxCommonConversion<fir::cg::XReboxOp> {
       // The array section is of the form array[%component][substring], keep
       // the input array extents and strides.
       return finalizeRebox(rebox, adaptor, destBoxTy, dest, base,
-                           /*lbounds*/ std::nullopt, inputExtents, inputStrides,
+                           /*lbounds*/ {}, inputExtents, inputStrides,
                            rewriter);
 
     // The slice is of the form array(i:j:k)[%component]. Compute new extents
@@ -2297,7 +2297,7 @@ struct XReboxOpConversion : public EmboxCommonConversion<fir::cg::XReboxOp> {
       }
     }
     return finalizeRebox(rebox, adaptor, destBoxTy, dest, base,
-                         /*lbounds*/ std::nullopt, slicedExtents, slicedStrides,
+                         /*lbounds*/ {}, slicedExtents, slicedStrides,
                          rewriter);
   }
 
@@ -3396,7 +3396,7 @@ static void genBrOp(A caseOp, mlir::Block *dest, std::optional<B> destOps,
   if (destOps)
     rewriter.replaceOpWithNewOp<mlir::LLVM::BrOp>(caseOp, *destOps, dest);
   else
-    rewriter.replaceOpWithNewOp<mlir::LLVM::BrOp>(caseOp, std::nullopt, dest);
+    rewriter.replaceOpWithNewOp<mlir::LLVM::BrOp>(caseOp, B{}, dest);
 }
 
 static void genCaseLadderStep(mlir::Location loc, mlir::Value cmp,
diff --git a/flang/lib/Optimizer/CodeGen/PreCGRewrite.cpp b/flang/lib/Optimizer/CodeGen/PreCGRewrite.cpp
index d09d7d397e8b7..b60ac11c7795a 100644
--- a/flang/lib/Optimizer/CodeGen/PreCGRewrite.cpp
+++ b/flang/lib/Optimizer/CodeGen/PreCGRewrite.cpp
@@ -107,9 +107,10 @@ class EmboxConversion : public mlir::OpRewritePattern<fir::EmboxOp> {
       shapeOpers.push_back(extVal);
     }
     auto xbox = rewriter.create<fir::cg::XEmboxOp>(
-        loc, embox.getType(), embox.getMemref(), shapeOpers, std::nullopt,
-        std::nullopt, std::nullopt, std::nullopt, embox.getTypeparams(),
-        embox.getSourceBox(), embox.getAllocatorIdxAttr());
+        loc, embox.getType(), embox.getMemref(), shapeOpers, mlir::ValueRange{},
+        mlir::ValueRange{}, mlir::ValueRange{}, mlir::ValueRange{},
+        embox.getTypeparams(), embox.getSourceBox(),
+        embox.getAllocatorIdxAttr());
     LLVM_DEBUG(llvm::dbgs() << "rewriting " << embox << " to " << xbox << '\n');
     rewriter.replaceOp(embox, xbox.getOperation()->getResults());
     return mlir::success();

[tblah]

Ahh this was fixed by #147816

[DanielCChen]

@tblah
Your fix in the PR is less verbose than mine in #147816, which is what @vzakhari prefers.
I would like to switch to your fix if that is OK. Do you want to add on top of #147816 or you prefer me to revert it first?

[github-actions]

✅ With the latest revision this PR passed the C/C++ code formatter.

[DanielCChen]

LGTM.
Thanks!

[tblah]

Windows failure looks like a bot failure.

However it seems MSVC is picking up far more of these deprecation warnings. @DavidTruby please could you look into this when you get time.