[mlir][toy] Use make_early_inc_range when erasing ops during iteration

[matthias-springer]

Use make_early_inc_range when erasing operations from a block to make sure that the iterator is not invalidated. The previous implementation happened to work on a "normal" dialect conversion because some IR modifications are delayed. It no longer works with a One-Shot Dialect Conversion. The new One-Shot Dialect Conversion API is more similar to the normal rewriter API.

[llvmbot]

@llvm/pr-subscribers-mlir

Author: Matthias Springer (matthias-springer)

Changes

Use make_early_inc_range when erasing operations from a block to make sure that the iterator is not invalidated. The previous implementation happened to work on a "normal" dialect conversion because some IR modifications are delayed. It no longer works with a One-Shot Dialect Conversion. The new One-Shot Dialect Conversion API is more similar to the normal rewriter API.

---

Full diff: https://github.com/llvm/llvm-project/pull/146892.diff

2 Files Affected:

• (modified) mlir/examples/toy/Ch6/mlir/LowerToLLVM.cpp (+1-1)
• (modified) mlir/examples/toy/Ch7/mlir/LowerToLLVM.cpp (+1-1)

diff --git a/mlir/examples/toy/Ch6/mlir/LowerToLLVM.cpp b/mlir/examples/toy/Ch6/mlir/LowerToLLVM.cpp
index de1eafc4d8678..22f75e042fe08 100644
--- a/mlir/examples/toy/Ch6/mlir/LowerToLLVM.cpp
+++ b/mlir/examples/toy/Ch6/mlir/LowerToLLVM.cpp
@@ -92,7 +92,7 @@ class PrintOpLowering : public ConversionPattern {
       auto step = rewriter.create<arith::ConstantIndexOp>(loc, 1);
       auto loop =
           rewriter.create<scf::ForOp>(loc, lowerBound, upperBound, step);
-      for (Operation &nested : *loop.getBody())
+      for (Operation &nested : make_early_inc_range(*loop.getBody()))
         rewriter.eraseOp(&nested);
       loopIvs.push_back(loop.getInductionVar());
 
diff --git a/mlir/examples/toy/Ch7/mlir/LowerToLLVM.cpp b/mlir/examples/toy/Ch7/mlir/LowerToLLVM.cpp
index a20a2c888a175..54eeb275ae85e 100644
--- a/mlir/examples/toy/Ch7/mlir/LowerToLLVM.cpp
+++ b/mlir/examples/toy/Ch7/mlir/LowerToLLVM.cpp
@@ -92,7 +92,7 @@ class PrintOpLowering : public ConversionPattern {
       auto step = rewriter.create<arith::ConstantIndexOp>(loc, 1);
       auto loop =
           rewriter.create<scf::ForOp>(loc, lowerBound, upperBound, step);
-      for (Operation &nested : *loop.getBody())
+      for (Operation &nested : make_early_inc_range(*loop.getBody()))
         rewriter.eraseOp(&nested);
       loopIvs.push_back(loop.getInductionVar());