[clang] [CIR] Add support for __builtin_alloca (PR #157116)

[Morris Hafner via cfe-commits]

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@@ -1053,9 +1053,12 @@ mlir::LogicalResult CIRToLLVMBaseClassAddrOpLowering::matchAndRewrite(
 mlir::LogicalResult CIRToLLVMAllocaOpLowering::matchAndRewrite(
     cir::AllocaOp op, OpAdaptor adaptor,
     mlir::ConversionPatternRewriter &rewriter) const {
-  assert(!cir::MissingFeatures::opAllocaDynAllocSize());
-  mlir::Value size = rewriter.create<mlir::LLVM::ConstantOp>(
-      op.getLoc(), typeConverter->convertType(rewriter.getIndexType()), 1);
+  mlir::Value size =
+      op.isDynamic() ? adaptor.getDynAllocSize()
+                     : rewriter.create<mlir::LLVM::ConstantOp>(
+                           op.getLoc(),
+                           typeConverter->convertType(rewriter.getIndexType()),
+                           rewriter.getIntegerAttr(rewriter.getIndexType(), 1));
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mmha wrote:

That was a copy paste error. I changed it back.

https://github.com/llvm/llvm-project/pull/157116