[Mlir-commits] [mlir] 6937dbb - [mlir][memref] Fix `alloca` lowering with 0 dimensions (#111119)

[llvmlistbot at llvm.org]

Author: Matthias Springer
Date: 2024-10-04T17:32:31+02:00
New Revision: 6937dbbe51391471f3cf50fe2b8fa2cd14080a3b

URL: https://github.com/llvm/llvm-project/commit/6937dbbe51391471f3cf50fe2b8fa2cd14080a3b
DIFF: https://github.com/llvm/llvm-project/commit/6937dbbe51391471f3cf50fe2b8fa2cd14080a3b.diff

LOG: [mlir][memref] Fix `alloca` lowering with 0 dimensions (#111119)

The `memref.alloca` lowering computed the allocation size incorrectly
when there were 0 dimensions.

Previously:
```
memref.alloca() : memref<10x0x2xf32>
--> llvm.alloca 20xf32
```

Now:
```
memref.alloca() : memref<10x0x2xf32>
--> llvm.alloca 0xf32
```

>From the `llvm.alloca` documentation:
```
Allocating zero bytes is legal, but the returned pointer may not be unique.
```

Added: 
    

Modified: 
    mlir/lib/Conversion/LLVMCommon/Pattern.cpp
    mlir/test/Conversion/MemRefToLLVM/convert-static-memref-ops.mlir

Removed: 
    


################################################################################
diff  --git a/mlir/lib/Conversion/LLVMCommon/Pattern.cpp b/mlir/lib/Conversion/LLVMCommon/Pattern.cpp
index 1886dfa870961a..d551506485a454 100644
--- a/mlir/lib/Conversion/LLVMCommon/Pattern.cpp
+++ b/mlir/lib/Conversion/LLVMCommon/Pattern.cpp
@@ -139,8 +139,6 @@ void ConvertToLLVMPattern::getMemRefDescriptorSizes(
     strides[i] = runningStride;
 
     int64_t staticSize = memRefType.getShape()[i];
-    if (staticSize == 0)
-      continue;
     bool useSizeAsStride = stride == 1;
     if (staticSize == ShapedType::kDynamic)
       stride = ShapedType::kDynamic;

diff  --git a/mlir/test/Conversion/MemRefToLLVM/convert-static-memref-ops.mlir b/mlir/test/Conversion/MemRefToLLVM/convert-static-memref-ops.mlir
index 96cf2264e9c2f3..4f4ce0d0ed978e 100644
--- a/mlir/test/Conversion/MemRefToLLVM/convert-static-memref-ops.mlir
+++ b/mlir/test/Conversion/MemRefToLLVM/convert-static-memref-ops.mlir
@@ -95,6 +95,22 @@ func.func @static_alloca() -> memref<32x18xf32> {
 
 // -----
 
+// CHECK-LABEL: func @static_alloca_zero()
+func.func @static_alloca_zero() -> memref<32x0x18xf32> {
+// CHECK: %[[sz1:.*]] = llvm.mlir.constant(32 : index) : i64
+// CHECK: %[[sz2:.*]] = llvm.mlir.constant(0 : index) : i64
+// CHECK: %[[sz3:.*]] = llvm.mlir.constant(18 : index) : i64
+// CHECK: %[[st1:.*]] = llvm.mlir.constant(1 : index) : i64
+// CHECK: %[[st2:.*]] = llvm.mlir.constant(0 : index) : i64
+// CHECK: %[[num_elems:.*]] = llvm.mlir.constant(0 : index) : i64
+// CHECK: %[[allocated:.*]] = llvm.alloca %[[num_elems]] x f32 : (i64) -> !llvm.ptr
+ %0 = memref.alloca() : memref<32x0x18xf32>
+
+ return %0 : memref<32x0x18xf32>
+}
+
+// -----
+
 // CHECK-LABEL: func @static_dealloc
 func.func @static_dealloc(%static: memref<10x8xf32>) {
 // CHECK: %[[ptr:.*]] = llvm.extractvalue %{{.*}}[0] : !llvm.struct<(ptr, ptr, i64, array<2 x i64>, array<2 x i64>)>