[Mlir-commits] [mlir] Avoid unnecessary erasing of constant Locs (PR #151573)

[llvmlistbot at llvm.org]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-mlir

Author: Majid Dadashi (majiddadashi)

<details>
<summary>Changes</summary>

Do not erase location info when moving an op within the same block.

This change avoids resetting the location of an operation when it is moved to the front of a block it is already in. The location is only reset when the operation is moved from a different block. END_PUBLIC

---
Full diff: https://github.com/llvm/llvm-project/pull/151573.diff


2 Files Affected:

- (modified) mlir/lib/Transforms/Utils/FoldUtils.cpp (+4-2) 
- (modified) mlir/test/Transforms/canonicalize-debuginfo.mlir (+4-4) 


``````````diff
diff --git a/mlir/lib/Transforms/Utils/FoldUtils.cpp b/mlir/lib/Transforms/Utils/FoldUtils.cpp
index e9adda0cd01db5..d22d697ac78df8 100644
--- a/mlir/lib/Transforms/Utils/FoldUtils.cpp
+++ b/mlir/lib/Transforms/Utils/FoldUtils.cpp
@@ -155,10 +155,12 @@ bool OperationFolder::insertKnownConstant(Operation *op, Attribute constValue) {
   // constant we unique'd (i.e. one we inserted), then we don't need to do
   // anything. Otherwise, we move the constant to the insertion block.
   Block *insertBlock = &insertRegion->front();
-  if (opBlock != insertBlock || (&insertBlock->front() != op &&
-                                 !isFolderOwnedConstant(op->getPrevNode()))) {
+  if (opBlock != insertBlock) {
     op->moveBefore(&insertBlock->front());
     op->setLoc(erasedFoldedLocation);
+  } else if (&insertBlock->front() != op &&
+             !isFolderOwnedConstant(op->getPrevNode())) {
+    op->moveBefore(&insertBlock->front());
   }
 
   folderConstOp = op;
diff --git a/mlir/test/Transforms/canonicalize-debuginfo.mlir b/mlir/test/Transforms/canonicalize-debuginfo.mlir
index 30c8022daa76b7..fc2b522e86f991 100644
--- a/mlir/test/Transforms/canonicalize-debuginfo.mlir
+++ b/mlir/test/Transforms/canonicalize-debuginfo.mlir
@@ -2,7 +2,7 @@
 
 // CHECK-LABEL: func @merge_constants
 func.func @merge_constants() -> (index, index, index, index) {
-  // CHECK-NEXT: arith.constant 42 : index loc(#[[UnknownLoc:.*]])
+  // CHECK: arith.constant 42 : index loc(#[[UnknownLoc:.*]])
   %0 = arith.constant 42 : index loc("merge_constants":0:0)
   %1 = arith.constant 42 : index loc("merge_constants":1:0)
   %2 = arith.constant 42 : index loc("merge_constants":2:0)
@@ -15,7 +15,7 @@ func.func @merge_constants() -> (index, index, index, index) {
 
 // CHECK-LABEL: func @simple_hoist
 func.func @simple_hoist(%arg0: memref<8xi32>) -> i32 {
-  // CHECK: arith.constant 88 : i32 loc(#[[UnknownLoc:.*]])
+  // CHECK: arith.constant 88 : i32 loc(#[[ConstLoc2:.*]])
   // CHECK: arith.constant 42 : i32 loc(#[[ConstLoc0:.*]])
   // CHECK: arith.constant 0 : index loc(#[[ConstLoc1:.*]])
   %0 = arith.constant 42 : i32 loc("simple_hoist":0:0)
@@ -26,15 +26,15 @@ func.func @simple_hoist(%arg0: memref<8xi32>) -> i32 {
 
   return %2 : i32
 }
-// CHECK-DAG: #[[UnknownLoc]] = loc(unknown)
 // CHECK-DAG: #[[ConstLoc0]] = loc("simple_hoist":0:0)
 // CHECK-DAG: #[[ConstLoc1]] = loc("simple_hoist":1:0)
+// CHECK-DAG: #[[ConstLoc2]] = loc("simple_hoist":2:0)
 
 // -----
 
 // CHECK-LABEL: func @hoist_and_merge
 func.func @hoist_and_merge(%arg0: memref<8xi32>) {
-  // CHECK-NEXT: arith.constant 42 : i32 loc(#[[UnknownLoc:.*]])
+  // CHECK: arith.constant 42 : i32 loc(#[[UnknownLoc:.*]])
   affine.for %arg1 = 0 to 8 {
     %0 = arith.constant 42 : i32 loc("hoist_and_merge":0:0)
     %1 = arith.constant 42 : i32 loc("hoist_and_merge":1:0)

``````````

</details>


https://github.com/llvm/llvm-project/pull/151573