[Mlir-commits] [mlir] [mlir][tosa] Switch zero point of negate to input variable type (PR #129758)

[Luke Hutton]

================
@@ -1190,13 +1190,36 @@ OpFoldResult tosa::ExpOp::fold(FoldAdaptor adaptor) {
 }
 
 OpFoldResult tosa::NegateOp::fold(FoldAdaptor adaptor) {
-  auto input = getInput1();
   // Element-wise negate(negate(x)) = x
-  if (auto op = input.getDefiningOp<tosa::NegateOp>()) {
-    return op.getInput1();
+  // iff all zero points are constant 0
+  auto definingOp = getInput1().getDefiningOp<tosa::NegateOp>();
+  if (!definingOp) {
+    // defining op of input1 is not a negate, cannot fold
+    return {};
   }
 
-  return {};
+  if (FailureOr<int64_t> maybeIZp = getInput1ZeroPoint();
+      failed(maybeIZp) || *maybeIZp != 0) {
+    // input1 zero point is not constant 0, cannot fold
+    return {};
+  }
+  if (FailureOr<int64_t> maybeOZp = getOutputZeroPoint();
+      failed(maybeOZp) || *maybeOZp != 0) {
+    // output zero point is not constant 0, cannot fold
+    return {};
+  }
+  if (FailureOr<int64_t> maybeIZp = definingOp.getInput1ZeroPoint();
+      failed(maybeIZp) || *maybeIZp != 0) {
+    // definingOp's input1 zero point is not constant 0, cannot fold
+    return {};
+  }
+  if (FailureOr<int64_t> maybeOZp = definingOp.getOutputZeroPoint();
+      failed(maybeOZp) || *maybeOZp != 0) {
+    // definingOp's output zero point is not constant 0, cannot fold
+    return {};
+  }
----------------
lhutton1 wrote:

Can we also fold in the case when `input1ZeroPoint == definingOp.input1ZeroPoint && outputZeroPoint == definingOp.outputZeroPoint`? 

https://github.com/llvm/llvm-project/pull/129758