[Mlir-commits] [mlir] [mlir][AMDGPU] Add better load/store lowering for full select mask (PR #146748)

[Kunwar Grover]

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@@ -61,6 +61,36 @@ static Value createVectorLoadForMaskedLoad(OpBuilder &builder, Location loc,
   return res;
 }
 
+/// Check if the given value comes from a:
+///
+/// arith.select %cond, TRUE/FALSE, TRUE/FALSE
+///
+/// i.e the condition is either always true or it's always false.
+///
+/// Returns the condition to use for scf.if (condition) { true } else { false }.
+static FailureOr<Value> matchFullSelect(OpBuilder &b, Value val) {
+  auto selectOp = val.getDefiningOp<arith::SelectOp>();
+  if (!selectOp)
+    return failure();
+  std::optional<int64_t> trueInt = getConstantIntValue(selectOp.getTrueValue());
+  std::optional<int64_t> falseInt =
+      getConstantIntValue(selectOp.getFalseValue());
+  if (!trueInt || !falseInt)
+    return failure();
+  // getConstantIntValue returns -1 for "true" for bools.
+  if (trueInt.value() == -1 && falseInt.value() == 0)
+    return selectOp.getCondition();
+
+  if (trueInt.value() == 0 && falseInt.value() == -1) {
+    Value cond = selectOp.getCondition();
+    Value one = b.create<arith::ConstantIntOp>(cond.getLoc(), /*value=*/true,
+                                               /*width=*/1);
+    Value inverse = b.create<arith::XOrIOp>(cond.getLoc(), cond, one);
+    return inverse;
+  }
+  return failure();
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Groverkss wrote:

not needed anymore

https://github.com/llvm/llvm-project/pull/146748