[flang-commits] [flang] [mlir] [MLIR] Add cpow support in ComplexToROCDLLibraryCalls (PR #153183)

[Krzysztof Drewniak via flang-commits]

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@@ -56,10 +56,43 @@ struct ComplexOpToROCDLLibraryCalls : public OpRewritePattern<Op> {
 private:
   std::string funcName;
 };
+
+// Rewrite complex.pow(z, w) -> complex.exp(w * complex.log(z))
+struct PowOpToROCDLLibraryCalls : public OpRewritePattern<complex::PowOp> {
+  using OpRewritePattern<complex::PowOp>::OpRewritePattern;
+
+  LogicalResult matchAndRewrite(complex::PowOp op,
+                                PatternRewriter &rewriter) const final {
+    auto loc = op.getLoc();
+    if (auto constOp = op.getRhs().getDefiningOp<complex::ConstantOp>()) {
+      ArrayAttr value = constOp.getValue();
+      if (value.size() == 2) {
+        auto real = dyn_cast<FloatAttr>(value[0]);
+        auto imag = dyn_cast<FloatAttr>(value[1]);
+        if (real && imag && imag.getValue().isZero())
+          for (int i = 2; i <= 8; ++i)
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krzysz00 wrote:

In other words, this is a _lowering_ pass, the optimization you're doing here isn't actually that AMDGPU-specific, and so it shouldn't be here

https://github.com/llvm/llvm-project/pull/153183