[Mlir-commits] [mlir] [mlir][amdgpu] lowerings for ScaledExtPacked816 (PR #168123)

[Erick Ochoa Lopez]

================
@@ -1600,6 +1613,182 @@ LogicalResult ExtPackedFp8OpLowering::matchAndRewrite(
   return success();
 }
 
+int getScaleSel(int blockSize, int bitWidth, int firstScaleLane,
+                int firstScaleByte) {
+  // When lowering amdgpu.scaled_ext_packed816 to
+  // rocdl.cvt.scale.pk*.f*.f* operations, the
+  // attributes blockSize, sourceType, firstScaleLane and firstScaleByte
+  // are merged into a single attribute scaleSel.
+  //
+  // This is how those values are merged together.
+  assert(llvm::is_contained({16, 32}, blockSize));
+  assert(llvm::is_contained({4, 6, 8}, bitWidth));
+
+  const bool is_fp8 = bitWidth == 8;
+  const bool is_block_16 = blockSize == 16;
+
+  if (!is_fp8 && firstScaleLane == 0 && firstScaleByte == 0 && !is_block_16) {
+    return 0b000;
+  }
+  if (!is_fp8 && firstScaleLane == 0 && firstScaleByte == 0 && is_block_16) {
+    return 0b001;
+  }
+  if (!is_fp8 && firstScaleLane == 0 && firstScaleByte == 2 && !is_block_16) {
+    return 0b010;
+  }
+  if (!is_fp8 && firstScaleLane == 0 && firstScaleByte == 2 && is_block_16) {
+    return 0b011;
+  }
+  if (!is_fp8 && firstScaleLane == 1 && firstScaleByte == 0 && !is_block_16) {
+    return 0b100;
+  }
+  if (!is_fp8 && firstScaleLane == 1 && firstScaleByte == 0 && is_block_16) {
+    return 0b101;
+  }
+  if (!is_fp8 && firstScaleLane == 1 && firstScaleByte == 2 && !is_block_16) {
+    return 0b110;
+  }
+  if (!is_fp8 && firstScaleLane == 1 && firstScaleByte == 2 && is_block_16) {
+    return 0b111;
+  }
+
+  if (is_fp8 && firstScaleLane == 0 && firstScaleByte == 0 && !is_block_16) {
+    return 0b0000;
+  }
+  if (is_fp8 && firstScaleLane == 0 && firstScaleByte == 0 && is_block_16) {
+    return 0b0001;
+  }
+  if (is_fp8 && firstScaleLane == 0 && firstScaleByte == 1 && !is_block_16) {
+    return 0b0010;
+  }
+  if (is_fp8 && firstScaleLane == 0 && firstScaleByte == 2 && !is_block_16) {
+    return 0b0100;
+  }
+  if (is_fp8 && firstScaleLane == 0 && firstScaleByte == 3 && !is_block_16) {
+    return 0b0110;
+  }
+  if (is_fp8 && firstScaleLane == 1 && firstScaleByte == 1 && !is_block_16) {
+    return 0b1010;
+  }
+  if (is_fp8 && firstScaleLane == 1 && firstScaleByte == 2 && !is_block_16) {
+    return 0b1100;
+  }
+  if (is_fp8 && firstScaleLane == 1 && firstScaleByte == 2 && is_block_16) {
+    return 0b1101;
+  }
+  if (is_fp8 && firstScaleLane == 1 && firstScaleByte == 3 && !is_block_16) {
----------------
amd-eochoalo wrote:

https://github.com/llvm/llvm-project/pull/168123/commits/2b010cd04d4644b06a864777de0c63edae4be0c6

https://github.com/llvm/llvm-project/pull/168123