[llvm] [NVPTX] Add intrinsic support for specialized prmt variants (PR #140951)

[Alex MacLean via llvm-commits]

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@@ -745,9 +745,23 @@ class NVVMBuiltin :
 }
 
 let TargetPrefix = "nvvm" in {
-  def int_nvvm_prmt : NVVMBuiltin,
-      DefaultAttrsIntrinsic<[llvm_i32_ty], [llvm_i32_ty, llvm_i32_ty, llvm_i32_ty],
-        [IntrNoMem, IntrSpeculatable]>;
+
+  // PRMT - permute
+
+  let IntrProperties = [IntrNoMem, IntrSpeculatable] in {
+    def int_nvvm_prmt : NVVMBuiltin,
+      DefaultAttrsIntrinsic<[llvm_i32_ty], [llvm_i32_ty, llvm_i32_ty, llvm_i32_ty]>;
+
+    foreach mode = ["f4e", "b4e"] in
+      def int_nvvm_prmt_ # mode :
+          DefaultAttrsIntrinsic<[llvm_i32_ty], [llvm_i32_ty, llvm_i32_ty, llvm_i32_ty]>;
+
+    // Note: these variants also have 2 source operands but only one will ever
+    // be used so we eliminate the other operand in the IR.
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AlexMaclean wrote:

Sure, added!

https://github.com/llvm/llvm-project/pull/140951