[llvm] [AMDGPU][wmma] - Add tied wmma intrinsic (PR #69903)

[Jay Foad via llvm-commits]

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@@ -865,22 +865,26 @@ def WMMAOpcode3AddrMappingTable : WMMAMappingTable {
 //    it converts the default pseudo to the pseudo where src2 is not the same as vdst.
 // 3) @earlyclobber on the destination satisfies the constraint during RA.
 
-multiclass WMMAInst<string Suffix, string Instr, VOPProfile P, SDPatternOperator node = null_frag, RegisterOperand _Src01RC64 = VRegSrc_256, WMMAType Type> {
+multiclass WMMAInst<string Suffix, string Instr, VOPProfile P, SDPatternOperator node = null_frag, RegisterOperand _Src01RC64 = VRegSrc_256, WMMAType Type, bit convertibleTo3Addr> {
 
   defvar WMMAConstraints2Addr = "@earlyclobber $vdst,$vdst = $src2";
   defvar WMMAConstraints3Addr = "@earlyclobber $vdst";
 
   defvar WMMAProfile = VOPProfileWMMA<P, Suffix, _Src01RC64, Type.hasClamp, Type.hasOpsel>;
   let Mnemonic = Instr, mayRaiseFPException = 0, ReadsModeReg = 0 in {
-    let Constraints = WMMAConstraints2Addr, isConvertibleToThreeAddress = 1 in {
+    let Constraints = WMMAConstraints2Addr, isConvertibleToThreeAddress = convertibleTo3Addr in {
       def _twoaddr # Suffix : VOP3P_Pseudo<Instr # Suffix, WMMAProfile>;
     }
-    let Constraints = WMMAConstraints3Addr, SchedRW = [Write32Bit, Write32Bit] in {
-      def _threeaddr # Suffix : VOP3P_Pseudo<Instr # Suffix, WMMAProfile>;
-    }
   }
-  def : WMMAOpcodeMapping<!cast<Instruction>(NAME # _twoaddr # Suffix),
+  if convertibleTo3Addr then {
+    let Mnemonic = Instr, mayRaiseFPException = 0, ReadsModeReg = 0 in {
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jayfoad wrote:

Nit: instead of repeating this "let" clause here, I think it would be neater to put this new code inside the existing "let" clause, i.e. move it up to just before the closing brace on line 878.

Yes this will mean that the "let" clause now applies to the WMMAOpcodeMapping part too, but that should be harmless.

https://github.com/llvm/llvm-project/pull/69903