[llvm] [AMDGPU] Adding multiple use analysis to SIPeepholeSDWA (PR #94800)

[Jay Foad via llvm-commits]

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@@ -327,7 +334,37 @@ uint64_t SDWASrcOperand::getSrcMods(const SIInstrInfo *TII,
   return Mods;
 }
 
-MachineInstr *SDWASrcOperand::potentialToConvert(const SIInstrInfo *TII) {
+MachineInstr *SDWASrcOperand::potentialToConvert(const SIInstrInfo *TII,
+                                                 const GCNSubtarget &ST,
+                                                 SDWAOperandsMap *PotentialMatches) {
+  // If PotentialMatches is not null, then fill out the map for all uses,
+  // if all can be converted
+  if (PotentialMatches != nullptr) {
+    MachineOperand *Reg = getReplacedOperand();
+    if (!Reg->isReg() || !Reg->isDef()) {
+      return nullptr;
+    }
+
+    for (MachineInstr &UseMI : getMRI()->use_nodbg_instructions(Reg->getReg())) {
+      // Check that all instructions that use Reg can be converted
+      if (!isConvertibleToSDWA(UseMI, ST, TII)) {
+        return nullptr;
+      }
+    }
+
+    // Now that it's guaranteed all uses are legal, iterate over the uses again
+    // to add them for later conversion.
+    for (MachineOperand &UseMO : getMRI()->use_nodbg_operands(Reg->getReg())) {
+      // Should not get a subregister here
+      assert(isSameReg(UseMO, *Reg));
+
+      SDWAOperandsMap& potentialMatchesMap = *PotentialMatches;
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jayfoad wrote:

If you have `clang/tools/clang-format/git-clang-format` on your path then you can run something like `git clang-format @^` to just reformat the code you touched in your most recent commit.

https://github.com/llvm/llvm-project/pull/94800