[llvm] [AMDGPU] Fix illegal AGPR reclassification in RewriteMFMAFormStage (PR #200972)

[Dmitry Sidorov via llvm-commits]

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@@ -2263,6 +2264,23 @@ static bool isReachingDefAGPRForm(MachineInstr *RD,
   return false;
 }
 
+/// Returns true when \p Reg has a use that requires it to stay in VGPR form
+/// after the rewrite, i.e. any use other than a group MFMA.
+static bool
+src2RegEscapesRewriteGroup(Register Reg, const MachineRegisterInfo &MRI,
+                           const SmallPtrSetImpl<MachineInstr *> &RewriteSet,
+                           const SIInstrInfo &TII) {
+  for (const MachineOperand &Use : MRI.use_nodbg_operands(Reg)) {
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MrSidims wrote:

Sure, thanks!

https://github.com/llvm/llvm-project/pull/200972