[llvm] Try To Guess SGMasks for Inline Asm Instructions (PR #155491)

Patrick Simmons via llvm-commits llvm-commits at lists.llvm.org
Mon Dec 22 13:11:53 PST 2025


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@@ -2391,6 +2391,56 @@ bool SchedGroup::canAddMI(const MachineInstr &MI) const {
   if (MI.isMetaInstruction())
     Result = false;
 
+  else if (MI.isInlineAsm()) {
+    const SIRegisterInfo &TRI = TII->getRegisterInfo();
+    auto &MRI = MI.getParent()->getParent()->getRegInfo();
+    bool SGPR_used = false, VGPR_used = false, VMFMA_used = false,
+         VReg32_used = false, MayLoad = MI.mayLoad(), MayStore = MI.mayStore();
+    for (const MachineOperand &Operand : MI.operands())
+      if (Operand.isReg()) {
+        auto &RegClass = *TRI.getRegClassForOperandReg(MRI, Operand);
+        if (TRI.hasVGPRs(&RegClass)) {
+          VGPR_used = true;
+          if (Operand.isUse() && TRI.getRegSizeInBits(RegClass) == 32)
+            VReg32_used = true;
+        }
+        // >= 128 bit registers are usually only used by MFMA instructions, so
+        // we're using that as a heuristic to guess the schedule group mask of
+        // the inline asm.
+        if (TRI.hasAGPRs(&RegClass) || TRI.getRegSizeInBits(RegClass) >= 128)
----------------
linuxrocks123 wrote:

Done

https://github.com/llvm/llvm-project/pull/155491


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