[llvm] [AMDGPU] Check noalias.addrspace in mayAccessScratchThroughFlat (PR #151319)

[Shilei Tian via llvm-commits]

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@@ -4249,6 +4249,24 @@ bool SIInstrInfo::isAlwaysGDS(uint16_t Opcode) const {
          Opcode == AMDGPU::DS_SUB_GS_REG_RTN || isGWS(Opcode);
 }
 
+static bool hasNoAliasAddrSpaceScratch(const MachineMemOperand *MemOp) {
+  const MDNode *MD = MemOp->getAAInfo().NoAliasAddrSpace;
+  if (!MD)
+    return false;
+
+  // This MD is structured in ranges [A, B)
+  // Check if PRIVATE is included in any of them.
+  for (unsigned I = 0, E = MD->getNumOperands() / 2; I != E; ++I) {
+    auto *Low = mdconst::extract<ConstantInt>(MD->getOperand(2 * I + 0));
+    auto *High = mdconst::extract<ConstantInt>(MD->getOperand(2 * I + 1));
+    if (Low->getValue().ule(AMDGPUAS::PRIVATE_ADDRESS) &&
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shiltian wrote:

Check null before use

https://github.com/llvm/llvm-project/pull/151319