[llvm] [AMDGPU] Improve isBasicBlockPrologue helper function (PR #69924)

[Christudasan Devadasan via llvm-commits]

================
@@ -8430,8 +8442,16 @@ unsigned SIInstrInfo::getLiveRangeSplitOpcode(Register SrcReg,
 }
 
 bool SIInstrInfo::isBasicBlockPrologue(const MachineInstr &MI) const {
-  return !MI.isTerminator() && MI.getOpcode() != AMDGPU::COPY &&
-         MI.modifiesRegister(AMDGPU::EXEC, &RI);
+  // It should cover all possible instructions (spills, copies, etc.) early
+  // inserted during RA in the block prolog to avoid the broken prologs that
----------------
cdevadas wrote:

Done

https://github.com/llvm/llvm-project/pull/69924