[llvm] AMDGPU: fix isSafeToSink expecting exactly one predecessor (PR #89224)

[Jay Foad via llvm-commits]

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@@ -217,10 +217,20 @@ bool SIInstrInfo::isSafeToSink(MachineInstr &MI,
         SmallVector<MachineBasicBlock *, 1> ExitBlocks;
         FromCycle->getExitBlocks(ExitBlocks);
         assert(ExitBlocks.size() == 1);
-        assert(ExitBlocks[0]->getSinglePredecessor());
-
+        // After structurize-cfg, cycle exit block should have exactly one
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jayfoad wrote:

Yes, if *this* code can easily handle arbitrary CFGs then it should do so.

If other parts of the code cannot handle arbitrary CFGs, then they should detect the problems.

https://github.com/llvm/llvm-project/pull/89224