[llvm] [AArch64] Add streaming-mode stack hazards. (PR #98956)

[Eli Friedman via llvm-commits]

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@@ -3798,6 +3952,10 @@ bool AArch64FrameLowering::enableStackSlotScavenging(
   // function doesn't use a FP.
   if (AFI->hasStreamingModeChanges() && !hasFP(MF))
     return false;
+  // Don't allow register salvaging with hazard slots, in case it moves objects
+  // into the wrong place.
+  if (AFI->hasStackHazardSlotIndex())
+    return false;
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efriedma-quic wrote:

What's the interaction here?  Just that scavenging could introduce hazards?

https://github.com/llvm/llvm-project/pull/98956