[llvm] Spill/restore FP/BP around instructions in which they are clobbered (PR #81048)

[via llvm-commits]

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@@ -77,6 +77,15 @@ using MBBVector = SmallVector<MachineBasicBlock *, 4>;
 STATISTIC(NumLeafFuncWithSpills, "Number of leaf functions with CSRs");
 STATISTIC(NumFuncSeen, "Number of functions seen in PEI");
 
+static cl::opt<bool>
+    SpillClobberedFP("spill-clobbered-fp",
+                     cl::desc("Spill clobbered fp register to stack."),
+                     cl::init(false), cl::Hidden);
+
+static cl::opt<bool>
+    SpillClobberedBP("spill-clobbered-bp",
+                     cl::desc("Spill clobbered bp register to stack."),
+                     cl::init(true), cl::Hidden);
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zmodem wrote:

I don't see why we'd need flags for this?

https://github.com/llvm/llvm-project/pull/81048