[llvm] [SPIR-V] Add pre-headers to loops. (PR #75844)

[Nathan Gauër via llvm-commits]

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@@ -587,6 +587,40 @@ static void processSwitches(MachineFunction &MF, SPIRVGlobalRegistry *GR,
   }
 }
 
+static bool isImplicitFallthrough(MachineBasicBlock &MBB) {
+  if (MBB.empty())
+    return true;
+
+  // Branching spirv intrinsics are not detected by this generic method.
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Keenuts wrote:

Ah right, thanks! Fixed both occurences.

https://github.com/llvm/llvm-project/pull/75844