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

[Ilia Diachkov via llvm-commits]

Nathan =?utf-8?q?Gauër?= <brioche at google.com>,
Nathan =?utf-8?q?Gauër?= <brioche at google.com>,
Nathan =?utf-8?q?Gauër?= <brioche at google.com>,
Nathan =?utf-8?q?Gauër?= <brioche at google.com>,
Nathan =?utf-8?q?Gauër?= <brioche at google.com>
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In-Reply-To: <llvm.org/llvm/llvm-project/pull/75844 at github.com>


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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.
+  // Thus, we can only trust negative result.
+  if (!MBB.canFallThrough())
+    return false;
+
+  // Otherwise, we must manually check if we have a spirv intrinsic which
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iliya-diyachkov wrote:

The same

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