[clang] [HLSL][SPIR-V] Add `-fspv-enable-maximal-reconvergence` flag to clang dxc. (PR #163474)

[Steven Perron via cfe-commits]

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@@ -9600,6 +9600,15 @@ def fhlsl_spv_use_unknown_image_format
                "from the resource's data type.">,
       MarshallingInfoFlag<LangOpts<"HLSLSpvUseUnknownImageFormat">>;
 
+def fhlsl_spv_enable_maximal_reconvergence
+    : Flag<["-"], "fspv-enable-maximal-reconvergence">,
+      Group<dxc_Group>,
+      Visibility<[CC1Option, DXCOption]>,
+      HelpText<"Enables maximal reconvergence for SPIR-V codegen. This ensures "
+               "that all control flow merges at the nearest possible merge point "
+               "as defined by the Vulkan spec.">,
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s-perron wrote:

Update as above.

https://github.com/llvm/llvm-project/pull/163474