[clang] [llvm] [SPIR-V] Generate SPIR-V instructions when 'enable-maximal-reconvergence' function attribute is set (PR #163682)

[Steven Perron via cfe-commits]

================
@@ -0,0 +1,20 @@
+; RUN: llc -O0 -verify-machineinstrs -mtriple=spirv1.6-unknown-vulkan1.3-compute --spirv-ext=+SPV_KHR_maximal_reconvergence %s -o - | FileCheck %s
+; RUN: %if spirv-tools %{ llc -O0 -mtriple=spirv1.6-unknown-vulkan1.3-compute --spirv-ext=+SPV_KHR_maximal_reconvergence %s -o - -filetype=obj | spirv-val %}
+
+; CHECK: OpCapability Shader
+; CHECK: OpExtension "SPV_KHR_maximal_reconvergence"
+; CHECK-NOT: OpExtension "SPV_KHR_maximal_reconvergence"
+; CHECK: OpExecutionMode {{.*}} MaximallyReconvergesKHR
+; CHECK-NOT: OpExecutionMode {{.*}} MaximallyReconvergesKHR
----------------
s-perron wrote:

This way you are not checking that main is the function with the execution mode. You might need to make is more specific.

https://github.com/llvm/llvm-project/pull/163682