From 6e7b9423ad72714f72300a7c479da86624ae7eed Mon Sep 17 00:00:00 2001
From: Tim Besard <tim.besard@gmail.com>
Date: Tue, 3 Nov 2026 14:12:35 +0100
Subject: [PATCH] Check that flattened insertvalues reach the SPIR-V back end

The comment on `flatten_nested_insertvalue!` said it has to run after
optimization because InstCombine folds the flattened sequences back
together. InstCombine also runs after `finish_ir!`, in
`prepare_execution!`, so that would undo the Intel workaround. It
doesn't: InstCombine never merges single-index `insertvalue`s into
multi-index ones, and it is SROA, during optimization, that introduces
those. Correct the comment, and test the SPIR-V instead of only the
`finish_ir!` output, so that a pass added later between the two can't
undo the workaround unnoticed.
---
 src/spirv.jl  | 4 +++-
 test/spirv.jl | 8 ++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/spirv.jl b/src/spirv.jl
index b5156f47..1e1912eb 100644
--- a/src/spirv.jl
+++ b/src/spirv.jl
@@ -937,7 +937,9 @@ end
 # indices than the field it is looking for, silently dropping the store of that field.
 # e.g., storing `(flag::Bool, (a, b))` built by inserting `flag`, `a` and `b`, loses `flag`
 # (intel/intel-graphics-compiler#378, JuliaGPU/OpenCL.jl#502, JuliaGPU/oneAPI.jl#259).
-# this needs to run after optimization, as InstCombine folds these sequences back together.
+# this runs after optimization, where SROA introduces these `insertvalue`s when splitting
+# aggregate loads. the InstCombine run in `prepare_execution!` doesn't reconstruct them
+# from the flattened form.
 function flatten_nested_insertvalue!(mod::LLVM.Module)
     changed = false
     @tracepoint "flatten nested insertvalue" begin
diff --git a/test/spirv.jl b/test/spirv.jl
index 35e09f0e..61e24dd5 100644
--- a/test/spirv.jl
+++ b/test/spirv.jl
@@ -286,6 +286,14 @@ end
         @check "insertvalue {{.*}}, 1"
         SPIRV.code_llvm(mod.kernel, tt; backend, driver=:intel)
     end
+
+    # the flattened form must survive the passes that run between `finish_ir!` and the
+    # back end (`prepare_execution!` runs InstCombine)
+    @test @filecheck begin
+        @check "OpFunction"
+        @check_not "OpCompositeInsert {{.*}} {{[0-9]+}} {{[0-9]+}}{{\$}}"
+        SPIRV.code_native(mod.kernel, tt; backend, driver=:intel)
+    end
 end
 
 ############################################################################################