SPIRV Legalization fixes. (#3479)

* Fix CFG legalization for SPIRV backend.

* Emit DepthReplacing execution mode.

* Fix do-while lowering.

---------

Co-authored-by: Yong He <yhe@nvidia.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/tests/spirv/depth-replacing.slang b/tests/spirv/depth-replacing.slang
new file mode 100644
index 000000000..df2ab17e1
--- /dev/null
+++ b/tests/spirv/depth-replacing.slang
@@ -0,0 +1,16 @@
+//TEST:SIMPLE(filecheck=CHECK): -target spirv -stage fragment -entry main -emit-spirv-directly
+
+struct PSOut
+{
+    float4 color : SV_Target;
+    float depth : SV_Depth;
+}
+// CHECK: OpExecutionMode {{.*}} DepthReplacing
+
+PSOut main()
+{
+    PSOut psout;
+    psout.color = float4(1.0f, 0.0f, 0.0f, 1.0f);
+    psout.depth = 0.5f;
+    return psout;
+}