Implement context-sensitive expression read tracking.

When inside a loop, treat any read of outer expressions to happen
multiple times, forcing a temporary of said outer expressions.
This avoids the problem where we can end up relying on loop-invariant code motion to happen in the
compiler when converting optimized shaders.

1 files changed, 5 insertions, 0 deletions

diff --git a/spirv_cross.cpp b/spirv_cross.cpp
index 8abe19a4..19c9e1a9 100644
--- a/spirv_cross.cpp
+++ b/spirv_cross.cpp
@@ -4674,3 +4674,8 @@ bool Compiler::flush_phi_required(BlockID from, BlockID to) const
 			return true;
 	return false;
 }
+
+void Compiler::add_loop_level()
+{
+	current_loop_level++;
+}