diff --git a/thirdparty/README.md b/thirdparty/README.md
index e094422d7a..916fb2e0a7 100644
--- a/thirdparty/README.md
+++ b/thirdparty/README.md
@@ -952,7 +952,7 @@ Files extracted from upstream source:
 ## re-spirv
 
 - Upstream: https://github.com/renderbag/re-spirv
-- Version: git (ff2b1a506b0d4310702b5772fff901a626ffaaa1, 2026)
+- Version: git (29a77fca357567d00aa37b8ffde19c19cfe477c4, 2026)
 - License: MIT
 
 Files extracted from upstream source:
diff --git a/thirdparty/re-spirv/re-spirv.cpp b/thirdparty/re-spirv/re-spirv.cpp
index 7f3a246199..1734593139 100644
--- a/thirdparty/re-spirv/re-spirv.cpp
+++ b/thirdparty/re-spirv/re-spirv.cpp
@@ -2822,13 +2822,13 @@ namespace respv {
 
             if (terminatorReduced) {
                 // If there's a selection merge before this branch, we place the unconditional branch in its place.
-                const uint32_t mergeWordCount = 3;
-                uint32_t mergeWordIndex = wordIndex - mergeWordCount;
+                uint32_t mergeInstructionIndex = pInstructionIndex - 1;
+                uint32_t mergeWordIndex = rContext.shader.instructions[mergeInstructionIndex].wordIndex;
                 SpvOp mergeOpCode = SpvOp(optimizedWords[mergeWordIndex] & 0xFFFFU);
 
                 uint32_t patchWordIndex;
                 if (mergeOpCode == SpvOpSelectionMerge) {
-                    optimizerReduceLabelDegree(pInstructionIndex, optimizedWords[mergeWordIndex + 1], rContext);
+                    optimizerReduceLabelDegree(mergeInstructionIndex, optimizedWords[mergeWordIndex + 1], rContext);
                     patchWordIndex = mergeWordIndex;
                 }
                 else {