From 5fdcd571cd37a3996b6479e43a10eaecaa9b3295 Mon Sep 17 00:00:00 2001
From: Pacuka <69674426+Pacuka@users.noreply.github.com>
Date: Sun, 27 Sep 2026 18:59:46 +0200
Subject: [PATCH] fix(recompiler): widen constants of 64-bit operands instead
 of repeating them

readU32Pair read a literal or inline constant into both halves of a 64-bit
source. A literal is now zero-extended, an integer inline constant
sign-extended and a float inline constant becomes the matching double.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 .../src/TranslationContext/SubwordPacking.cpp        | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/core/shader/recompiler/Translation/src/TranslationContext/SubwordPacking.cpp b/core/shader/recompiler/Translation/src/TranslationContext/SubwordPacking.cpp
index e1ba9818f..d8b32b7e0 100644
--- a/core/shader/recompiler/Translation/src/TranslationContext/SubwordPacking.cpp
+++ b/core/shader/recompiler/Translation/src/TranslationContext/SubwordPacking.cpp
@@ -1,5 +1,7 @@
 #include "Translation/TranslationContext.hpp"
 #include <array>
+#include <bit>
+#include <cstdint>
 
 namespace ShaderRecompiler {
 
@@ -8,7 +10,15 @@ IrU32 TranslationContext::readU32(const RdnaOperand& operand) {
 }
 
 std::array<IrU32, 2> TranslationContext::readU32Pair(const RdnaOperand& operand) {
-    return {readU32(operand), readU32(offsetOperand(operand, 1u))};
+    switch (operand.kind) {
+        case RdnaOperandKind::LiteralConstant: return {readU32(operand), IrU32(ir.Constant(0u))};
+        case RdnaOperandKind::IntegerInlineConstant: return {readU32(operand), IrU32(ir.Constant(operand.signedVal < 0 ? 0xffffffffu : 0u))};
+        case RdnaOperandKind::FloatInlineConstant: {
+            const auto bits = std::bit_cast<std::uint64_t>(static_cast<double>(std::bit_cast<float>(operand.value)));
+            return {IrU32(ir.Constant(static_cast<std::uint32_t>(bits))), IrU32(ir.Constant(static_cast<std::uint32_t>(bits >> 32u)))};
+        }
+        default: return {readU32(operand), readU32(offsetOperand(operand, 1u))};
+    }
 }
 
 IrU64 TranslationContext::readU64(const RdnaOperand& operand) {