From 2003890a48684d64384e5c66bc28836a3f15aa0f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Henrik=20Rydg=C3=A5rd?= <hrydgard@gmail.com>
Date: Mon, 2 May 2022 08:50:42 +0200
Subject: [PATCH] Hackery to help track down #15149. Runs without breaking on
 PC.

---
 Core/MIPS/MIPSIntVFPU.cpp   |  4 ++--
 Core/MIPS/MIPSVFPUUtils.cpp | 12 +++++++++++-
 Core/MIPS/MIPSVFPUUtils.h   |  2 +-
 3 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/Core/MIPS/MIPSIntVFPU.cpp b/Core/MIPS/MIPSIntVFPU.cpp
index 8f761b858d..13bb9b052d 100644
--- a/Core/MIPS/MIPSIntVFPU.cpp
+++ b/Core/MIPS/MIPSIntVFPU.cpp
@@ -235,7 +235,7 @@ namespace MIPSInt
 						d[i] = Memory::Read_Float(addr + 4 * i);
 					}
 				}
-				WriteVector(d, V_Quad, vt);
+				WriteVector(d, V_Quad, vt, true);
 			}
 			break;
 
@@ -247,7 +247,7 @@ namespace MIPSInt
 #ifndef COMMON_BIG_ENDIAN
 			f = reinterpret_cast<float *>(Memory::GetPointer(addr));
 			if (f)
-				WriteVector(f, V_Quad, vt);
+				WriteVector(f, V_Quad, vt, true);
 #else
 			float lvqd[4];
 
diff --git a/Core/MIPS/MIPSVFPUUtils.cpp b/Core/MIPS/MIPSVFPUUtils.cpp
index 0f1d6688ab..723986da5a 100644
--- a/Core/MIPS/MIPSVFPUUtils.cpp
+++ b/Core/MIPS/MIPSVFPUUtils.cpp
@@ -22,6 +22,7 @@
 
 #include "Common/BitScan.h"
 #include "Common/CommonFuncs.h"
+#include "Common/Math/math_util.h"
 #include "Core/Reporting.h"
 #include "Core/MIPS/MIPS.h"
 #include "Core/MIPS/MIPSVFPUUtils.h"
@@ -183,7 +184,7 @@ void ReadVector(float *rd, VectorSize size, int reg) {
 	}
 }
 
-void WriteVector(const float *rd, VectorSize size, int reg) {
+void WriteVector(const float *rd, VectorSize size, int reg, bool is_svq) {
 	if (size == V_Single) {
 		// Optimize the common case.
 		if (!currentMIPS->VfpuWriteMask(0)) {
@@ -206,6 +207,15 @@ void WriteVector(const float *rd, VectorSize size, int reg) {
 	default: _assert_msg_(false, "%s: Bad vector size", __FUNCTION__);
 	}
 
+	// TEMP HACK for issue #15149
+	// There's often garbage in the fourth coordinate so ignore it.
+	// Additionally, the SVQ instruction specifically stores some NaN data.
+	for (int i = 0; i < std::min(length, 3); i++) {
+		if (my_isnan(rd[i]) && !is_svq) {
+			DebugBreak();
+		}
+	}
+
 	if (currentMIPS->VfpuWriteMask() == 0) {
 		if (transpose) {
 			const int base = mtx * 4 + col * 32;
diff --git a/Core/MIPS/MIPSVFPUUtils.h b/Core/MIPS/MIPSVFPUUtils.h
index df1a1b85b0..1bd3424c2a 100644
--- a/Core/MIPS/MIPSVFPUUtils.h
+++ b/Core/MIPS/MIPSVFPUUtils.h
@@ -150,7 +150,7 @@ u32 VFPURewritePrefix(int ctrl, u32 remove, u32 add);
 void ReadMatrix(float *rd, MatrixSize size, int reg);
 void WriteMatrix(const float *rs, MatrixSize size, int reg);
 
-void WriteVector(const float *rs, VectorSize N, int reg);
+void WriteVector(const float *rs, VectorSize N, int reg, bool is_svq = false);
 void ReadVector(float *rd, VectorSize N, int reg);
 
 void GetVectorRegs(u8 regs[4], VectorSize N, int vectorReg);