From 09a39fac5dccf7ee68f6a24e2578740af498789b Mon Sep 17 00:00:00 2001
From: Elad <18193363+elad335@users.noreply.github.com>
Date: Tue, 30 Jun 2026 09:25:47 +0300
Subject: [PATCH] SPU LLVM: Discourage memory mirrors use on LQD/STQD

---
 rpcs3/Emu/Cell/SPULLVMRecompiler.cpp | 71 +++++++++++++++++-----------
 1 file changed, 44 insertions(+), 27 deletions(-)

diff --git a/rpcs3/Emu/Cell/SPULLVMRecompiler.cpp b/rpcs3/Emu/Cell/SPULLVMRecompiler.cpp
index 73396eb08a..b0c2c9854d 100644
--- a/rpcs3/Emu/Cell/SPULLVMRecompiler.cpp
+++ b/rpcs3/Emu/Cell/SPULLVMRecompiler.cpp
@@ -9288,6 +9288,11 @@ public:
 		return byteswap(data);
 	}
 
+	static constexpr u64 make_negative_LS_offset(u32 original)
+	{
+		return original | ~u64{SPU_LS_SIZE - 1};
+	}
+
 	void STQX(spu_opcode_t op)
 	{
 		const auto a = get_vr(op.ra);
@@ -9297,17 +9302,20 @@ public:
 		{
 			if (auto [ok, data] = get_const_vector(pair.first.value, m_pos); ok)
 			{
-				data._u32[3] %= SPU_LS_SIZE;
+				// "sign extend" offset addend
+				// Discourage the use of multiple addresses to refer to the same block of memory (due to memory mirrors use)
+				// Which may confuse LLVM's optimization
+				const u64 addend = (data._u32[3] >= SPU_LS_SIZE) ? make_negative_LS_offset(data._u32[3]) : data._u32[3];
 
 				if (const u32 remainder = data._u32[3] % 0x10; remainder == 0)
 				{
-					value_t<u64> addr = eval(splat<u64>(data._u32[3]) + zext<u64>(extract(pair.second, 3) & 0x3fff0));
+					value_t<u64> addr = eval(splat<u64>(addend) + zext<u64>(extract(pair.second, 3) & 0x3fff0));
 					make_store_ls(addr, get_vr<u8[16]>(op.rt));
 					return;
 				}
 				else
 				{
-					value_t<u64> addr = eval(splat<u64>(data._u32[3] - remainder) + zext<u64>((extract(pair.second, 3) + remainder) & 0x3fff0));
+					value_t<u64> addr = eval(splat<u64>(addend - remainder) + zext<u64>((extract(pair.second, 3) + remainder) & 0x3fff0));
 					make_store_ls(addr, get_vr<u8[16]>(op.rt));
 					return;
 				}
@@ -9327,17 +9335,20 @@ public:
 		{
 			if (auto [ok, data] = get_const_vector(pair.first.value, m_pos); ok)
 			{
-				data._u32[3] %= SPU_LS_SIZE;
+				// "sign extend" offset addend
+				// Discourage the use of multiple addresses to refer to the same block of memory
+				// Which may confuse LLVM's optimization
+				const u64 addend = (data._u32[3] >= SPU_LS_SIZE) ? make_negative_LS_offset(data._u32[3]) : data._u32[3];
 
 				if (const u32 remainder = data._u32[3] % 0x10; remainder == 0)
 				{
-					value_t<u64> addr = eval(splat<u64>(data._u32[3]) + zext<u64>(extract(pair.second, 3) & 0x3fff0));
+					value_t<u64> addr = eval(splat<u64>(addend) + zext<u64>(extract(pair.second, 3) & 0x3fff0));
 					set_vr(op.rt, make_load_ls(addr));
 					return;
 				}
 				else
 				{
-					value_t<u64> addr = eval(splat<u64>(data._u32[3] - remainder) + zext<u64>((extract(pair.second, 3) + remainder) & 0x3fff0));
+					value_t<u64> addr = eval(splat<u64>(addend - remainder) + zext<u64>((extract(pair.second, 3) + remainder) & 0x3fff0));
 					set_vr(op.rt, make_load_ls(addr));
 					return;
 				}
@@ -9398,18 +9409,22 @@ public:
 
 		if (auto [ok, x, y] = match_expr(a, match<u32[4]>() + match<u32[4]>()); ok)
 		{
-			if (auto [ok1, data] = get_const_vector(x.value, m_pos + 1); ok1 && data._u32[3] % 16 == 0)
+			for (auto pair : std::initializer_list<std::pair<llvm_match_t<u32[4]>, llvm_match_t<u32[4]>>>{{x, y}, {y, x}})
 			{
-				value_t<u64> addr = eval(zext<u64>(extract(y, 3) & 0x3fff0) + ((get_imm<u64>(op.si10) << 4) + splat<u64>(data._u32[3] & 0x3fff0)));
-				make_store_ls(addr, get_vr<u8[16]>(op.rt));
-				return;
-			}
+				if (auto [ok, data] = get_const_vector(pair.first.value, m_pos); ok)
+				{
+					// "sign extend" offset addend
+					// Discourage the use of multiple addresses to refer to the same block of memory
+					// Which may confuse LLVM's optimization
+					const u64 addend = (data._u32[3] >= SPU_LS_SIZE) ? make_negative_LS_offset(data._u32[3]) : data._u32[3];
 
-			if (auto [ok2, data] = get_const_vector(y.value, m_pos + 2); ok2 && data._u32[3] % 16 == 0)
-			{
-				value_t<u64> addr = eval(zext<u64>(extract(x, 3) & 0x3fff0) + ((get_imm<u64>(op.si10) << 4) + splat<u64>(data._u32[3] & 0x3fff0)));
-				make_store_ls(addr, get_vr<u8[16]>(op.rt));
-				return;
+					if (const u32 remainder = data._u32[3] % 0x10; remainder == 0)
+					{
+						value_t<u64> addr = eval(zext<u64>(extract(pair.second, 3) & 0x3fff0) + ((get_imm<u64>(op.si10) << 4) + splat<u64>(addend)));
+						make_store_ls(addr, get_vr<u8[16]>(op.rt));
+						return;
+					}
+				}
 			}
 		}
 
@@ -9421,20 +9436,22 @@ public:
 	{
 		const auto a = get_vr(op.ra);
 
-		if (auto [ok, x1, y1] = match_expr(a, match<u32[4]>() + match<u32[4]>()); ok)
+		if (auto [ok, x, y] = match_expr(a, match<u32[4]>() + match<u32[4]>()); ok)
 		{
-			if (auto [ok1, data] = get_const_vector(x1.value, m_pos + 1); ok1 && data._u32[3] % 16 == 0)
+			for (auto pair : std::initializer_list<std::pair<llvm_match_t<u32[4]>, llvm_match_t<u32[4]>>>{{x, y}, {y, x}})
 			{
-				value_t<u64> addr = eval(zext<u64>(extract(y1, 3) & 0x3fff0) + ((get_imm<u64>(op.si10) << 4) + splat<u64>(data._u32[3] & 0x3fff0)));
-				set_vr(op.rt, make_load_ls(addr));
-				return;
-			}
+				if (auto [ok, data] = get_const_vector(pair.first.value, m_pos); ok)
+				{
+					// "sign extend" offset addend
+					const u64 addend = (data._u32[3] >= SPU_LS_SIZE) ? data._u32[3] | ~u64{SPU_LS_SIZE - 1} : data._u32[3];
 
-			if (auto [ok2, data] = get_const_vector(y1.value, m_pos + 2); ok2 && data._u32[3] % 16 == 0)
-			{
-				value_t<u64> addr = eval(zext<u64>(extract(x1, 3) & 0x3fff0) + ((get_imm<u64>(op.si10) << 4) + splat<u64>(data._u32[3] & 0x3fff0)));
-				set_vr(op.rt, make_load_ls(addr));
-				return;
+					if (const u32 remainder = data._u32[3] % 0x10; remainder == 0)
+					{
+						value_t<u64> addr = eval(zext<u64>(extract(pair.second, 3) & 0x3fff0) + ((get_imm<u64>(op.si10) << 4) + splat<u64>(addend)));
+						set_vr(op.rt, make_load_ls(addr));
+						return;
+					}
+				}
 			}
 		}