DSPAnalyzer: Disable update SR analysis

It doesn't work right in all situations, including in the cond_test hardware test.  It could definitely be fixed, but it would be a hassle to do so.

Source/Core/Core/DSP/DSPAnalyzer.cpp

@@ -91,7 +91,9 @@ void Analyzer::FindInstructionStarts(const SDSP& dsp, u16 start_addr, u16 end_ad
 {
   // This may not be 100% accurate in case of jump tables!
   // It could get desynced, which would be bad. We'll see if that's an issue.
+#ifndef DISABLE_UPDATE_SR_ANALYSIS
   u16 last_arithmetic = 0;
+#endif
   for (u16 addr = start_addr; addr < end_addr;)
   {
     const UDSPInstruction inst = dsp.ReadIMEM(addr);
@@ -117,6 +119,7 @@ void Analyzer::FindInstructionStarts(const SDSP& dsp, u16 start_addr, u16 end_ad
       m_code_flags[static_cast<u16>(addr + 1u)] |= CODE_LOOP_END;
     }
 
+#ifndef DISABLE_UPDATE_SR_ANALYSIS
     // Mark the last arithmetic/multiplier instruction before a branch.
     // We must update the SR reg at these instructions
     if (opcode->updates_sr)
@@ -128,6 +131,7 @@ void Analyzer::FindInstructionStarts(const SDSP& dsp, u16 start_addr, u16 end_ad
     {
       m_code_flags[last_arithmetic] |= CODE_UPDATE_SR;
     }
+#endif
 
     // If an instruction potentially raises exceptions, mark the following
     // instruction as needing to check for exceptions

Source/Core/Core/DSP/DSPAnalyzer.h

@@ -6,6 +6,13 @@
 #include <array>
 #include "Common/CommonTypes.h"
 
+// The update SR analysis is not perfect: it does not properly handle modified SR values if SR is
+// only read within a function call, and it's possible that a previous instruction sets SR (e.g. the
+// logical zero bit, or the sticky overflow bit) but is marked as not changing SR as a later
+// instruction sets it.  When this flag is set, we always treat instructions as updating SR, and
+// disable the analysis for if SR needs to be set.
+#define DISABLE_UPDATE_SR_ANALYSIS
+
 namespace DSP
 {
 struct SDSP;
@@ -63,7 +70,11 @@ public:
   // Whether or not the address describes an instruction that requires updating the SR register.
   [[nodiscard]] bool IsUpdateSR(u16 address) const
   {
+#ifdef DISABLE_UPDATE_SR_ANALYSIS
+    return true;
+#else
     return (GetCodeFlags(address) & CODE_UPDATE_SR) != 0;
+#endif
   }
 
   // Whether or not the address describes instructions that potentially raise exceptions.