1 files changed, 18 insertions, 5 deletions
diff --git a/llvm/lib/CodeGen/GlobalISel/CSEInfo.cpp b/llvm/lib/CodeGen/GlobalISel/CSEInfo.cpp
index 2fa208fbfaaf..f9bfe8518083 100644
--- a/llvm/lib/CodeGen/GlobalISel/CSEInfo.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/CSEInfo.cpp
@@ -11,6 +11,7 @@
 #include "llvm/CodeGen/GlobalISel/CSEInfo.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/InitializePasses.h"
+#include "llvm/Support/Error.h"
 
 #define DEBUG_TYPE "cseinfo"
 
@@ -259,8 +260,17 @@ void GISelCSEInfo::releaseMemory() {
 #endif
 }
 
+#ifndef NDEBUG
+static const char *stringify(const MachineInstr *MI, std::string &S) {
+  raw_string_ostream OS(S);
+  OS << *MI;
+  return OS.str().c_str();
+}
+#endif
+
 Error GISelCSEInfo::verify() {
 #ifndef NDEBUG
+  std::string S1, S2;
   handleRecordedInsts();
   // For each instruction in map from MI -> UMI,
   // Profile(MI) and make sure UMI is found for that profile.
@@ -273,20 +283,23 @@ Error GISelCSEInfo::verify() {
     if (FoundNode != It.second)
       return createStringError(std::errc::not_supported,
                                "CSEMap mismatch, InstrMapping has MIs without "
-                               "corresponding Nodes in CSEMap");
+                               "corresponding Nodes in CSEMap:\n%s",
+                               stringify(It.second->MI, S1));
   }
 
   // For every node in the CSEMap, make sure that the InstrMapping
   // points to it.
-  for (auto It = CSEMap.begin(), End = CSEMap.end(); It != End; ++It) {
-    const UniqueMachineInstr &UMI = *It;
+  for (const UniqueMachineInstr &UMI : CSEMap) {
     if (!InstrMapping.count(UMI.MI))
       return createStringError(std::errc::not_supported,
-                               "Node in CSE without InstrMapping", UMI.MI);
+                               "Node in CSE without InstrMapping:\n%s",
+                               stringify(UMI.MI, S1));
 
     if (InstrMapping[UMI.MI] != &UMI)
       return createStringError(std::make_error_code(std::errc::not_supported),
-                               "Mismatch in CSE mapping");
+                               "Mismatch in CSE mapping:\n%s\n%s",
+                               stringify(InstrMapping[UMI.MI]->MI, S1),
+                               stringify(UMI.MI, S2));
   }
 #endif
   return Error::success();