Index: llvm/trunk/lib/IR/LegacyPassManager.cpp
===================================================================
--- llvm/trunk/lib/IR/LegacyPassManager.cpp
+++ llvm/trunk/lib/IR/LegacyPassManager.cpp
@@ -545,7 +545,11 @@
     Timer *&T = TimingData[P];
     if (!T) {
       StringRef PassName = P->getPassName();
-      T = new Timer(PassName, PassName, TG);
+      StringRef PassArgument;
+      if (const PassInfo *PI = Pass::lookupPassInfo(P->getPassID()))
+        PassArgument = PI->getPassArgument();
+      T = new Timer(PassArgument.empty() ? PassName : PassArgument, PassName,
+                    TG);
     }
     return T;
   }
Index: llvm/trunk/test/CodeGen/X86/time-passes-json-stats.ll
===================================================================
--- llvm/trunk/test/CodeGen/X86/time-passes-json-stats.ll
+++ llvm/trunk/test/CodeGen/X86/time-passes-json-stats.ll
@@ -0,0 +1,14 @@
+; RUN: llc -mtriple=x86_64-- -stats-json=true -stats -time-passes %s -o /dev/null 2>&1 | FileCheck %s
+
+; Verify that we use the argument pass name instead of the full name as a json
+; key for timers.
+;
+; CHECK: {
+; CHECK-NEXT: "asm-printer.EmittedInsts":
+; CHECK-NOT: Virtual Register Map
+; CHECK: "time.pass.virtregmap.wall":
+; CHECK: "time.pass.virtregmap.user":
+; CHECK: "time.pass.virtregmap.sys":
+; CHECK: Virtual Register Map
+
+define void @test_stats() { ret void }