Index: /home/seurer/llvm/llvm-test/projects/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace.h
===================================================================
--- /home/seurer/llvm/llvm-test/projects/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace.h
+++ /home/seurer/llvm/llvm-test/projects/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace.h
@@ -19,8 +19,7 @@
 
 static const u32 kStackTraceMax = 256;
 
-#if SANITIZER_LINUX && (defined(__aarch64__) || defined(__powerpc__) || \
-                        defined(__powerpc64__) || defined(__sparc__) || \
+#if SANITIZER_LINUX && (defined(__aarch64__) || defined(__sparc__) || \
                         defined(__mips__))
 # define SANITIZER_CAN_FAST_UNWIND 0
 #elif SANITIZER_WINDOWS
@@ -105,7 +104,7 @@
   void SlowUnwindStack(uptr pc, u32 max_depth);
   void SlowUnwindStackWithContext(uptr pc, void *context,
                                   u32 max_depth);
-  void PopStackFrames(uptr count);
+  void PopStackFramesToPC(uptr pc);
   uptr LocatePcInTrace(uptr pc);
 
   BufferedStackTrace(const BufferedStackTrace &);
Index: /home/seurer/llvm/llvm-test/projects/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace.cc
===================================================================
--- /home/seurer/llvm/llvm-test/projects/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace.cc
+++ /home/seurer/llvm/llvm-test/projects/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace.cc
@@ -17,6 +17,16 @@
 
 namespace __sanitizer {
 
+
+#if defined(__powerpc__) || defined(__powerpc64__)
+  static const int kOffsetToPcInFrame = 2;
+  static const bool kFastUnwindPopFramesToPC = true;
+#else
+  static const int kOffsetToPcInFrame = 1;
+  static const bool kFastUnwindPopFramesToPC = false;
+#endif
+
+
 uptr StackTrace::GetNextInstructionPc(uptr pc) {
 #if defined(__mips__)
   return pc + 8;
@@ -83,25 +93,39 @@
   while (IsValidFrame((uptr)frame, stack_top, bottom) &&
          IsAligned((uptr)frame, sizeof(*frame)) &&
          size < max_depth) {
-    uhwptr pc1 = frame[1];
+    uhwptr pc1 = frame[kOffsetToPcInFrame];
     if (pc1 != pc) {
       trace_buffer[size++] = (uptr) pc1;
     }
     bottom = (uptr)frame;
     frame = GetCanonicFrame((uptr)frame[0], stack_top, bottom);
   }
+  if (kFastUnwindPopFramesToPC) {
+    PopStackFramesToPC(pc);
+  }
 }
 
 static bool MatchPc(uptr cur_pc, uptr trace_pc, uptr threshold) {
   return cur_pc - trace_pc <= threshold || trace_pc - cur_pc <= threshold;
 }
 
-void BufferedStackTrace::PopStackFrames(uptr count) {
-  CHECK_LT(count, size);
-  size -= count;
+void BufferedStackTrace::PopStackFramesToPC(uptr pc) {
+  uptr to_pop = LocatePcInTrace(pc);
+  // trace_buffer[0] belongs to the current function so we always pop it,
+  // unless there is only 1 frame in the stack trace (1 frame is always better
+  // than 0!).
+  // 1-frame stacks don't normally happen, but this depends on the actual
+  // unwinder implementation (libgcc, libunwind, etc) which is outside of our
+  // control.
+  if (to_pop == 0 && size > 1)
+    to_pop = 1;
+
+  CHECK_LT(to_pop, size);
+  size -= to_pop;
   for (uptr i = 0; i < size; ++i) {
-    trace_buffer[i] = trace_buffer[i + count];
+    trace_buffer[i] = trace_buffer[i + to_pop];
   }
+  trace_buffer[0] = pc;
 }
 
 uptr BufferedStackTrace::LocatePcInTrace(uptr pc) {
Index: /home/seurer/llvm/llvm-test/projects/compiler-rt/lib/sanitizer_common/sanitizer_unwind_linux_libcdep.cc
===================================================================
--- /home/seurer/llvm/llvm-test/projects/compiler-rt/lib/sanitizer_common/sanitizer_unwind_linux_libcdep.cc
+++ /home/seurer/llvm/llvm-test/projects/compiler-rt/lib/sanitizer_common/sanitizer_unwind_linux_libcdep.cc
@@ -114,17 +114,7 @@
   UnwindTraceArg arg = {this, Min(max_depth + 1, kStackTraceMax)};
   _Unwind_Backtrace(Unwind_Trace, &arg);
   // We need to pop a few frames so that pc is on top.
-  uptr to_pop = LocatePcInTrace(pc);
-  // trace_buffer[0] belongs to the current function so we always pop it,
-  // unless there is only 1 frame in the stack trace (1 frame is always better
-  // than 0!).
-  // 1-frame stacks don't normally happen, but this depends on the actual
-  // unwinder implementation (libgcc, libunwind, etc) which is outside of our
-  // control.
-  if (to_pop == 0 && size > 1)
-    to_pop = 1;
-  PopStackFrames(to_pop);
-  trace_buffer[0] = pc;
+  PopStackFramesToPC(pc);
 }
 
 void BufferedStackTrace::SlowUnwindStackWithContext(uptr pc, void *context,
Index: /home/seurer/llvm/llvm-test/projects/compiler-rt/lib/sanitizer_common/sanitizer_unwind_posix_libcdep.cc
===================================================================
--- /home/seurer/llvm/llvm-test/projects/compiler-rt/lib/sanitizer_common/sanitizer_unwind_posix_libcdep.cc
+++ /home/seurer/llvm/llvm-test/projects/compiler-rt/lib/sanitizer_common/sanitizer_unwind_posix_libcdep.cc
@@ -113,18 +113,9 @@
   size = 0;
   UnwindTraceArg arg = {this, Min(max_depth + 1, kStackTraceMax)};
   _Unwind_Backtrace(Unwind_Trace, &arg);
+
   // We need to pop a few frames so that pc is on top.
-  uptr to_pop = LocatePcInTrace(pc);
-  // trace_buffer[0] belongs to the current function so we always pop it,
-  // unless there is only 1 frame in the stack trace (1 frame is always better
-  // than 0!).
-  // 1-frame stacks don't normally happen, but this depends on the actual
-  // unwinder implementation (libgcc, libunwind, etc) which is outside of our
-  // control.
-  if (to_pop == 0 && size > 1)
-    to_pop = 1;
-  PopStackFrames(to_pop);
-  trace_buffer[0] = pc;
+  PopStackFramesToPC(pc);
 }
 
 void BufferedStackTrace::SlowUnwindStackWithContext(uptr pc, void *context,