diff --git a/llvm/lib/Target/SystemZ/SystemZInstrInfo.cpp b/llvm/lib/Target/SystemZ/SystemZInstrInfo.cpp
index b4c5afc5c1a4..214b9291167e 100644
--- a/llvm/lib/Target/SystemZ/SystemZInstrInfo.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZInstrInfo.cpp
@@ -27,6 +27,7 @@
 #include "llvm/CodeGen/MachineOperand.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/CodeGen/SlotIndexes.h"
+#include "llvm/CodeGen/StackMaps.h"
 #include "llvm/CodeGen/TargetInstrInfo.h"
 #include "llvm/CodeGen/TargetSubtargetInfo.h"
 #include "llvm/MC/MCInstrDesc.h"
@@ -1515,6 +1516,13 @@ unsigned SystemZInstrInfo::getInstSizeInBytes(const MachineInstr &MI) const {
     const char *AsmStr = MI.getOperand(0).getSymbolName();
     return getInlineAsmLength(AsmStr, *MF->getTarget().getMCAsmInfo());
   }
+  else if (MI.getOpcode() == SystemZ::PATCHPOINT)
+    return PatchPointOpers(&MI).getNumPatchBytes();
+  else if (MI.getOpcode() == SystemZ::STACKMAP)
+    return MI.getOperand(1).getImm();
+  else if (MI.getOpcode() == SystemZ::FENTRY_CALL)
+    return 6;
+
   return MI.getDesc().getSize();
 }
 
diff --git a/llvm/lib/Target/SystemZ/SystemZLongBranch.cpp b/llvm/lib/Target/SystemZ/SystemZLongBranch.cpp
index b1964321c78a..9c985c16f082 100644
--- a/llvm/lib/Target/SystemZ/SystemZLongBranch.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZLongBranch.cpp
@@ -209,10 +209,24 @@ void SystemZLongBranch::skipTerminator(BlockPosition &Position,
     Position.Address += Terminator.ExtraRelaxSize;
 }
 
+static unsigned getInstSizeInBytes(const MachineInstr &MI,
+                                   const SystemZInstrInfo *TII) {
+  unsigned Size = TII->getInstSizeInBytes(MI);
+  assert((Size ||
+          // These do not have a size:
+          MI.isDebugOrPseudoInstr() || MI.isPosition() || MI.isKill() ||
+          MI.isImplicitDef() || MI.getOpcode() == SystemZ::MemBarrier ||
+          // These have a size that may be zero:
+          MI.isInlineAsm() || MI.getOpcode() == SystemZ::STACKMAP ||
+          MI.getOpcode() == SystemZ::PATCHPOINT) &&
+         "Missing size value for instruction.");
+  return Size;
+}
+
 // Return a description of terminator instruction MI.
 TerminatorInfo SystemZLongBranch::describeTerminator(MachineInstr &MI) {
   TerminatorInfo Terminator;
-  Terminator.Size = TII->getInstSizeInBytes(MI);
+  Terminator.Size = getInstSizeInBytes(MI, TII);
   if (MI.isConditionalBranch() || MI.isUnconditionalBranch()) {
     switch (MI.getOpcode()) {
     case SystemZ::J:
@@ -287,7 +301,7 @@ uint64_t SystemZLongBranch::initMBBInfo() {
     MachineBasicBlock::iterator MI = MBB->begin();
     MachineBasicBlock::iterator End = MBB->end();
     while (MI != End && !MI->isTerminator()) {
-      Block.Size += TII->getInstSizeInBytes(*MI);
+      Block.Size += getInstSizeInBytes(*MI, TII);
       ++MI;
     }
     skipNonTerminators(Position, Block);
diff --git a/llvm/test/CodeGen/SystemZ/patchpoint.ll b/llvm/test/CodeGen/SystemZ/patchpoint.ll
index bd67bdf12814..ef98190a2af0 100644
--- a/llvm/test/CodeGen/SystemZ/patchpoint.ll
+++ b/llvm/test/CodeGen/SystemZ/patchpoint.ll
@@ -97,6 +97,59 @@ entry:
   ret i64 %result
 }
 
+; Test that the number of bytes is reflected in the instruction size and
+; therefore cause relaxation of the initial branch.
+define void @patchpoint_size(i32 %Arg) {
+; CHECK-LABEL: patchpoint_size:
+; CHECK: # %bb.0:
+; CHECK-NEXT: stmg    %r14, %r15, 112(%r15)
+; CHECK-NEXT: .cfi_offset %r14, -48
+; CHECK-NEXT: .cfi_offset %r15, -40
+; CHECK-NEXT: aghi    %r15, -160
+; CHECK-NEXT: .cfi_def_cfa_offset 320
+; CHECK-NEXT: chi     %r2, 0
+; CHECK-NEXT: jge     .LBB6_2
+  %c = icmp eq i32 %Arg, 0
+  br i1 %c, label %block0, label %patch1
+
+block0:
+  call i64 @foo(i64 0, i64 0)
+  br label %exit
+
+patch1:
+  call void (i64, i32, i8*, i32, ...) @llvm.experimental.patchpoint.void(i64 0, i32 65536, i8* null, i32 0)
+  br label %exit
+
+exit:
+  ret void
+}
+
+define void @stackmap_size(i32 %Arg) {
+; CHECK-LABEL: stackmap_size:
+; CHECK: # %bb.0:
+; CHECK-NEXT: stmg    %r14, %r15, 112(%r15)
+; CHECK-NEXT: .cfi_offset %r14, -48
+; CHECK-NEXT: .cfi_offset %r15, -40
+; CHECK-NEXT: aghi    %r15, -160
+; CHECK-NEXT: .cfi_def_cfa_offset 320
+; CHECK-NEXT: chi     %r2, 0
+; CHECK-NEXT: jge     .LBB7_2
+  %c = icmp eq i32 %Arg, 0
+  br i1 %c, label %block0, label %stackmap1
+
+block0:
+  call i64 @foo(i64 0, i64 0)
+  br label %exit
+
+stackmap1:
+  call void (i64, i32, ...) @llvm.experimental.stackmap(i64 1, i32 65536)
+  br label %exit
+
+exit:
+  ret void
+}
+
+
 declare void @llvm.experimental.stackmap(i64, i32, ...)
 declare void @llvm.experimental.patchpoint.void(i64, i32, i8*, i32, ...)
 declare i64 @llvm.experimental.patchpoint.i64(i64, i32, i8*, i32, ...)