Index: lib/MC/MCAssembler.cpp
===================================================================
--- lib/MC/MCAssembler.cpp
+++ lib/MC/MCAssembler.cpp
@@ -256,7 +256,7 @@
     else { // EndOfFragment > BundleSize
       return 2 * BundleSize - EndOfFragment;
     }
-  } else if (EndOfFragment > BundleSize)
+  } else if (OffsetInBundle > 0 && EndOfFragment > BundleSize)
     return BundleSize - OffsetInBundle;
   else
     return 0;
@@ -586,15 +586,15 @@
   //
   // When the -mc-relax-all flag is used, we optimize bundling by writting the
   // bundle padding directly into fragments when the instructions are emitted
-  // inside the streamer.
+  // inside the streamer. However, we still need to ensure that fragments are
+  // bundle aligned.
   //
-  if (Assembler.isBundlingEnabled() && !Assembler.getRelaxAll() &&
-      F->hasInstructions()) {
+  if (Assembler.isBundlingEnabled() && F->hasInstructions()) {
     assert(isa<MCEncodedFragment>(F) &&
            "Only MCEncodedFragment implementations have instructions");
     uint64_t FSize = Assembler.computeFragmentSize(*this, *F);
 
-    if (FSize > Assembler.getBundleAlignSize())
+    if (!Assembler.getRelaxAll() && FSize > Assembler.getBundleAlignSize())
       report_fatal_error("Fragment can't be larger than a bundle size");
 
     uint64_t RequiredBundlePadding = computeBundlePadding(Assembler, F,
Index: test/MC/X86/AlignedBundling/misaligned-bundle-group.s
===================================================================
--- /dev/null
+++ test/MC/X86/AlignedBundling/misaligned-bundle-group.s
@@ -0,0 +1,19 @@
+# RUN: llvm-mc -filetype=obj -triple i686-pc-linux-gnu %s -o - \
+# RUN:   | llvm-objdump -disassemble -no-show-raw-insn - | FileCheck -check-prefix=CHECK -check-prefix=CHECK-OPT %s
+# RUN: llvm-mc -filetype=obj -triple i686-pc-linux-gnu -mc-relax-all %s -o - \
+# RUN:   | llvm-objdump -disassemble -no-show-raw-insn - | FileCheck -check-prefix=CHECK -check-prefix=CHECK-RELAX %s
+
+        .bundle_align_mode 5
+        .text
+        hlt
+        .align  16
+        .bundle_lock align_to_end
+# CHECK:            1:  nopw %cs:(%eax,%eax)
+# CHECK-OPT:        10: nopw (%eax,%eax)
+# CHECK-RELAX       10: nopw %cs:(%eax,%eax)
+# CHECK-RELAX:      1f: nop
+# CHECK-RELAX:      20: nopw %cs:(%eax,%eax)
+# CHECK-RELAX:      2f: nopw %cs:(%eax,%eax)
+        movl $0x1, (%esp)
+        .bundle_unlock
+        movl $0x2, (%esp)
Index: test/MC/X86/AlignedBundling/misaligned-bundle.s
===================================================================
--- /dev/null
+++ test/MC/X86/AlignedBundling/misaligned-bundle.s
@@ -0,0 +1,23 @@
+# RUN: llvm-mc -filetype=obj -triple i686-pc-linux-gnu %s -o - \
+# RUN:   | llvm-objdump -disassemble -no-show-raw-insn - | FileCheck -check-prefix=CHECK -check-prefix=CHECK-OPT %s
+# RUN: llvm-mc -filetype=obj -triple i686-pc-linux-gnu -mc-relax-all %s -o - \
+# RUN:   | llvm-objdump -disassemble -no-show-raw-insn - | FileCheck -check-prefix=CHECK -check-prefix=CHECK-RELAX %s
+
+        .bundle_align_mode 5
+        .text
+        hlt
+        .align  16
+# CHECK:            1:  nopw %cs:(%eax,%eax)
+# CHECK-RELAX:      10: nopw %cs:(%eax,%eax)
+# CHECK-RELAX:      1f: nop
+        movl $0x1, (%esp)
+        movl $0x1, (%esp)
+# CHECK-OPT:        1e: nop
+        movl $0x2, 0x1(%esp)
+        movl $0x2, 0x1(%esp)
+# CHECK-RELAX:      3e: nop
+        movl $0x2, 0x1(%esp)
+        movl $0x2, (%esp)
+# CHECK-OPT:        3f: nop
+        movl $0x3, (%esp)
+        movl $0x3, (%esp)