Index: lib/CodeGen/RegisterPressure.cpp
===================================================================
--- lib/CodeGen/RegisterPressure.cpp
+++ lib/CodeGen/RegisterPressure.cpp
@@ -681,8 +681,7 @@
       PressureDiff::iterator J;
       for (J = std::next(I); J != E && J->isValid(); ++J, ++I)
         *I = *J;
-      if (J != E)
-        *I = *J;
+      *I = PressureChange();
     }
   }
 }
Index: test/CodeGen/X86/divrem.ll
===================================================================
--- test/CodeGen/X86/divrem.ll
+++ test/CodeGen/X86/divrem.ll
@@ -57,11 +57,11 @@
 ; X32-LABEL: si32:
 ; X32:       # %bb.0:
 ; X32-NEXT:    pushl %esi
-; X32-NEXT:    movl {{[0-9]+}}(%esp), %ecx
-; X32-NEXT:    movl {{[0-9]+}}(%esp), %esi
 ; X32-NEXT:    movl {{[0-9]+}}(%esp), %eax
 ; X32-NEXT:    cltd
 ; X32-NEXT:    idivl {{[0-9]+}}(%esp)
+; X32-NEXT:    movl {{[0-9]+}}(%esp), %ecx
+; X32-NEXT:    movl {{[0-9]+}}(%esp), %esi
 ; X32-NEXT:    movl %eax, (%esi)
 ; X32-NEXT:    movl %edx, (%ecx)
 ; X32-NEXT:    popl %esi
@@ -87,11 +87,11 @@
 ; X32-LABEL: si16:
 ; X32:       # %bb.0:
 ; X32-NEXT:    pushl %esi
-; X32-NEXT:    movl {{[0-9]+}}(%esp), %ecx
-; X32-NEXT:    movl {{[0-9]+}}(%esp), %esi
 ; X32-NEXT:    movzwl {{[0-9]+}}(%esp), %eax
 ; X32-NEXT:    cwtd
 ; X32-NEXT:    idivw {{[0-9]+}}(%esp)
+; X32-NEXT:    movl {{[0-9]+}}(%esp), %ecx
+; X32-NEXT:    movl {{[0-9]+}}(%esp), %esi
 ; X32-NEXT:    movw %ax, (%esi)
 ; X32-NEXT:    movw %dx, (%ecx)
 ; X32-NEXT:    popl %esi
@@ -118,11 +118,11 @@
 ; X32-LABEL: si8:
 ; X32:       # %bb.0:
 ; X32-NEXT:    pushl %ebx
-; X32-NEXT:    movl {{[0-9]+}}(%esp), %ecx
-; X32-NEXT:    movl {{[0-9]+}}(%esp), %edx
 ; X32-NEXT:    movb {{[0-9]+}}(%esp), %al
 ; X32-NEXT:    cbtw
 ; X32-NEXT:    idivb {{[0-9]+}}(%esp)
+; X32-NEXT:    movl {{[0-9]+}}(%esp), %ecx
+; X32-NEXT:    movl {{[0-9]+}}(%esp), %edx
 ; X32-NEXT:    movsbl %ah, %ebx
 ; X32-NEXT:    movb %al, (%edx)
 ; X32-NEXT:    movb %bl, (%ecx)
@@ -201,11 +201,11 @@
 ; X32-LABEL: ui32:
 ; X32:       # %bb.0:
 ; X32-NEXT:    pushl %esi
-; X32-NEXT:    movl {{[0-9]+}}(%esp), %ecx
-; X32-NEXT:    movl {{[0-9]+}}(%esp), %esi
 ; X32-NEXT:    movl {{[0-9]+}}(%esp), %eax
 ; X32-NEXT:    xorl %edx, %edx
 ; X32-NEXT:    divl {{[0-9]+}}(%esp)
+; X32-NEXT:    movl {{[0-9]+}}(%esp), %ecx
+; X32-NEXT:    movl {{[0-9]+}}(%esp), %esi
 ; X32-NEXT:    movl %eax, (%esi)
 ; X32-NEXT:    movl %edx, (%ecx)
 ; X32-NEXT:    popl %esi
@@ -231,11 +231,11 @@
 ; X32-LABEL: ui16:
 ; X32:       # %bb.0:
 ; X32-NEXT:    pushl %esi
-; X32-NEXT:    movl {{[0-9]+}}(%esp), %ecx
-; X32-NEXT:    movl {{[0-9]+}}(%esp), %esi
 ; X32-NEXT:    movzwl {{[0-9]+}}(%esp), %eax
 ; X32-NEXT:    xorl %edx, %edx
 ; X32-NEXT:    divw {{[0-9]+}}(%esp)
+; X32-NEXT:    movl {{[0-9]+}}(%esp), %ecx
+; X32-NEXT:    movl {{[0-9]+}}(%esp), %esi
 ; X32-NEXT:    movw %ax, (%esi)
 ; X32-NEXT:    movw %dx, (%ecx)
 ; X32-NEXT:    popl %esi
@@ -262,11 +262,11 @@
 ; X32-LABEL: ui8:
 ; X32:       # %bb.0:
 ; X32-NEXT:    pushl %ebx
-; X32-NEXT:    movl {{[0-9]+}}(%esp), %ecx
-; X32-NEXT:    movl {{[0-9]+}}(%esp), %edx
 ; X32-NEXT:    movzbl {{[0-9]+}}(%esp), %eax
 ; X32-NEXT:    # kill: def $eax killed $eax def $ax
 ; X32-NEXT:    divb {{[0-9]+}}(%esp)
+; X32-NEXT:    movl {{[0-9]+}}(%esp), %ecx
+; X32-NEXT:    movl {{[0-9]+}}(%esp), %edx
 ; X32-NEXT:    movzbl %ah, %ebx
 ; X32-NEXT:    movb %al, (%edx)
 ; X32-NEXT:    movb %bl, (%ecx)
Index: test/CodeGen/X86/divrem8_ext.ll
===================================================================
--- test/CodeGen/X86/divrem8_ext.ll
+++ test/CodeGen/X86/divrem8_ext.ll
@@ -152,8 +152,8 @@
 ; X32-LABEL: test_srem_noext_ah:
 ; X32:       # %bb.0:
 ; X32-NEXT:    movb {{[0-9]+}}(%esp), %al
-; X32-NEXT:    movb {{[0-9]+}}(%esp), %cl
 ; X32-NEXT:    cbtw
+; X32-NEXT:    movb {{[0-9]+}}(%esp), %cl
 ; X32-NEXT:    idivb %cl
 ; X32-NEXT:    movsbl %ah, %eax
 ; X32-NEXT:    addb %cl, %al
Index: test/CodeGen/X86/musttail-varargs.ll
===================================================================
--- test/CodeGen/X86/musttail-varargs.ll
+++ test/CodeGen/X86/musttail-varargs.ll
@@ -83,6 +83,7 @@
 ; LINUX-NEXT:    movq %rbp, %rdx
 ; LINUX-NEXT:    movq %r13, %rcx
 ; LINUX-NEXT:    movq %r12, %r8
+; LINUX-NEXT:    movb {{[-0-9]+}}(%r{{[sb]}}p), %al # 1-byte Reload
 ; LINUX-NEXT:    movq %r15, %r9
 ; LINUX-NEXT:    movaps {{[-0-9]+}}(%r{{[sb]}}p), %xmm0 # 16-byte Reload
 ; LINUX-NEXT:    movaps {{[-0-9]+}}(%r{{[sb]}}p), %xmm1 # 16-byte Reload
@@ -92,7 +93,6 @@
 ; LINUX-NEXT:    movaps {{[-0-9]+}}(%r{{[sb]}}p), %xmm5 # 16-byte Reload
 ; LINUX-NEXT:    movaps {{[-0-9]+}}(%r{{[sb]}}p), %xmm6 # 16-byte Reload
 ; LINUX-NEXT:    movaps {{[-0-9]+}}(%r{{[sb]}}p), %xmm7 # 16-byte Reload
-; LINUX-NEXT:    movb {{[-0-9]+}}(%r{{[sb]}}p), %al # 1-byte Reload
 ; LINUX-NEXT:    addq $360, %rsp # imm = 0x168
 ; LINUX-NEXT:    .cfi_def_cfa_offset 56
 ; LINUX-NEXT:    popq %rbx
@@ -177,6 +177,7 @@
 ; LINUX-X32-NEXT:    movq %rbp, %rdx
 ; LINUX-X32-NEXT:    movq %r13, %rcx
 ; LINUX-X32-NEXT:    movq %r12, %r8
+; LINUX-X32-NEXT:    movb {{[-0-9]+}}(%e{{[sb]}}p), %al # 1-byte Reload
 ; LINUX-X32-NEXT:    movq %r15, %r9
 ; LINUX-X32-NEXT:    movaps {{[-0-9]+}}(%e{{[sb]}}p), %xmm0 # 16-byte Reload
 ; LINUX-X32-NEXT:    movaps {{[-0-9]+}}(%e{{[sb]}}p), %xmm1 # 16-byte Reload
@@ -186,7 +187,6 @@
 ; LINUX-X32-NEXT:    movaps {{[-0-9]+}}(%e{{[sb]}}p), %xmm5 # 16-byte Reload
 ; LINUX-X32-NEXT:    movaps {{[-0-9]+}}(%e{{[sb]}}p), %xmm6 # 16-byte Reload
 ; LINUX-X32-NEXT:    movaps {{[-0-9]+}}(%e{{[sb]}}p), %xmm7 # 16-byte Reload
-; LINUX-X32-NEXT:    movb {{[-0-9]+}}(%e{{[sb]}}p), %al # 1-byte Reload
 ; LINUX-X32-NEXT:    addl $344, %esp # imm = 0x158
 ; LINUX-X32-NEXT:    .cfi_def_cfa_offset 56
 ; LINUX-X32-NEXT:    popq %rbx
Index: test/CodeGen/X86/pr38539.ll
===================================================================
--- test/CodeGen/X86/pr38539.ll
+++ test/CodeGen/X86/pr38539.ll
@@ -18,15 +18,15 @@
 ; X64-NEXT:    .cfi_offset %r14, -24
 ; X64-NEXT:    .cfi_offset %rbp, -16
 ; X64-NEXT:    movzbl {{[0-9]+}}(%rsp), %ebp
-; X64-NEXT:    movq %rbp, %rcx
-; X64-NEXT:    shlq $62, %rcx
-; X64-NEXT:    sarq $62, %rcx
 ; X64-NEXT:    movq (%rsp), %rbx
 ; X64-NEXT:    movb (%rax), %al
 ; X64-NEXT:    movzbl %al, %eax
 ; X64-NEXT:    # kill: def $eax killed $eax def $ax
 ; X64-NEXT:    divb (%rax)
 ; X64-NEXT:    movl %eax, %r14d
+; X64-NEXT:    movq %rbp, %rcx
+; X64-NEXT:    shlq $62, %rcx
+; X64-NEXT:    sarq $62, %rcx
 ; X64-NEXT:    xorl %edi, %edi
 ; X64-NEXT:    xorl %esi, %esi
 ; X64-NEXT:    movq %rbx, %rdx
@@ -86,11 +86,6 @@
 ; X86-NEXT:    .cfi_offset %edi, -16
 ; X86-NEXT:    .cfi_offset %ebx, -12
 ; X86-NEXT:    movzbl {{[0-9]+}}(%esp), %esi
-; X86-NEXT:    movl %esi, %ecx
-; X86-NEXT:    shll $30, %ecx
-; X86-NEXT:    movl %ecx, %edx
-; X86-NEXT:    sarl $30, %edx
-; X86-NEXT:    sarl $31, %ecx
 ; X86-NEXT:    movl {{[0-9]+}}(%esp), %edi
 ; X86-NEXT:    movl {{[0-9]+}}(%esp), %ebx
 ; X86-NEXT:    movb (%eax), %al
@@ -98,16 +93,21 @@
 ; X86-NEXT:    # kill: def $eax killed $eax def $ax
 ; X86-NEXT:    divb (%eax)
 ; X86-NEXT:    movb %al, {{[-0-9]+}}(%e{{[sb]}}p) # 1-byte Spill
-; X86-NEXT:    leal {{[0-9]+}}(%esp), %eax
+; X86-NEXT:    movl %esi, %eax
+; X86-NEXT:    shll $30, %eax
+; X86-NEXT:    movl %eax, %ecx
+; X86-NEXT:    sarl $30, %ecx
+; X86-NEXT:    sarl $31, %eax
+; X86-NEXT:    leal {{[0-9]+}}(%esp), %edx
+; X86-NEXT:    pushl %eax
 ; X86-NEXT:    pushl %ecx
-; X86-NEXT:    pushl %edx
 ; X86-NEXT:    pushl %ebx
 ; X86-NEXT:    pushl %edi
 ; X86-NEXT:    pushl $0
 ; X86-NEXT:    pushl $0
 ; X86-NEXT:    pushl $0
 ; X86-NEXT:    pushl $0
-; X86-NEXT:    pushl %eax
+; X86-NEXT:    pushl %edx
 ; X86-NEXT:    calll __modti3
 ; X86-NEXT:    addl $32, %esp
 ; X86-NEXT:    movl {{[0-9]+}}(%esp), %eax
@@ -239,16 +239,16 @@
 ; X86-NEXT:    .cfi_offset %edi, -16
 ; X86-NEXT:    .cfi_offset %ebx, -12
 ; X86-NEXT:    movzbl {{[0-9]+}}(%esp), %esi
-; X86-NEXT:    movl %esi, %ecx
-; X86-NEXT:    shll $30, %ecx
-; X86-NEXT:    sarl $30, %ecx
 ; X86-NEXT:    movl (%esp), %edi
 ; X86-NEXT:    movb (%eax), %al
 ; X86-NEXT:    movzbl %al, %eax
 ; X86-NEXT:    # kill: def $eax killed $eax def $ax
 ; X86-NEXT:    divb (%eax)
 ; X86-NEXT:    movl %eax, %ebx
-; X86-NEXT:    pushl %ecx
+; X86-NEXT:    movl %esi, %eax
+; X86-NEXT:    shll $30, %eax
+; X86-NEXT:    sarl $30, %eax
+; X86-NEXT:    pushl %eax
 ; X86-NEXT:    pushl %edi
 ; X86-NEXT:    pushl $0
 ; X86-NEXT:    pushl $0