diff --git a/llvm/test/CodeGen/X86/partial-fold32.ll b/llvm/test/CodeGen/X86/partial-fold32.ll
new file mode 100644
index 000000000000..ba3f73ba90fc
--- /dev/null
+++ b/llvm/test/CodeGen/X86/partial-fold32.ll
@@ -0,0 +1,26 @@
+; RUN: llc -mtriple=i686-unknown-linux-gnu -enable-misched=false < %s | FileCheck %s
+
+define fastcc i8 @fold32to8(i32 %add, i8 %spill) {
+; CHECK-LABEL: fold32to8:
+; CHECK:    movl %ecx, (%esp) # 4-byte Spill
+; CHECK:    movl (%esp), %eax # 4-byte Reload
+; CHECK:    subb %al, %dl
+entry:
+  tail call void asm sideeffect "", "~{eax},~{ebx},~{ecx},~{edi},~{esi},~{ebp},~{dirflag},~{fpsr},~{flags}"()
+  %trunc = trunc i32 %add to i8
+  %sub = sub i8 %spill, %trunc
+  ret i8 %sub
+}
+
+; Do not fold a 1-byte store into a 4-byte spill slot
+define fastcc i8 @nofold(i32 %add, i8 %spill) {
+; CHECK-LABEL: nofold:
+; CHECK:    movl %edx, (%esp) # 4-byte Spill
+; CHECK:    movl (%esp), %eax # 4-byte Reload
+; CHECK:    subb %cl, %al
+entry:
+  tail call void asm sideeffect "", "~{eax},~{ebx},~{edx},~{edi},~{esi},~{ebp},~{dirflag},~{fpsr},~{flags}"()
+  %trunc = trunc i32 %add to i8
+  %sub = sub i8 %spill, %trunc
+  ret i8 %sub
+}
diff --git a/llvm/test/CodeGen/X86/partial-fold64.ll b/llvm/test/CodeGen/X86/partial-fold64.ll
new file mode 100644
index 000000000000..b9ea7d6773a3
--- /dev/null
+++ b/llvm/test/CodeGen/X86/partial-fold64.ll
@@ -0,0 +1,43 @@
+; RUN: llc -mtriple=x86_64-unknown-linux-gnu -enable-misched=false < %s | FileCheck %s
+
+define i32 @fold64to32(i64 %add, i32 %spill) {
+; CHECK-LABEL: fold64to32:
+; CHECK:    movq %rdi, -{{[0-9]+}}(%rsp) # 8-byte Spill
+; CHECK:    movq -{{[0-9]+}}(%rsp), %rax # 8-byte Reload
+; CHECK:    subl %eax, %esi
+entry:
+  tail call void asm sideeffect "", "~{rax},~{rbx},~{rcx},~{rdx},~{rdi},~{rbp},~{r8},~{r9},~{r10},~{r11},~{r12},~{r13},~{r14},~{r15},~{dirflag},~{fpsr},~{flags}"()
+  %trunc = trunc i64 %add to i32
+  %sub = sub i32 %spill, %trunc
+  ret i32 %sub
+}
+
+define i8 @fold64to8(i64 %add, i8 %spill) {
+; CHECK-LABEL: fold64to8:
+; CHECK:    movq %rdi, -{{[0-9]+}}(%rsp) # 8-byte Spill
+; CHECK:    movq -{{[0-9]+}}(%rsp), %rax # 8-byte Reload
+; CHECK:    subb %al, %sil
+entry:
+  tail call void asm sideeffect "", "~{rax},~{rbx},~{rcx},~{rdx},~{rdi},~{rbp},~{r8},~{r9},~{r10},~{r11},~{r12},~{r13},~{r14},~{r15},~{dirflag},~{fpsr},~{flags}"()
+  %trunc = trunc i64 %add to i8
+  %sub = sub i8 %spill, %trunc
+  ret i8 %sub
+}
+
+; Do not fold a 4-byte store into a 8-byte spill slot
+; CHECK-LABEL: nofold
+; CHECK:    movq %rsi, -{{[0-9]+}}(%rsp) # 8-byte Spill
+; CHECK:    movq -{{[0-9]+}}(%rsp), %rax # 8-byte Reload
+; CHECK:    subl %edi, %eax
+; CHECK:    movq %rax, -{{[0-9]+}}(%rsp) # 8-byte Spill
+; CHECK:    movq -{{[0-9]+}}(%rsp), %rax # 8-byte Reload
+define i32 @nofold(i64 %add, i64 %spill) {
+entry:
+  tail call void asm sideeffect "", "~{rax},~{rbx},~{rcx},~{rdx},~{rsi},~{rbp},~{r8},~{r9},~{r10},~{r11},~{r12},~{r13},~{r14},~{r15},~{dirflag},~{fpsr},~{flags}"()
+  %trunc = trunc i64 %add to i32
+  %truncspill = trunc i64 %spill to i32
+  %sub = sub i32 %truncspill, %trunc
+  tail call void asm sideeffect "", "~{rax},~{rbx},~{rcx},~{rdx},~{rsi},~{rdi},~{rbp},~{r8},~{r9},~{r10},~{r11},~{r12},~{r13},~{r14},~{r15},~{dirflag},~{fpsr},~{flags}"()
+  ret i32 %sub
+}
+