diff options
Diffstat (limited to 'llvm/test/CodeGen/X86/base-pointer-and-cmpxchg.ll')
| -rw-r--r-- | llvm/test/CodeGen/X86/base-pointer-and-cmpxchg.ll | 51 |
1 files changed, 51 insertions, 0 deletions
diff --git a/llvm/test/CodeGen/X86/base-pointer-and-cmpxchg.ll b/llvm/test/CodeGen/X86/base-pointer-and-cmpxchg.ll new file mode 100644 index 00000000000..8de6d64428e --- /dev/null +++ b/llvm/test/CodeGen/X86/base-pointer-and-cmpxchg.ll @@ -0,0 +1,51 @@ +; RUN: llc -mtriple=x86_64-apple-macosx -mattr=+cx16 -x86-use-base-pointer=true -stackrealign -stack-alignment=32 %s -o - | FileCheck --check-prefix=CHECK --check-prefix=USE_BASE --check-prefix=USE_BASE_64 %s +; RUN: llc -mtriple=x86_64-apple-macosx -mattr=+cx16 -x86-use-base-pointer=false -stackrealign -stack-alignment=32 %s -o - | FileCheck --check-prefix=CHECK --check-prefix=DONT_USE_BASE %s +; RUN: llc -mtriple=x86_64-linux-gnux32 -mattr=+cx16 -x86-use-base-pointer=true -stackrealign -stack-alignment=32 %s -o - | FileCheck --check-prefix=CHECK --check-prefix=USE_BASE --check-prefix=USE_BASE_32 %s +; RUN: llc -mtriple=x86_64-linux-gnux32 -mattr=+cx16 -x86-use-base-pointer=false -stackrealign -stack-alignment=32 %s -o - | FileCheck --check-prefix=CHECK --check-prefix=DONT_USE_BASE %s + +; This function uses dynamic allocated stack to force the use +; of a frame pointer. +; The inline asm clobbers a bunch of registers to make sure +; the frame pointer will need to be used (for spilling in that case). +; +; Then, we check that when we use rbx as the base pointer, +; we do not use cmpxchg, since using that instruction requires +; to clobbers rbx to set the arguments of the instruction and when +; rbx is used as the base pointer, RA cannot fix the code for us. +; +; CHECK-LABEL: cmp_and_swap16: +; Check that we actually use rbx. +; gnux32 use the 32bit variant of the registers. +; USE_BASE_64: movq %rsp, %rbx +; USE_BASE_32: movl %esp, %ebx +; +; Make sure the base pointer is saved before the RBX argument for +; cmpxchg16b is set. +; +; Because of how the test is written, we spill SAVE_RBX. +; However, it would have been perfectly fine to just keep it in register. +; USE_BASE: movq %rbx, [[SAVE_RBX_SLOT:[0-9]*\(%[er]bx\)]] +; +; SAVE_RBX must be in register before we clobber rbx. +; It is fine to use any register but rbx and the ones defined and use +; by cmpxchg. Since such regex would be complicated to write, just stick +; to the numbered registers. The bottom line is: if this test case fails +; because of that regex, this is likely just the regex being too conservative. +; USE_BASE: movq [[SAVE_RBX_SLOT]], [[SAVE_RBX:%r[0-9]+]] +; +; USE_BASE: movq {{[^ ]+}}, %rbx +; USE_BASE-NEXT: cmpxchg16b +; USE_BASE-NEXT: movq [[SAVE_RBX]], %rbx +; +; DONT_USE_BASE-NOT: movq %rsp, %rbx +; DONT_USE_BASE-NOT: movl %esp, %ebx +; DONT_USE_BASE: cmpxchg +define i1 @cmp_and_swap16(i128 %a, i128 %b, i128* %addr, i32 %n) { + %dummy = alloca i32, i32 %n +tail call void asm sideeffect "nop", "~{rax},~{rcx},~{rdx},~{rsi},~{rdi},~{rbp},~{r8},~{r9},~{r10},~{r11},~{r12},~{r13},~{r14},~{r15}"() + %cmp = cmpxchg i128* %addr, i128 %a, i128 %b seq_cst seq_cst + %res = extractvalue { i128, i1 } %cmp, 1 + %idx = getelementptr i32, i32* %dummy, i32 5 + store i32 %n, i32* %idx + ret i1 %res +} |
