llvm-6502/test/MC/X86/x86_long_nop.s
Alexey Volkov 1bd30dce7b [X86] Limit maximum nop length on Silvermont
Silvermont can only decode one instruction per cycle if the instruction exceeds 8 bytes.
Also in Silvermont instructions with more than 3 prefixes will cause 3 cycle penalty.
Maximum nop length is limited to 7 bytes when used for padding on Silvermont.
For other x86 processors max nop length remains unchanged 15 bytes.

Differential Revision: http://reviews.llvm.org/D4374


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@212321 91177308-0d34-0410-b5e6-96231b3b80d8
2014-07-04 07:14:56 +00:00

26 lines
1.1 KiB
ArmAsm

# RUN: llvm-mc -filetype=obj -arch=x86 -triple=x86_64-pc-linux-gnu %s | llvm-objdump -d -no-show-raw-insn - | FileCheck %s
# RUN: llvm-mc -filetype=obj -arch=x86 -triple=i686-pc-linux-gnu %s | llvm-objdump -d -no-show-raw-insn - | FileCheck %s
# RUN: llvm-mc -filetype=obj -arch=x86 -triple=x86_64-apple-darwin10.0 %s | llvm-objdump -d -no-show-raw-insn - | FileCheck %s
# RUN: llvm-mc -filetype=obj -arch=x86 -triple=i686-apple-darwin8 %s | llvm-objdump -d -no-show-raw-insn - | FileCheck %s
# RUN: llvm-mc -filetype=obj -arch=x86 -triple=i686-pc-linux-gnu -mcpu=slm %s | llvm-objdump -d -no-show-raw-insn - | FileCheck --check-prefix=SLM %s
# Ensure alignment directives also emit sequences of 15-byte NOPs on processors
# capable of using long NOPs.
inc %eax
.p2align 5
inc %eax
# CHECK: 0: inc
# CHECK-NEXT: 1: nop
# CHECK-NEXT: 10: nop
# CHECK-NEXT: 1f: nop
# CHECK-NEXT: 20: inc
# On Silvermont we emit only 7 byte NOPs since longer NOPs are not profitable
# SLM: 0: inc
# SLM-NEXT: 1: nop
# SLM-NEXT: 8: nop
# SLM-NEXT: f: nop
# SLM-NEXT: 16: nop
# SLM-NEXT: 1d: nop
# SLM-NEXT: 20: inc