forked from OSchip/llvm-project
75 lines
2.3 KiB
ArmAsm
75 lines
2.3 KiB
ArmAsm
# RUN: llvm-mc -mcpu=skylake -filetype=obj -triple x86_64-pc-linux-gnu %s | llvm-objdump -d --section=.text - | FileCheck %s
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.file "test.c"
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.text
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.section .text
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# Demonstrate that we can relax instructions to provide padding, not
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# just insert nops. jmps are being used for ease of demonstration.
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# CHECK: .text
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# CHECK: 0: eb 1f jmp 31 <foo>
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# CHECK: 2: e9 1a 00 00 00 jmp 26 <foo>
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# CHECK: 7: e9 15 00 00 00 jmp 21 <foo>
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# CHECK: c: e9 10 00 00 00 jmp 16 <foo>
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# CHECK: 11: e9 0b 00 00 00 jmp 11 <foo>
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# CHECK: 16: e9 06 00 00 00 jmp 6 <foo>
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# CHECK: 1b: e9 01 00 00 00 jmp 1 <foo>
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# CHECK: 20: cc int3
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.p2align 4
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jmp foo
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jmp foo
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jmp foo
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jmp foo
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jmp foo
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jmp foo
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jmp foo
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.p2align 5
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int3
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foo:
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ret
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# Check that we're not shifting aroudn the offsets of labels - doing
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# that would require a further round of relaxation
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# CHECK: <bar>:
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# CHECK: 22: eb fe jmp -2 <bar>
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# CHECK: 24: 66 2e 0f 1f 84 00 00 00 00 00 nopw %cs:(%rax,%rax)
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# CHECK: 2e: 66 90 nop
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# CHECK: 30: 0f 0b ud2
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bar:
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jmp bar
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nobypass:
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.p2align 4
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ud2
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# Canonical toy loop to show benefit - we can align the loop header with
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# fewer nops by relaxing the branch, even though we don't need to
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# CHECK: <loop_preheader>:
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# CHECK: 45: 48 85 c0 testq %rax, %rax
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# CHECK: 48: 0f 8e 22 00 00 00 jle 34 <loop_exit>
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# CHECK: 4e: 66 2e 0f 1f 84 00 00 00 00 00 nopw %cs:(%rax,%rax)
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# CHECK: 58: 0f 1f 84 00 00 00 00 00 nopl (%rax,%rax)
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# CHECK: <loop_header>:
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# CHECK: 60: 48 83 e8 01 subq $1, %rax
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# CHECK: 64: 48 85 c0 testq %rax, %rax
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# CHECK: 67: 7e 07 jle 7 <loop_exit>
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# CHECK: 69: e9 f2 ff ff ff jmp -14 <loop_header>
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# CHECK: 6e: 66 90 nop
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# CHECK: <loop_exit>:
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# CHECK: 70: c3 retq
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.p2align 5
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.skip 5
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loop_preheader:
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testq %rax, %rax
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jle loop_exit
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.p2align 5
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loop_header:
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subq $1, %rax
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testq %rax, %rax
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jle loop_exit
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jmp loop_header
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.p2align 4
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loop_exit:
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ret
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