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6c4265a541
one-byte NOPs. If the processor actually executes those NOPs, as it sometimes does with aligned bundling, this can have a performance impact. From my micro-benchmarks run on my one machine, a 15-byte NOP followed by twelve one-byte NOPs is about 20% worse than a 15 followed by a 12. This patch changes NOP emission to emit as many 15-byte (the maximum) as possible followed by at most one shorter NOP. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176464 91177308-0d34-0410-b5e6-96231b3b80d8
28 lines
773 B
ArmAsm
28 lines
773 B
ArmAsm
# RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu %s -o - \
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# RUN: | llvm-objdump -disassemble -no-show-raw-insn - | FileCheck %s
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# Test that long nops are generated for padding where possible.
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.text
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foo:
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.bundle_align_mode 5
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# This callq instruction is 5 bytes long
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.bundle_lock align_to_end
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callq bar
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.bundle_unlock
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# To align this group to a bundle end, we need a 15-byte NOP and a 12-byte NOP.
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# CHECK: 0: nop
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# CHECK-NEXT: f: nop
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# CHECK-NEXT: 1b: callq
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# This push instruction is 1 byte long
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.bundle_lock align_to_end
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push %rax
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.bundle_unlock
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# To align this group to a bundle end, we need two 15-byte NOPs, and a 1-byte.
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# CHECK: 20: nop
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# CHECK-NEXT: 2f: nop
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# CHECK-NEXT: 3e: nop
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# CHECK-NEXT: 3f: pushq
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