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Re: [Qemu-devel] [PATCH] tcg: try sti when moving a constant into a dead
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From: |
Richard Henderson |
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Subject: |
Re: [Qemu-devel] [PATCH] tcg: try sti when moving a constant into a dead memory temp |
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Date: |
Tue, 20 Sep 2016 13:41:08 -0700 |
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User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 |
On 09/15/2016 06:16 AM, Paolo Bonzini wrote:
> This comes from free from unifying tcg_reg_alloc_mov and
> tcg_reg_alloc_movi's handling of TEMP_VAL_CONST. It triggers
> often on moves to cc_dst, such as the following translation
> of "sub $0x3c,%esp":
>
> before: after:
> subl $0x3c,%ebp subl $0x3c,%ebp
> movl %ebp,0x10(%r14) movl %ebp,0x10(%r14)
> movl $0x3c,%ebx movl $0x3c,0x2c(%r14)
> movl %ebx,0x2c(%r14)
What's the input here? From just this snippet it looks as if we should have
converted both of them to an immediate store.
r~