[PATCH] postscan_insn hook not called after input_asm

[PATCH] postscan_insn hook not called after input_asm

[Paul Iannetta]

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Hi,

While working on the Kalray port of gcc, I noticed that the hook TARGET_ASM_FINAL_POSTSCAN_INSN is not called after emitting an instruction coming from a basic asm block.  Here is a patch which fixes this behavior.

The following check:
```
$ find gcc/config/ -type f -exec grep "#define TARGET_ASM_FINAL" "{}" +
gcc/config/m68k/m68k.cc:#define TARGET_ASM_FINAL_POSTSCAN_INSN m68k_asm_final_postscan_insn
gcc/config/avr/avr.cc:#define TARGET_ASM_FINAL_POSTSCAN_INSN avr_asm_final_postscan_insn
gcc/config/mips/mips.cc:#define TARGET_ASM_FINAL_POSTSCAN_INSN mips_final_postscan_insn
```
reveals that m68k, avr and mips are the only affected targets upstream.

Paul Iannetta 
Kalray



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Re: [PING^1][PATCH] postscan_insn hook not called after input_asm

[Paul Iannetta]

Hi,

I would like to draw your attention on this patch, it's a pretty tiny patch which does not affect many targets.

----- Original Message -----
From: "gcc-patches" <gcc-patches@gcc.gnu.org>
To: "gcc-patches" <gcc-patches@gcc.gnu.org>
Sent: Tuesday, March 29, 2022 4:10:16 PM
Subject: [PATCH] postscan_insn hook not called after input_asm

Hi,

While working on the Kalray port of gcc, I noticed that the hook TARGET_ASM_FINAL_POSTSCAN_INSN is not called after emitting an instruction coming from a basic asm block.  Here is a patch which fixes this behavior.

The following check:
```
$ find gcc/config/ -type f -exec grep "#define TARGET_ASM_FINAL" "{}" +
gcc/config/m68k/m68k.cc:#define TARGET_ASM_FINAL_POSTSCAN_INSN m68k_asm_final_postscan_insn
gcc/config/avr/avr.cc:#define TARGET_ASM_FINAL_POSTSCAN_INSN avr_asm_final_postscan_insn
gcc/config/mips/mips.cc:#define TARGET_ASM_FINAL_POSTSCAN_INSN mips_final_postscan_insn
```
reveals that m68k, avr and mips are the only affected targets upstream.

Paul Iannetta 
Kalray

Re: [PATCH] postscan_insn hook not called after input_asm

[Jeff Law]

On 3/29/2022 8:10 AM, Paul Iannetta via Gcc-patches wrote:
> Hi,
>
> While working on the Kalray port of gcc, I noticed that the hook TARGET_ASM_FINAL_POSTSCAN_INSN is not called after emitting an instruction coming from a basic asm block.  Here is a patch which fixes this behavior.
>
> The following check:
> ```
> $ find gcc/config/ -type f -exec grep "#define TARGET_ASM_FINAL" "{}" +
> gcc/config/m68k/m68k.cc:#define TARGET_ASM_FINAL_POSTSCAN_INSN m68k_asm_final_postscan_insn
> gcc/config/avr/avr.cc:#define TARGET_ASM_FINAL_POSTSCAN_INSN avr_asm_final_postscan_insn
> gcc/config/mips/mips.cc:#define TARGET_ASM_FINAL_POSTSCAN_INSN mips_final_postscan_insn
> ```
> reveals that m68k, avr and mips are the only affected targets upstream.
So I know it's been a while since you posted this patch.   Do you recall 
the motivation behind it?  ie, was there something your port is doing 
that required the post-scan hook to be called on an ASM?

I'm not objecting to the patch, I just want to understand better what 
drove you to write it in the first place.

IIRC you can't ask for attributes on an ASM, meaning that the m68k hook 
will probably abort with this change.   You may need to adjust the m68k 
implementation so that it  doesn't fault if presented with an ASM.   
Something like this at the start should do the trick.

if (recog_memoized (insn) < 0)
   {
     flags_operand1 = flags_operand2 = NULL_RTX;
     return;
   }