V850 decompilation: GP is callee-saved and does not function correctly. As shown in the figure below, after the sub_28790 function, GP becomes undefined. [image]

Hello, Generally, on V850 gp is used as a global register. If this is not the case, enable the corresponding setting in the processor-specific options. [image] If it’s still not working as expected, please create a ticket on support.hex-ray.com and add a sample.

Thank you for the update. Could you please submit an issue with sample as requested?

Thank you. It seems the callee-saved option is a red herring, and gp is a standard global register in this binary, but its value is not used by the decompiler for some reason. We’ll investigate this.

This pattern has been fixed in 9.3 SP1 .

The issue has not been resolved and remains undefined. Taking the sub_287DC function as an example, the decompilation results are shown in the figure below. [image]

You need to disable “GP is callee-saved” option, because it’s wrong for this firmware. int __fastcall sub_287DC(unsigned __int8 a1, unsigned __int8 a2, char a3) { int v4; // r29 int result; // r10 v4 = a1; result = sub_28790(a1, a2); if ( result == 1 ) { MEMORY[0xFEE03B80] = 127; …

Once I set the value for the GP register, it can’t be disabled. Even after I disable it and click OK, it remains the same, and when I open the settings again, the “GP is callee-saved” option is automatically checked again.

This is a recording of my actions; after clicking “OK,” I pressed F5 to refresh. PixPin_2026-03-30_16-07-56.zip (806.9 KB)

V850 Decompiler GP is callee-saved issues

IDA General Bugs

sskki February 24, 2026, 2:38pm 5

xx.bin.i64.zip (2.1 MB)

sample function sub_287DC

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V850 Decompiler GP is callee-saved issues

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