https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115817
Georg-Johann Lay changed:
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Ever confirmed|0 |1
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115817
--- Comment #9 from Georg-Johann Lay ---
What can be used as a kind of work-around (and may be even better than the code
with improved Binutils as proposed above), is to hide the value of 0 from the
compiler:
volatile uint8_t var;
__attribute(
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115817
--- Comment #8 from Georg-Johann Lay ---
See https://sourceware.org/bugzilla/show_bug.cgi?id=32704
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115817
Georg-Johann Lay changed:
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CC||ul...@t-online.de
--- Comment #7 fro
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115817
--- Comment #6 from Dmytro Bagrii ---
(In reply to Georg-Johann Lay from comment #5)
Thank you for explanation.
> LDI cannot be used since it only allows R16...R31.
I meant do not treat 0 as a special value and use LDI R24,0x00 The same as fo
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115817
--- Comment #5 from Georg-Johann Lay ---
(In reply to Dmytro Bagrii from comment #4)
> gcc is smart enough not to initialize R1 when it is not used.
Actually not. The decision whether __zero_reg__ is required in an ISR is
worked out by the asse
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115817
--- Comment #4 from Dmytro Bagrii ---
Of course, there are various cores, i'm just speculating regarding necessity of
preserving R1.
For now the issue is worked around with inline assembler. It was surprise for
me to see the .text size increase
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115817
--- Comment #3 from Georg-Johann Lay ---
Setting R1 to 0 in an ISR prologue is not redundant, because R1 may be non-zero
due to a variety of reasons, for example when the interrupted code uses MUL
just to mention one.
Moreover, on Reduced Tiny
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115817
--- Comment #2 from Dmytro Bagrii ---
Yes, in "regular" function single STS for storing zero is better than LDI/STS
for storing non-zero, assuming r1 is already zeroed.
If it were guaranteed that ISR cannot be invoked before libc's .init2 secti
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115817
Georg-Johann Lay changed:
What|Removed |Added
Priority|P3 |P4
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