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From: "gjl at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/97276] A whole if-block is ignored by avr-gcc 9.3.0
Date: Thu, 23 Feb 2023 15:44:07 +0000 [thread overview]
Message-ID: <bug-97276-4-RQclkzX7ME@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-97276-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97276
--- Comment #4 from Georg-Johann Lay <gjl at gcc dot gnu.org> ---
Created attachment 54518
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54518&action=edit
pwn-i.c pre-compiled test case
Ok, I found it and attached a cleaned-up version.
IIUC correctly, the relevant options you are using to compile are: -O1
-mmcu=atxmega32a4 -g -ggdb -std=gnu99
With these options (and with -fverbose-asm to easier navigate in asm) I could
not reproduce the problem with avr-gcc v8.5. The respective part of .s reads
(I dropped -g for legibility, but with -g it's same):
; pwm-i.c:287: if (last_brightness < 181 && j >= 181)
ldi r30,lo8(-76) ; , ; 320 [c=4 l=1] movqi_insn/1
cp r30,r11 ; , last_brightness ; 193 [c=4 l=1]
cmpqi3/1
brsh .+2 ; ; 194 [c=16 l=2] branch
rjmp .L16 ;
; pwm-i.c:287: if (last_brightness < 181 && j >= 181)
cpi r22,lo8(-75) ; iftmp.3_5, ; 196 [c=4 l=1] cmpqi3/2
brsh .+2 ; ; 197 [c=16 l=2] branch
rjmp .L16 ;
; pwm-i.c:289: slot->top = 0xfe00;
st X+,r8 ; tmp226 ; 200 [c=4 l=3] *movhi/3
st X,r9 ; tmp226
sbiw r26,1
; pwm-i.c:290: slot->mask = ~mask;
movw r30,r24 ; tmp200, mask ; 321 [c=4 l=1] *movhi/0
com r30 ; tmp200 ; 201 [c=8 l=2] one_cmplhi2
com r31 ; tmp200
; pwm-i.c:290: slot->mask = ~mask;
adiw r26,2 ; slot_172->mask ; 202 [c=4 l=4] *movhi/3
st X+,r30 ; tmp200
st X,r31 ; tmp200
sbiw r26,2+1 ; slot_172->mask
; pwm-i.c:291: ++slot;
adiw r26,4 ; slot, ; 203 [c=4 l=1] addhi3_clobber/0
next prev parent reply other threads:[~2023-02-23 15:44 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-03 0:33 [Bug c/97276] New: " tre at gmx dot de
2020-10-03 0:34 ` [Bug c/97276] " tre at gmx dot de
2023-02-23 13:31 ` [Bug target/97276] " gjl at gcc dot gnu.org
2023-02-23 13:56 ` tre at gmx dot de
2023-02-23 15:44 ` gjl at gcc dot gnu.org [this message]
2023-02-23 16:02 ` gjl at gcc dot gnu.org
2024-02-20 15:27 ` gjl at gcc dot gnu.org
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