From: Georg Johann Lay <avr@gjlay.de>
To: gcc-patches@gcc.gnu.org
Cc: Jeff Law <jeffreyalaw@gmail.com>,
Senthil Kumar Selvaraj <saaadhu@gcc.gnu.org>
Subject: [patch,avr] Fix PR target/99184: Wrong cast from double to 16-bit and 32-bit ints.
Date: Sun, 18 Sep 2022 19:39:50 +0200 [thread overview]
Message-ID: <f4ae2f92-9ee2-ff9d-603a-d73c010a2fe3@gjlay.de> (raw)
[-- Attachment #1: Type: text/plain, Size: 1077 bytes --]
Hello,
this patch fixed PR target/99184 which incorrectly rounded during 64-bit
(long) double to 16-bit and 32-bit integers.
The patch just removes the respective roundings from
libf7-asm.sx::to_integer and ::to_unsigned. Luckily, LibF7 does nowhere
use respective functions internally, the only user is in libf7.c::f7_exp
which reads
f7_round (qq, qq);
int16_t q = f7_get_s16 (qq);
so that f7_get_s16() operates on an already rounded value, and therefore
this code works unaltered with or without rounding in to_integer.
The patch applies to directory
./libgcc/config/avr/libf7/
and is the same for all GCC versions v10+.
Please someone with write permissions commit it to trunk and backport to
v12, v11, and v10 as it is a wrong-code issue.
The patch will fit without problems (except for ChangeLog) because there
is no traffic on that folder.
Thanks, Johann
libgcc/config/avr/libf7/
PR target/99184
Remove rounding from double to [u]int16 and [u]int32 casts.
* libf7-asm.sx (to_integer, to_unsigned): Don't round 16-bit
and 32-bit integers.
[-- Attachment #2: pr99184.diff --]
[-- Type: text/x-patch, Size: 2035 bytes --]
diff --git a/ChangeLog b/ChangeLog
index 7e06f52..3ec0082 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+
+ PR target/99184
+ Remove rounding from double to [u]int16 and [u]int32 casts.
+
+ * libf7-asm.sx (to_integer, to_unsigned): Don't round 16-bit
+ and 32-bit integers.
+
2022-04-21 Release Manager
* GCC 11.3.0 released.
diff --git a/libf7-asm.sx b/libf7-asm.sx
index 7629e23..9d701f2 100644
--- a/libf7-asm.sx
+++ b/libf7-asm.sx
@@ -601,9 +601,6 @@ DEFUN to_integer
tst C6
brmi .Lsaturate.T ; > INTxx_MAX => saturate
- rcall .Lround
- brmi .Lsaturate.T ; > INTxx_MAX => saturate
-
brtc 9f ; >= 0 => return
sbrc Mask, 5
.global __negdi2
@@ -658,30 +655,6 @@ DEFUN to_integer
.global __clr_8
XJMP __clr_8
-.Lround:
- ;; C6.7 is known to be 0 here.
- ;; Return N = 1 iff we have to saturate.
- cpi Mask, 0xf
- breq .Lround16
- cpi Mask, 0x1f
- breq .Lround32
-
- ;; For now, no rounding in the 64-bit case. This rounding
- ;; would have to be integrated into the right-shift.
- cln
- ret
-
-.Lround32:
- rol C2
- adc C3, ZERO
- adc C4, ZERO
- rjmp 2f
-
-.Lround16:
- rol C4
-2: adc C5, ZERO
- adc C6, ZERO
- ret
ENDF to_integer
#endif /* F7MOD_to_integer_ */
@@ -725,29 +698,6 @@ DEFUN to_unsigned
clr CA
F7call lshrdi3
POP r16
-
- ;; Rounding
- ;; ??? C6.7 is known to be 0 here.
- cpi Mask, 0xf
- breq .Lround16
- cpi Mask, 0x1f
- breq .Lround32
-
- ;; For now, no rounding in the 64-bit case. This rounding
- ;; would have to be integrated into the right-shift.
- ret
-
-.Lround32:
- rol C2
- adc C3, ZERO
- adc C4, ZERO
- rjmp 2f
-
-.Lround16:
- rol C4
-2: adc C5, ZERO
- adc C6, ZERO
- brcs .Lset_0xffff ; Rounding overflow => saturate
ret
.Lset_0xffff:
next reply other threads:[~2022-09-18 17:40 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-18 17:39 Georg Johann Lay [this message]
2022-09-19 7:51 ` [patch, avr] " Richard Biener
2022-09-19 8:57 ` Georg Johann Lay
2022-09-19 9:06 ` Richard Biener
2022-09-19 14:58 ` Jonathan Wakely
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