From: Xi Ruoyao <xry111@xry111.site>
To: gcc-patches@gcc.gnu.org
Cc: Lulu Cheng <chenglulu@loongson.cn>, Wang Xuerui <i@xen0n.name>,
Chenghua Xu <xuchenghua@loongson.cn>,
Xi Ruoyao <xry111@xry111.site>
Subject: [PATCH] LoongArch: Use UNSPEC for fmin/fmax RTL pattern [PR105414]
Date: Sat, 24 Sep 2022 20:47:22 +0800 [thread overview]
Message-ID: <20220924124722.1946365-1-xry111@xry111.site> (raw)
I made a mistake defining fmin/fmax RTL patterns in r13-2085: I used
smin and smax in the definition mistakenly. This causes the optimizer
to perform constant folding as if fmin/fmax was "really" smin/smax
operations even with -fsignaling-nans. Then pr105414.c fails.
We don't have fmin/fmax RTL codes for now (PR107013) so we can only use
an UNSPEC for fmin and fmax patterns.
gcc/ChangeLog:
PR tree-optimization/105414
* config/loongarch/loongarch.md (UNSPEC_FMAX): New unspec.
(UNSPEC_FMIN): Likewise.
(fmax<mode>3): Use UNSPEC_FMAX instead of smax.
(fmin<mode>3): Use UNSPEC_FMIN instead of smin.
---
gcc/config/loongarch/loongarch.md | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/gcc/config/loongarch/loongarch.md b/gcc/config/loongarch/loongarch.md
index 3787fd8230f..214b14bddd3 100644
--- a/gcc/config/loongarch/loongarch.md
+++ b/gcc/config/loongarch/loongarch.md
@@ -35,6 +35,8 @@ (define_c_enum "unspec" [
;; Floating point unspecs.
UNSPEC_FRINT
UNSPEC_FCLASS
+ UNSPEC_FMAX
+ UNSPEC_FMIN
;; Override return address for exception handling.
UNSPEC_EH_RETURN
@@ -1032,8 +1034,9 @@ (define_insn "smin<mode>3"
(define_insn "fmax<mode>3"
[(set (match_operand:ANYF 0 "register_operand" "=f")
- (smax:ANYF (match_operand:ANYF 1 "register_operand" "f")
- (match_operand:ANYF 2 "register_operand" "f")))]
+ (unspec:ANYF [(use (match_operand:ANYF 1 "register_operand" "f"))
+ (use (match_operand:ANYF 2 "register_operand" "f"))]
+ UNSPEC_FMAX))]
""
"fmax.<fmt>\t%0,%1,%2"
[(set_attr "type" "fmove")
@@ -1041,8 +1044,9 @@ (define_insn "fmax<mode>3"
(define_insn "fmin<mode>3"
[(set (match_operand:ANYF 0 "register_operand" "=f")
- (smin:ANYF (match_operand:ANYF 1 "register_operand" "f")
- (match_operand:ANYF 2 "register_operand" "f")))]
+ (unspec:ANYF [(use (match_operand:ANYF 1 "register_operand" "f"))
+ (use (match_operand:ANYF 2 "register_operand" "f"))]
+ UNSPEC_FMIN))]
""
"fmin.<fmt>\t%0,%1,%2"
[(set_attr "type" "fmove")
--
2.37.0
next reply other threads:[~2022-09-24 12:47 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-24 12:47 Xi Ruoyao [this message]
2022-09-28 8:26 ` Lulu Cheng
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