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[PATCH 1/2] [SPARC] Prevent -mfix-ut699 from generating b2bst errata sequences
- From: Daniel Cederman <cederman at gaisler dot com>
- To: gcc-patches at gcc dot gnu dot org
- Cc: ebotcazou at adacore dot com, sebastian dot huber at embedded-brains dot de, daniel at gaisler dot com
- Date: Mon, 27 Nov 2017 11:04:34 +0100
- Subject: [PATCH 1/2] [SPARC] Prevent -mfix-ut699 from generating b2bst errata sequences
- Authentication-results: sourceware.org; auth=none
- Authorized-sender: cederman at gaisler dot com
- References: <20171127100435.6055-1-cederman@gaisler.com>
The sequence
st
fdivd / fsqrtd
std
was generated in some cases with -mfix-ut699 when there was
a st before the div/sqrt. This sequence could trigger the b2bst errata.
Now the following safe sequence is generated instead:
st
nop
fdivd / fsqrtd
std
gcc/ChangeLog:
2017-11-27 Martin Aberg <maberg@gaisler.com>
* config/sparc/sparc.md (divdf3_fix): Add NOP and adjust length
to prevent b2bst errata sequence.
(sqrtdf2_fix): Likewise.
---
gcc/config/sparc/sparc.md | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/gcc/config/sparc/sparc.md b/gcc/config/sparc/sparc.md
index 0e45509..18d77bb 100644
--- a/gcc/config/sparc/sparc.md
+++ b/gcc/config/sparc/sparc.md
@@ -6221,10 +6221,10 @@ visl")
(div:DF (match_operand:DF 1 "register_operand" "e")
(match_operand:DF 2 "register_operand" "e")))]
"TARGET_FPU && sparc_fix_ut699"
- "fdivd\t%1, %2, %0\n\tstd\t%0, [%%sp-8]\n\tnop"
+ "fdivd\t%1, %2, %0\n\tnop\n\tstd\t%0, [%%sp-8]\n\tnop"
[(set_attr "type" "fpdivd")
(set_attr "fptype" "double")
- (set_attr "length" "3")])
+ (set_attr "length" "4")])
(define_insn "divsf3"
[(set (match_operand:SF 0 "register_operand" "=f")
@@ -6473,10 +6473,10 @@ visl")
[(set (match_operand:DF 0 "register_operand" "=e")
(sqrt:DF (match_operand:DF 1 "register_operand" "e")))]
"TARGET_FPU && sparc_fix_ut699"
- "fsqrtd\t%1, %0\n\tstd\t%0, [%%sp-8]\n\tnop"
+ "fsqrtd\t%1, %0\n\tnop\n\tstd\t%0, [%%sp-8]\n\tnop"
[(set_attr "type" "fpsqrtd")
(set_attr "fptype" "double")
- (set_attr "length" "3")])
+ (set_attr "length" "4")])
(define_insn "sqrtsf2"
[(set (match_operand:SF 0 "register_operand" "=f")
--
2.9.3