Prominent LEON2 chips like the AT697E and AT697F do not properly support
the FSMULD instruction. LEON3 targets using the GRFPU-lite floating
point unit do not support the FSMULD in hardware. Disable this
instruction for for all LEON/LEON3 targets for simplicity.
This leads to a code size increase and performance degradation on
GR712RC and GR740 targets. The code generation for the fmaf() function
of Newlib changes for example from
00000000 <fmaf>:
0: 9c 03 bf b0 add %sp, -80, %sp
4: d2 23 a0 4c st %o1, [ %sp + 0x4c ]
8: d1 03 a0 4c ld [ %sp + 0x4c ], %f8
c: d0 23 a0 4c st %o0, [ %sp + 0x4c ]
10: d3 03 a0 4c ld [ %sp + 0x4c ], %f9
14: d4 23 a0 4c st %o2, [ %sp + 0x4c ]
18: 81 a2 0d 29 fsmuld %f8, %f9, %f0
1c: d1 03 a0 4c ld [ %sp + 0x4c ], %f8
20: 91 a0 19 28 fstod %f8, %f8
24: 9c 03 a0 50 add %sp, 0x50, %sp
28: 81 a0 08 48 faddd %f0, %f8, %f0
2c: 81 c3 e0 08 retl
30: 81 a0 18 c0 fdtos %f0, %f0
to
00000000 <fmaf>:
0: 9c 03 bf b0 add %sp, -80, %sp
4: d0 23 a0 4c st %o0, [ %sp + 0x4c ]
8: d1 03 a0 4c ld [ %sp + 0x4c ], %f8
c: d2 23 a0 4c st %o1, [ %sp + 0x4c ]
10: 81 a0 19 28 fstod %f8, %f0
14: d1 03 a0 4c ld [ %sp + 0x4c ], %f8
18: 95 a0 19 28 fstod %f8, %f10
1c: d4 23 a0 4c st %o2, [ %sp + 0x4c ]
20: d1 03 a0 4c ld [ %sp + 0x4c ], %f8
24: 81 a0 09 4a fmuld %f0, %f10, %f0
28: 91 a0 19 28 fstod %f8, %f8
2c: 9c 03 a0 50 add %sp, 0x50, %sp
30: 81 a0 08 48 faddd %f0, %f8, %f0
34: 81 c3 e0 08 retl
38: 81 a0 18 c0 fdtos %f0, %f0
gcc/
* config/sparc/sparc.md (muldf3_extend): Disable for LEON/LEON3
targets.
---
gcc/config/sparc/sparc.md | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/gcc/config/sparc/sparc.md b/gcc/config/sparc/sparc.md
index b154003c54a..37b4b6e6884 100644
--- a/gcc/config/sparc/sparc.md
+++ b/gcc/config/sparc/sparc.md
@@ -6121,7 +6121,7 @@ visl")
[(set (match_operand:DF 0 "register_operand" "=e")
(mult:DF (float_extend:DF (match_operand:SF 1 "register_operand" "f"))
(float_extend:DF (match_operand:SF 2 "register_operand"
"f"))))]
- "(TARGET_V8 || TARGET_V9) && TARGET_FPU && !sparc_fix_ut699"
+ "(TARGET_V8 || TARGET_V9) && TARGET_FPU && !sparc_fix_ut699 && !TARGET_LEON
&& !TARGET_LEON3"
"fsmuld\t%1, %2, %0"
[(set_attr "type" "fpmul")
(set_attr "fptype" "double")])
--
2.12.3
