Hi,
On 2021/5/18 15:02, Richard Biener wrote:
> Can you, for the new gcc.dg/tree-ssa/ssa-sink-18.c testcase, add
> a comment explaining what operations we expect to sink? The testcase
> is likely somewhat fragile in the exact number of sinkings
> (can you check on some other target and maybe P8BE with -m32 for
> example?), so for future adjustments it would be nice to easiliy
> figure out what we expect to happen.
>
> OK with that change.
Thanks a lot for the reminder! ssa-sink-18.c generates different code
for m32 and m64 exactly due to different type size conversion and ivopts
selection, since -m32 and -m64 couldn't co-exist in one test file, shall
I restrict it to -m64 only or check target lp64/target ilp32?
I've verified this case shows same behavior on X86, AArch64 and Power for
both m32 and m64.
-m32:
<bb 29> [local count: 75120046]:
# len_155 = PHI <len_127(28), len_182(55)>
len_182 = len_155 + 1;
_35 = (unsigned int) ip_249;
_36 = _35 + len_182;
_380 = (uint8_t *) _36;
if (maxlen_179 > len_182)
goto <bb 30>; [94.50%]
else
goto <bb 31>; [5.50%]
...
Sinking _329 = (uint8_t *) _36;
from bb 29 to bb 86
Sinking _36 = _35 + len_182;
from bb 29 to bb 86
Sinking _35 = (unsigned int) ip_249;
from bb 29 to bb 86
Pass statistics of "sink": ----------------
Sunk statements: 3
-m64:
<bb 29> [local count: 75120046]:
# ivtmp.23_34 = PHI <ivtmp.23_36(28), ivtmp.23_35(55)>
_38 = (unsigned int) ivtmp.23_34;
len_161 = _38 + 4294967295;
_434 = (unsigned long) ip_254;
_433 = ivtmp.23_34 + _434;
_438 = (uint8_t *) _433;
if (_38 < maxlen_187)
goto <bb 30>; [94.50%]
else
goto <bb 31>; [5.50%]
...
Sinking _367 = (uint8_t *) _320;
from bb 31 to bb 90
Sinking _320 = _321 + ivtmp.25_326;
from bb 31 to bb 90
Sinking _321 = (unsigned long) ip_229;
from bb 31 to bb 90
Sinking len_158 = _322 + 4294967295;
from bb 31 to bb 33
Pass statistics of "sink": ----------------
Sunk statements: 4
Regarding to the comments part:
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-sink-18.c
b/gcc/testsuite/gcc.dg/tree-ssa/ssa-sink-18.c
index 52b9a74b65f..5147f7b85cd 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/ssa-sink-18.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-sink-18.c
@@ -193,16 +193,17 @@ compute_on_bytes (uint8_t *in_data, int in_len, uint8_t
*out_data, int out_len)
return op - out_data;
}
+ /* For this case, pass sink2 sinks statements from hot loop header to loop
+ exits after gimple loop optimizations, which generates instructions
executed
+ each iteration in loop, but the results are used outside of loop:
+ With -m64,
+ "Sinking _367 = (uint8_t *) _320;
+ from bb 31 to bb 90
+ Sinking _320 = _321 + ivtmp.25_326;
+ from bb 31 to bb 90
+ Sinking _321 = (unsigned long) ip_229;
+ from bb 31 to bb 90
+ Sinking len_158 = _322 + 4294967295;
+ from bb 31 to bb 33" */
- /* { dg-final { scan-tree-dump-times "Sunk statements: 4" 1 "sink2" } } */
+ /* { dg-final { scan-tree-dump-times "Sunk statements: 4" 1 "sink2" { target
lp64 } } } */
+ /* { dg-final { scan-tree-dump-times "Sunk statements: 3" 1 "sink2" { target
ilp32 } } } */
--
Thanks,
Xionghu
