https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103432
Jan Hubicka <hubicka at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Ever confirmed|0 |1
Target Milestone|12.0 |---
Keywords|wrong-code |
Known to work|11.2.0 |
Status|UNCONFIRMED |ASSIGNED
Last reconfirmed| |2021-11-26
Assignee|unassigned at gcc dot gnu.org |hubicka at gcc dot
gnu.org
CC| |hubicka at gcc dot gnu.org
Component|ipa |tree-optimization
--- Comment #1 from Jan Hubicka <hubicka at gcc dot gnu.org> ---
It fails with
./xgcc -B ./ -O2 d.ii -fdbg-cnt=ipa_mod_ref_pta:189 -fdump-tree-all-details
-fdump-ipa-all-details
and works
./xgcc -B ./ -O2 d.ii -fdbg-cnt=ipa_mod_ref_pta:188 -fdump-tree-all-details
-fdump-ipa-all-details
The difference in optimized dump is:
int main ()
{
struct DCTFrom D.11418;
@@ -2805,12 +2810,7 @@
float x[4];
struct DCTTo D.11356;
struct DCTFrom D.11355;
- float _3;
- float _4;
- double _6;
struct FILE * stderr.3_8;
- double _9;
- struct FILE * stderr.4_11;
float _12;
float _13;
double _15;
@@ -2996,30 +2996,10 @@
{anonymous}::IDCT1DWrapper.constprop<4, 1, {anonymous}::DCTFrom,
{anonymous}::DCTTo> (&D.11400, &D.11356);
D.11400 ={v} {CLOBBER};
D.11356 ={v} {CLOBBER};
- _3 = out[2];
- _4 = _3 - 1.0e+0;
- actual_accuracy_5 = ABS_EXPR <_4>;
- if (actual_accuracy_5 > 9.999999974752427078783512115478515625e-7)
- goto <bb 11>; [0.04%]
- else
- goto <bb 12>; [99.96%]
-
- <bb 11> [local count: 429325]:
- _6 = (double) actual_accuracy_5;
stderr.3_8 = stderr;
- fprintf (stderr.3_8, "ERROR: Too low accuracy: exp=%f act=%f\n",
9.999999974752427078783512115478515625e-7, _6);
+ fprintf (stderr.3_8, "ERROR: Too low accuracy: exp=%f act=%f\n",
9.999999974752427078783512115478515625e-7, 1.0e+0);
exit (1);
- <bb 12> [local count: 1072883004]:
- _9 = (double) actual_accuracy_5;
- stderr.4_11 = stderr;
- fprintf (stderr.4_11, "OK: Good accuracy: exp=%f act=%f\n",
9.999999974752427078783512115478515625e-7, _9);
- x ={v} {CLOBBER};
- out ={v} {CLOBBER};
- coeffs ={v} {CLOBBER};
- scratch_space ={v} {CLOBBER};
- return 0;
-
}
And I suppose we are not expected to optimize out the "Good accuracy" message
:)
So it looks out is modified by {anonymous}::IDCT1DWrapper.constprop<4, 1,
{anonymous}::DCTFrom, {anonymous}::DCTTo> (&D.11400, &D.11356);
but for some reason ipa propagation gets no_indirect_clobber for param1. This
seems wrong since to->data is written to, so it is an indirect clobber.
I may be able to look more into this only tomorrow - it is bit late.
