http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50819
Ira Rosen <irar at il dot ibm.com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |ASSIGNED
Last reconfirmed| |2011-10-22
CC| |irar at il dot ibm.com
AssignedTo|unassigned at gcc dot |irar at gcc dot gnu.org
|gnu.org |
Ever Confirmed|0 |1
--- Comment #1 from Ira Rosen <irar at il dot ibm.com> 2011-10-22 12:25:30 UTC
---
SLP data dependence analysis checks that all the loads are before all the
stores in the basic block, and for sum1 we get
res_4(D)->theX = D.2306_31;
D.2305_32 = res_4(D)->theY;
D.2303_34 = D.2289_26 + D.2305_32;
res_4(D)->theY = D.2303_34;
D.2302_35 = res_4(D)->theZ;
D.2300_37 = D.2287_24 + D.2302_35;
res_4(D)->theZ = D.2300_37;
D.2299_38 = res_4(D)->theT;
D.2297_40 = D.2285_22 + D.2299_38;
res_4(D)->theT = D.2297_40;
while for sum2 the loads and stores are not mixed:
D.2391_29 = MEM[(const struct LorentzVector &)res_4(D)].theT;
D.2389_31 = D.2365_22 + D.2391_29;
D.2388_32 = MEM[(const struct LorentzVector &)res_4(D)].theZ;
D.2386_34 = D.2367_24 + D.2388_32;
D.2385_35 = MEM[(const struct LorentzVector &)res_4(D)].theY;
D.2383_37 = D.2369_26 + D.2385_35;
D.2382_38 = MEM[(const struct LorentzVector &)res_4(D)].theX;
D.2380_40 = D.2371_28 + D.2382_38;
res_4(D)->theX = D.2380_40;
res_4(D)->theY = D.2383_37;
res_4(D)->theZ = D.2386_34;
res_4(D)->theT = D.2389_31;
The attached patch relaxes the above check a bit. Since we go through all the
ddrs anyway, we can check the order between the loads and the stores in
vect_analyze_data_ref_dependence. We don't care about independent load-store
pairs, so we only need to add this check to the pairs with unknown dependence.
(Known dependencies are already checked in vect_drs_dependent_in_basic_block).
