VRP no longer (since 4.1.2 at least) can optimize vrp06.c in one go
because we happen to chose a symbolic range when
Intersecting
[j_12(D), j_12(D)] EQUIVALENCES: { i_9(D) j_12(D) i_24 i_26 } (4
elements)
and
[10, 30] EQUIVALENCES: { i_9(D) i_26 } (2 elements)
to
[j_12(D), j_12(D)] EQUIVALENCES: { i_9(D) j_12(D) i_24 i_26 } (4
elements)
that pessimizes further refinement of ranges which happens
without looking at equivalences. We also seem to not consider
equivalences when folding predicates during propagation (anyone
can create a regression testcase out of that now? we really
should do that), thus it's important to choose [10, 30] above
to be able to fold the following < 0 test.
Bootstrap and regtest pending on x86_64-unknown-linux-gnu.
Richard.
2013-01-11 Richard Biener <rguent...@suse.de>
PR tree-optimization/55936
* tree-vrp.c (intersect_ranges): As fallback choose the
range we can easiest refine further.
* gcc.dg/tree-ssa/vrp06.c: Adjust.
Index: gcc/tree-vrp.c
===================================================================
*** gcc/tree-vrp.c (revision 195103)
--- gcc/tree-vrp.c (working copy)
*************** intersect_ranges (enum value_range_type
*** 7782,7791 ****
else
gcc_unreachable ();
}
!
! /* As a fallback simply use { *VRTYPE, *VR0MIN, *VR0MAX } as
! result for the intersection. That's always a conservative
! correct estimate. */
return;
}
--- 7782,7804 ----
else
gcc_unreachable ();
}
! else
! {
! /* As a fallback simply use the range that is closest to
! an integer constant range. That's always a conservative
! correct estimate. */
! if (((TREE_CODE (*vr0min) == INTEGER_CST)
! + (TREE_CODE (*vr0max) == INTEGER_CST)
! + (*vr0type == VR_RANGE))
! < ((TREE_CODE (vr1min) == INTEGER_CST)
! + (TREE_CODE (vr1max) == INTEGER_CST)
! + (vr1type == VR_RANGE)))
! {
! *vr0type = vr1type;
! *vr0min = vr1min;
! *vr0max = vr1max;
! }
! }
return;
}
Index: gcc/testsuite/gcc.dg/tree-ssa/vrp06.c
===================================================================
*** gcc/testsuite/gcc.dg/tree-ssa/vrp06.c (revision 195103)
--- gcc/testsuite/gcc.dg/tree-ssa/vrp06.c (working copy)
*************** foo (int i, int j, int a)
*** 27,31 ****
/* { dg-final { scan-tree-dump-times "Folding predicate i_\[0-9\]+.*0 to 0" 1
"vrp1" } } */
/* { dg-final { scan-tree-dump-times "Folding predicate j_\[0-9\]+.*0 to 1" 1
"vrp1" } } */
! /* { dg-final { scan-tree-dump-times "Folding predicate
i_\[0-9]+.*j_\[0-9\]+.* to 0" 1 "vrp1" { xfail *-*-* } } } */
/* { dg-final { cleanup-tree-dump "vrp1" } } */
--- 27,31 ----
/* { dg-final { scan-tree-dump-times "Folding predicate i_\[0-9\]+.*0 to 0" 1
"vrp1" } } */
/* { dg-final { scan-tree-dump-times "Folding predicate j_\[0-9\]+.*0 to 1" 1
"vrp1" } } */
! /* { dg-final { scan-tree-dump-times "Folding predicate
i_\[0-9]+.*j_\[0-9\]+.* to 0" 1 "vrp1" } } */
/* { dg-final { cleanup-tree-dump "vrp1" } } */
