We've been essentially using find_taken_edge_switch_expr() in the
backward threader, but this is suboptimal because said function only
works with singletons. VRP has a much smarter find_case_label_range
that works with ranges.
Tested on x86-64 Linux with:
a) Bootstrap & regtests.
b) Verifying we get more threads than before.
c) Asserting that the new code catches everything the old one
code caught (over a set of bootstrap .ii files).
Committed as obvious.
gcc/ChangeLog:
* tree-ssa-threadbackward.c
(back_threader::find_taken_edge_switch): Use find_case_label_range
instead of find_taken_edge.
gcc/testsuite/ChangeLog:
* gcc.dg/tree-ssa/vrp106.c: Adjust for threading.
* gcc.dg/tree-ssa/vrp113.c: Same.
---
gcc/testsuite/gcc.dg/tree-ssa/vrp106.c | 4 ++--
gcc/testsuite/gcc.dg/tree-ssa/vrp113.c | 2 --
gcc/tree-ssa-threadbackward.c | 8 ++++----
3 files changed, 6 insertions(+), 8 deletions(-)
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/vrp106.c
b/gcc/testsuite/gcc.dg/tree-ssa/vrp106.c
index f25ea9c3826..dc5021a57b5 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/vrp106.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/vrp106.c
@@ -1,6 +1,6 @@
/* PR tree-optimization/18046 */
-/* { dg-options "-O2 -fdump-tree-vrp-thread1-details" } */
-/* { dg-final { scan-tree-dump-times "Threaded jump" 1 "vrp-thread1" } } */
+/* { dg-options "-O2 -fdump-tree-ethread-details" } */
+/* { dg-final { scan-tree-dump-times "Registering jump thread" 1 "ethread" } }
*/
/* During VRP we expect to thread the true arm of the conditional through the
switch
and to the BB that corresponds to the 7 ... 9 case label. */
extern void foo (void);
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/vrp113.c
b/gcc/testsuite/gcc.dg/tree-ssa/vrp113.c
index ab8d91e0f10..dfe4989d313 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/vrp113.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/vrp113.c
@@ -13,5 +13,3 @@ int f(int a) {
case 7: return 19;
}
}
-
-/* { dg-final { scan-tree-dump "return 3;" "vrp1" { xfail *-*-* } } } */
diff --git a/gcc/tree-ssa-threadbackward.c b/gcc/tree-ssa-threadbackward.c
index 6c1b15904ce..456effca5e1 100644
--- a/gcc/tree-ssa-threadbackward.c
+++ b/gcc/tree-ssa-threadbackward.c
@@ -195,11 +195,11 @@ back_threader::find_taken_edge_switch (const
vec<basic_block> &path,
if (r.varying_p ())
return NULL;
- tree val;
- if (r.singleton_p (&val))
- return ::find_taken_edge (gimple_bb (sw), val);
+ tree label = find_case_label_range (sw, &r);
+ if (!label)
+ return NULL;
- return NULL;
+ return find_edge (gimple_bb (sw), label_to_block (cfun, CASE_LABEL (label)));
}
// Same as find_taken_edge, but for paths ending in a GIMPLE_COND.
--
2.31.1
