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* [gcc r12-8246] Retain existing range knowledge when prefilling statements.
@ 2022-04-25 13:59 Andrew Macleod
0 siblings, 0 replies; only message in thread
From: Andrew Macleod @ 2022-04-25 13:59 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:362e2a9c6297203bcf7f66bfb51dffb82b42d3b3
commit r12-8246-g362e2a9c6297203bcf7f66bfb51dffb82b42d3b3
Author: Andrew MacLeod <amacleod@redhat.com>
Date: Mon Apr 25 09:56:35 2022 -0400
Retain existing range knowledge when prefilling statements.
When range_of_stmt was adjusted to avoid large recursion depth, we need to
intersect the calculated range whth the any known range to avoid losing
info. Range_of_stmt does this, but the new prefill code missed it.
PR tree-optimization/105276
gcc/
* gimple-range.cc (gimple_ranger::prefill_stmt_dependencies): Include
existing global range with calculated value.
gcc/testsuite/
* g++.dg/pr105276.C: New.
Diff:
---
gcc/gimple-range.cc | 4 ++++
gcc/testsuite/g++.dg/pr105276.C | 18 ++++++++++++++++++
2 files changed, 22 insertions(+)
diff --git a/gcc/gimple-range.cc b/gcc/gimple-range.cc
index 04075a98a80..f0caefce2a3 100644
--- a/gcc/gimple-range.cc
+++ b/gcc/gimple-range.cc
@@ -394,6 +394,10 @@ gimple_ranger::prefill_stmt_dependencies (tree ssa)
// Fold and save the value for NAME.
stmt = SSA_NAME_DEF_STMT (name);
fold_range_internal (r, stmt, name);
+ // Make sure we don't lose any current global info.
+ int_range_max tmp;
+ m_cache.get_global_range (tmp, name);
+ r.intersect (tmp);
m_cache.set_global_range (name, r);
}
continue;
diff --git a/gcc/testsuite/g++.dg/pr105276.C b/gcc/testsuite/g++.dg/pr105276.C
new file mode 100644
index 00000000000..ad0e9dd7e09
--- /dev/null
+++ b/gcc/testsuite/g++.dg/pr105276.C
@@ -0,0 +1,18 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+bool
+foo(unsigned i)
+{
+ bool result = true;
+ while (i)
+ {
+ i = i % 3;
+ i = i - (i == 2 ? 2 : i ? 1 : 0);
+ result = !result;
+ }
+ return result;
+}
+
+/* We should be able to eliminate the i - operation. */
+/* { dg-final { scan-tree-dump-not "i_.* - " "optimized" } } */
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