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* [gcc(refs/vendors/ibm/heads/perf)] sccvn: Fix handling of POINTER_PLUS_EXPR in memset offset [PR93582]
@ 2020-03-19 6:07 Jiu Fu Guo
0 siblings, 0 replies; only message in thread
From: Jiu Fu Guo @ 2020-03-19 6:07 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:fe19699ae2883b252d30f98481d32dabff00744b
commit fe19699ae2883b252d30f98481d32dabff00744b
Author: Jakub Jelinek <jakub@redhat.com>
Date: Thu Mar 5 08:00:04 2020 +0100
sccvn: Fix handling of POINTER_PLUS_EXPR in memset offset [PR93582]
> > where POINTER_PLUS_EXPR last operand has sizetype type, thus unsigned,
> > and in the testcase gimple_assign_rhs2 (def) is thus 0xf000000000000001ULL
> > which multiplied by 8 doesn't fit into signed HWI. If it would be treated
> > as signed offset instead, it would fit (-0xfffffffffffffffLL, multiplied
> > by 8 is -0x7ffffffffffffff8LL). Unfortunately with the poly_int obfuscation
> > I'm not sure how to convert it from unsigned to signed poly_int.
>
> mem_ref_offset provides a boiler-plate for this:
>
> poly_offset_int::from (wi::to_poly_wide (TREE_OPERAND (t, 1)), SIGNED);
Thanks, that seems to work.
The test now works on both big-endian and little-endian.
2020-03-05 Richard Biener <rguenther@suse.de>
Jakub Jelinek <jakub@redhat.com>
PR tree-optimization/93582
* tree-ssa-sccvn.c (vn_reference_lookup_3): Treat POINTER_PLUS_EXPR
last operand as signed when looking for memset offset. Formatting
fix.
* gcc.dg/tree-ssa/pr93582-11.c: New test.
Co-authored-by: Richard Biener <rguenther@suse.de>
Diff:
---
gcc/ChangeLog | 8 ++++++++
gcc/testsuite/ChangeLog | 5 +++++
gcc/testsuite/gcc.dg/tree-ssa/pr93582-11.c | 16 ++++++++++++++++
gcc/tree-ssa-sccvn.c | 12 ++++++++----
4 files changed, 37 insertions(+), 4 deletions(-)
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 5b2e4a83721..897c5986e8d 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+2020-03-05 Richard Biener <rguenther@suse.de>
+ Jakub Jelinek <jakub@redhat.com>
+
+ PR tree-optimization/93582
+ * tree-ssa-sccvn.c (vn_reference_lookup_3): Treat POINTER_PLUS_EXPR
+ last operand as signed when looking for memset offset. Formatting
+ fix.
+
2020-03-04 Andrew Pinski <apinski@marvell.com>
PR bootstrap/93962
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 95c8710800b..d4e7a3ac690 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2020-03-05 Jakub Jelinek <jakub@redhat.com>
+
+ PR tree-optimization/93582
+ * gcc.dg/tree-ssa/pr93582-11.c: New test.
+
2020-03-04 Martin Sebor <msebor@redhat.com>
PR c++/90938
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr93582-11.c b/gcc/testsuite/gcc.dg/tree-ssa/pr93582-11.c
new file mode 100644
index 00000000000..9ff400eff1d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr93582-11.c
@@ -0,0 +1,16 @@
+/* PR tree-optimization/93582 */
+/* { dg-do compile { target lp64 } } */
+/* { dg-options "-O2 -fdump-tree-fre1" } */
+/* { dg-final { scan-tree-dump "return 9223372036854775806;" "fre1" } } */
+
+union U { struct A { unsigned long long a : 1, b : 62, c : 1; } a; unsigned long long i; };
+
+unsigned long long
+foo (char *p)
+{
+ __builtin_memset (p - 0xfffffffffffffffULL, 0, 0xffffffffffffffeULL);
+ __builtin_memset (p + 1, 0, 0xffffffffffffffeULL);
+ union U *q = (union U *) (void *) (p - 4);
+ q->a.b = -1;
+ return q->i;
+}
diff --git a/gcc/tree-ssa-sccvn.c b/gcc/tree-ssa-sccvn.c
index 9ea30ef433c..b7174cd603f 100644
--- a/gcc/tree-ssa-sccvn.c
+++ b/gcc/tree-ssa-sccvn.c
@@ -2656,7 +2656,8 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *data_,
{
poly_int64 soff;
if (TREE_CODE (base) != MEM_REF
- || !(mem_ref_offset (base) << LOG2_BITS_PER_UNIT).to_shwi (&soff))
+ || !(mem_ref_offset (base)
+ << LOG2_BITS_PER_UNIT).to_shwi (&soff))
return (void *)-1;
offset += soff;
offset2 = 0;
@@ -2666,10 +2667,13 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *data_,
if (is_gimple_assign (def)
&& gimple_assign_rhs_code (def) == POINTER_PLUS_EXPR
&& gimple_assign_rhs1 (def) == TREE_OPERAND (base, 0)
- && poly_int_tree_p (gimple_assign_rhs2 (def))
- && (wi::to_poly_offset (gimple_assign_rhs2 (def))
- << LOG2_BITS_PER_UNIT).to_shwi (&offset2))
+ && poly_int_tree_p (gimple_assign_rhs2 (def)))
{
+ tree rhs2 = gimple_assign_rhs2 (def);
+ if (!(poly_offset_int::from (wi::to_poly_wide (rhs2),
+ SIGNED)
+ << LOG2_BITS_PER_UNIT).to_shwi (&offset2))
+ return (void *)-1;
ref2 = gimple_assign_rhs1 (def);
if (TREE_CODE (ref2) == SSA_NAME)
ref2 = SSA_VAL (ref2);
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2020-03-19 6:07 [gcc(refs/vendors/ibm/heads/perf)] sccvn: Fix handling of POINTER_PLUS_EXPR in memset offset [PR93582] Jiu Fu Guo
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