From 6c9df5a0014040115ebe576c4c0b7914a0414422 Mon Sep 17 00:00:00 2001
From: Richard Guenther <rguenther@suse.de>
Date: Wed, 4 Jul 2012 12:10:40 +0000
Subject: [PATCH] re PR middle-end/53844 (GCC generates suboptimal code for
unused members of classes in some cases on multiple targets.)
2012-07-04 Richard Guenther <rguenther@suse.de>
PR tree-optimization/53844
* tree-ssa-dse.c (dse_possible_dead_store_p): Properly handle
the loop virtual PHI.
* g++.dg/tree-ssa/pr53844.C: New testcase.
From-SVN: r189256
---
gcc/ChangeLog | 6 ++
gcc/testsuite/ChangeLog | 5 ++
gcc/testsuite/g++.dg/tree-ssa/pr53844.C | 78 +++++++++++++++++++++++++
gcc/tree-ssa-dse.c | 12 +++-
4 files changed, 99 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/tree-ssa/pr53844.C
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 27c8cfcaa071..c33c5a5b4b04 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2012-07-04 Richard Guenther <rguenther@suse.de>
+
+ PR tree-optimization/53844
+ * tree-ssa-dse.c (dse_possible_dead_store_p): Properly handle
+ the loop virtual PHI.
+
2012-07-04 Richard Guenther <rguenther@suse.de>
PR tree-optimization/53849
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 884f66bfa4ec..3d1fda9e16ca 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2012-07-04 Richard Guenther <rguenther@suse.de>
+
+ PR tree-optimization/53844
+ * g++.dg/tree-ssa/pr53844.C: New testcase.
+
2012-07-04 Richard Guenther <rguenther@suse.de>
PR tree-optimization/53849
diff --git a/gcc/testsuite/g++.dg/tree-ssa/pr53844.C b/gcc/testsuite/g++.dg/tree-ssa/pr53844.C
new file mode 100644
index 000000000000..0be29d86cbfe
--- /dev/null
+++ b/gcc/testsuite/g++.dg/tree-ssa/pr53844.C
@@ -0,0 +1,78 @@
+// { dg-do compile }
+// { dg-options "-O2 -fdump-tree-optimized-vops" }
+
+struct VBase;
+
+//Very minimal numeric vector class where Base provides the policy
+template<typename Base=VBase>
+struct Vector : public Base{
+
+ inline Vector(const Base& b)
+ :Base(b)
+ {
+ }
+
+ //Assignment from any other sort of Vector
+ template<typename Base2>
+ void operator= (const Vector<Base2>& from)
+ {
+ for(int i=0; i<100; i++){
+ (*this)[i]=from[i];
+ }
+ }
+};
+
+
+//Base class to represent pointer as a Vector
+struct VBase{
+ double * const my_data;
+
+ double& operator[](int i) {
+ return my_data[i];
+ }
+
+ const double& operator[](int i) const {
+ return my_data[i];
+ }
+};
+
+//Base class providing very minimalistic expression template
+template<class B2> struct ScalarMulExpr
+{
+ const int& mul;
+ const Vector<B2>& vec;
+
+ int size() const
+ {
+ return vec.size();
+ }
+
+ double operator[](int i) const
+ {
+ return vec[i]*mul;
+ }
+
+ ScalarMulExpr(const Vector<B2>& vec_, const int& m)
+ :mul(m),vec(vec_)
+ {
+ }
+};
+
+//Allow vector to be multiplied by a scalar
+template<class B2>
+Vector<ScalarMulExpr<B2> > operator*(const Vector<B2>& lhs, const int& rhs)
+{
+ return ScalarMulExpr<B2>(lhs, rhs);
+}
+
+//Test function producing suboptimal asm code
+void test(const Vector<>& in, Vector<>& out, int i)
+{
+ out=in*1*1*1*1*1*1*1*1*1*1*1;
+}
+
+// There should be a single store remaining, inside the loops. All
+// dead stores to unused temporaries should have been removed.
+
+// { dg-final { scan-tree-dump-times "VDEF" 1 "optimized" } }
+// { dg-final { cleanup-tree-dump "optimized" } }
diff --git a/gcc/tree-ssa-dse.c b/gcc/tree-ssa-dse.c
index 5fdba8c543be..04cc6ad5009c 100644
--- a/gcc/tree-ssa-dse.c
+++ b/gcc/tree-ssa-dse.c
@@ -94,7 +94,7 @@ dse_possible_dead_store_p (gimple stmt, gimple *use_stmt)
temp = stmt;
do
{
- gimple use_stmt;
+ gimple use_stmt, defvar_def;
imm_use_iterator ui;
bool fail = false;
tree defvar;
@@ -108,6 +108,7 @@ dse_possible_dead_store_p (gimple stmt, gimple *use_stmt)
defvar = PHI_RESULT (temp);
else
defvar = gimple_vdef (temp);
+ defvar_def = temp;
temp = NULL;
FOR_EACH_IMM_USE_STMT (use_stmt, ui, defvar)
{
@@ -139,7 +140,14 @@ dse_possible_dead_store_p (gimple stmt, gimple *use_stmt)
fail = true;
BREAK_FROM_IMM_USE_STMT (ui);
}
- temp = use_stmt;
+ /* Do not consider the PHI as use if it dominates the
+ stmt defining the virtual operand we are processing,
+ we have processed it already in this case. */
+ if (gimple_bb (defvar_def) != gimple_bb (use_stmt)
+ && !dominated_by_p (CDI_DOMINATORS,
+ gimple_bb (defvar_def),
+ gimple_bb (use_stmt)))
+ temp = use_stmt;
}
/* If the statement is a use the store is not dead. */
else if (ref_maybe_used_by_stmt_p (use_stmt,
--
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