Hi,
This patch sets TREE_READONLY on all non-static const and immutable
variables in D, as well as all static immutable variables that aren't
initialized by a module constructor. This allows more aggressive
constant folding of D code which makes use of `immutable' or `const'.
Bootstrapped and regression tested on x86_64-linux-gnu, committed to
mainline, and backported to releases/gcc-13 and releases/gcc-12.
Regards,
Iain.
---
PR d/110514
gcc/d/ChangeLog:
* decl.cc (get_symbol_decl): Set TREE_READONLY on certain kinds of
const and immutable variables.
* expr.cc (ExprVisitor::visit (ArrayLiteralExp *)): Set TREE_READONLY
on immutable dynamic array literals.
gcc/testsuite/ChangeLog:
* gdc.dg/pr110514a.d: New test.
* gdc.dg/pr110514b.d: New test.
* gdc.dg/pr110514c.d: New test.
* gdc.dg/pr110514d.d: New test.
---
gcc/d/decl.cc | 14 ++++++++++++++
gcc/d/expr.cc | 4 ++++
gcc/testsuite/gdc.dg/pr110514a.d | 9 +++++++++
gcc/testsuite/gdc.dg/pr110514b.d | 8 ++++++++
gcc/testsuite/gdc.dg/pr110514c.d | 8 ++++++++
gcc/testsuite/gdc.dg/pr110514d.d | 8 ++++++++
6 files changed, 51 insertions(+)
create mode 100644 gcc/testsuite/gdc.dg/pr110514a.d
create mode 100644 gcc/testsuite/gdc.dg/pr110514b.d
create mode 100644 gcc/testsuite/gdc.dg/pr110514c.d
create mode 100644 gcc/testsuite/gdc.dg/pr110514d.d
diff --git a/gcc/d/decl.cc b/gcc/d/decl.cc
index 78c4ab554dc..3f980851259 100644
--- a/gcc/d/decl.cc
+++ b/gcc/d/decl.cc
@@ -1277,6 +1277,20 @@ get_symbol_decl (Declaration *decl)
DECL_INITIAL (decl->csym) = build_expr (ie, true);
}
}
+
+ /* [type-qualifiers/const-and-immutable]
+
+ `immutable` applies to data that cannot change. Immutable data values,
+ once constructed, remain the same for the duration of the program's
+ execution. */
+ if (vd->isImmutable () && !vd->setInCtorOnly ())
+ TREE_READONLY (decl->csym) = 1;
+
+ /* `const` applies to data that cannot be changed by the const reference
+ to that data. It may, however, be changed by another reference to that
+ same data. */
+ if (vd->isConst () && !vd->isDataseg ())
+ TREE_READONLY (decl->csym) = 1;
}
/* Set the declaration mangled identifier if static. */
diff --git a/gcc/d/expr.cc b/gcc/d/expr.cc
index c6245ff5fc1..b7cec1327fd 100644
--- a/gcc/d/expr.cc
+++ b/gcc/d/expr.cc
@@ -2701,6 +2701,10 @@ public:
if (tb->ty == TY::Tarray)
ctor = d_array_value (type, size_int (e->elements->length), ctor);
+ /* Immutable data can be placed in rodata. */
+ if (tb->isImmutable ())
+ TREE_READONLY (decl) = 1;
+
d_pushdecl (decl);
rest_of_decl_compilation (decl, 1, 0);
}
diff --git a/gcc/testsuite/gdc.dg/pr110514a.d b/gcc/testsuite/gdc.dg/pr110514a.d
new file mode 100644
index 00000000000..46e370527d3
--- /dev/null
+++ b/gcc/testsuite/gdc.dg/pr110514a.d
@@ -0,0 +1,9 @@
+// { dg-do "compile" }
+// { dg-options "-O -fdump-tree-optimized" }
+immutable uint[] imm_arr = [1,2,3];
+int test_imm(immutable uint[] ptr)
+{
+ return imm_arr[2] == 3 ? 123 : 456;
+}
+// { dg-final { scan-assembler-not "_d_arraybounds_indexp" } }
+// { dg-final { scan-tree-dump "return 123;" optimized } }
diff --git a/gcc/testsuite/gdc.dg/pr110514b.d b/gcc/testsuite/gdc.dg/pr110514b.d
new file mode 100644
index 00000000000..86aeb485c34
--- /dev/null
+++ b/gcc/testsuite/gdc.dg/pr110514b.d
@@ -0,0 +1,8 @@
+// { dg-do "compile" }
+// { dg-options "-O" }
+immutable uint[] imm_ctor_arr;
+int test_imm_ctor(immutable uint[] ptr)
+{
+ return imm_ctor_arr[2] == 3;
+}
+// { dg-final { scan-assembler "_d_arraybounds_indexp" } }
diff --git a/gcc/testsuite/gdc.dg/pr110514c.d b/gcc/testsuite/gdc.dg/pr110514c.d
new file mode 100644
index 00000000000..94779e123a4
--- /dev/null
+++ b/gcc/testsuite/gdc.dg/pr110514c.d
@@ -0,0 +1,8 @@
+// { dg-do "compile" }
+// { dg-options "-O" }
+const uint[] cst_arr = [1,2,3];
+int test_cst(const uint[] ptr)
+{
+ return cst_arr[2] == 3;
+}
+// { dg-final { scan-assembler "_d_arraybounds_indexp" } }
diff --git a/gcc/testsuite/gdc.dg/pr110514d.d b/gcc/testsuite/gdc.dg/pr110514d.d
new file mode 100644
index 00000000000..56e9a3139ea
--- /dev/null
+++ b/gcc/testsuite/gdc.dg/pr110514d.d
@@ -0,0 +1,8 @@
+// { dg-do "compile" }
+// { dg-options "-O" }
+const uint[] cst_ctor_arr;
+int test_cst_ctor(const uint[] ptr)
+{
+ return cst_ctor_arr[2] == 3;
+}
+// { dg-final { scan-assembler "_d_arraybounds_indexp" } }
--
2.39.2
