--- /dev/null
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-pre-stats" } */
+
+#define REGISTER register
+
+#if defined __arm__
+# define REG1 asm("r4")
+#elif defined __i386__
+# define REG1 asm("ebx")
+#elif defined __mips__
+# define REG1 asm("s0")
+#elif defined __x86_64__
+# define REG1 asm("rbp")
+#else
+# undef REGISTER
+# define REGISTER
+# define REG1
+#endif
+
+REGISTER long data_0 REG1;
+long data_3;
+
+long foo(long data, long v)
+{
+ long i;
+ long t, u;
+
+ if (data)
+ i = data_0 + data_3;
+ else {
+ v = 2;
+ i = 5;
+ }
+ t = data_0 + data_3;
+ u = i;
+ return v * t * u;
+}
+/* We should not eliminate global register variable when it is the RHS of
+ a single assignment. */
+/* { dg-final { scan-tree-dump-times "Eliminated: 2" 1 "pre" { target { arm-*-* i?86-*-* mips*-*-* x86_64-*-* } } } } */
+/* { dg-final { scan-tree-dump-times "Eliminated: 3" 1 "pre" { target { ! { arm-*-* i?86-*-* mips*-*-* x86_64-*-* } } } } } */
+/* { dg-final { cleanup-tree-dump "pre" } } */
{
for (gsi = gsi_start_bb (b); !gsi_end_p (gsi); gsi_next (&gsi))
{
+ tree lhs = NULL_TREE;
+ tree rhs = NULL_TREE;
+
stmt = gsi_stmt (gsi);
+ if (gimple_has_lhs (stmt))
+ lhs = gimple_get_lhs (stmt);
+
+ if (gimple_assign_single_p (stmt))
+ rhs = gimple_assign_rhs1 (stmt);
+
/* Lookup the RHS of the expression, see if we have an
available computation for it. If so, replace the RHS with
- the available computation. */
+ the available computation.
+
+ See PR43491.
+ We don't replace global register variable when it is a the RHS of
+ a single assign. We do replace local register variable since gcc
+ does not guarantee local variable will be allocated in register. */
if (gimple_has_lhs (stmt)
- && TREE_CODE (gimple_get_lhs (stmt)) == SSA_NAME
+ && TREE_CODE (lhs) == SSA_NAME
&& !gimple_assign_ssa_name_copy_p (stmt)
&& (!gimple_assign_single_p (stmt)
- || !is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
+ || (!is_gimple_min_invariant (rhs)
+ && (gimple_assign_rhs_code (stmt) != VAR_DECL
+ || !is_global_var (rhs)
+ || !DECL_HARD_REGISTER (rhs))))
&& !gimple_has_volatile_ops (stmt)
- && !has_zero_uses (gimple_get_lhs (stmt)))
+ && !has_zero_uses (lhs))
{
- tree lhs = gimple_get_lhs (stmt);
- tree rhs = NULL_TREE;
tree sprime = NULL;
pre_expr lhsexpr = get_or_alloc_expr_for_name (lhs);
pre_expr sprimeexpr;
- if (gimple_assign_single_p (stmt))
- rhs = gimple_assign_rhs1 (stmt);
-
sprimeexpr = bitmap_find_leader (AVAIL_OUT (b),
get_expr_value_id (lhsexpr),
NULL);
dead. */
else if (gimple_assign_single_p (stmt)
&& !is_gimple_reg (gimple_assign_lhs (stmt))
- && (TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
- || is_gimple_min_invariant (gimple_assign_rhs1 (stmt))))
+ && (TREE_CODE (rhs) == SSA_NAME
+ || is_gimple_min_invariant (rhs)))
{
- tree rhs = gimple_assign_rhs1 (stmt);
tree val;
val = vn_reference_lookup (gimple_assign_lhs (stmt),
gimple_vuse (stmt), VN_WALK, NULL);