Hi,
PR105459 exposes one issue in inline_call handling that when it
decides to copy FP flags from callee to caller and rebuild the
optimization node for caller fndecl, it's possible that the target
option node is also necessary to be rebuilt. Without updating
target option node early, it can make nodes share the same target
option node wrongly, later when we want to unshare it somewhere
(like in target hook) it can get unexpected results, like ICE on
uninitialized secondary member of target globals exposed in this PR.
Commit r12-3721 makes it get exact fp_expression info and causes
more optimization chances then exposes this issue. Commit r11-5855
introduces two target options to shadow flag_excess_precision and
flag_unsafe_math_optimizations and shows the need to rebuild target
node in inline_call when optimization node changes.
As commented in PR105459, I tried to postpone init_function_start
in cgraph_node::expand, but abandoned it since I thought it just
concealed the issue. And I also tried to adjust the target node
when current function switching, but failed since we get the NULL
cfun and fndecl in WPA phase.
Bootstrapped and regtested on x86_64-redhat-linux, powerpc64-linux-gnu
P8 and powerpc64le-linux-gnu P9.
Any thoughts? Is it OK for trunk?
BR,
Kewen
-----
PR tree-optimization/105459
gcc/ChangeLog:
* ipa-inline-transform.cc (inline_call): Rebuild target option node
once optimization node gets rebuilt.
gcc/testsuite/ChangeLog:
* gcc.dg/lto/pr105459_0.c: New test.
---
gcc/ipa-inline-transform.cc | 50 +++++++++++++++++++++++++--
gcc/testsuite/gcc.dg/lto/pr105459_0.c | 35 +++++++++++++++++++
2 files changed, 83 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/lto/pr105459_0.c
diff --git a/gcc/ipa-inline-transform.cc b/gcc/ipa-inline-transform.cc
index 07288e57c73..edba58377f4 100644
--- a/gcc/ipa-inline-transform.cc
+++ b/gcc/ipa-inline-transform.cc
@@ -52,6 +52,7 @@ along with GCC; see the file COPYING3. If not see
#include "ipa-modref.h"
#include "symtab-thunks.h"
#include "symtab-clones.h"
+#include "target.h"
int ncalls_inlined;
int nfunctions_inlined;
@@ -469,8 +470,53 @@ inline_call (struct cgraph_edge *e, bool update_original,
}
/* Reload global optimization flags. */
- if (reload_optimization_node && DECL_STRUCT_FUNCTION (to->decl) == cfun)
- set_cfun (cfun, true);
+ if (reload_optimization_node)
+ {
+ /* Only need to check and update target option node
+ when target_option_default_node is not NULL. */
+ if (target_option_default_node)
+ {
+ /* Save the current context for optimization and target option
+ node. */
+ tree old_optimize
+ = build_optimization_node (&global_options, &global_options_set);
+ tree old_target_opt
+ = build_target_option_node (&global_options, &global_options_set);
+
+ /* Restore optimization with new optimizatin node. */
+ tree new_optimize = DECL_FUNCTION_SPECIFIC_OPTIMIZATION (to->decl);
+ if (old_optimize != new_optimize)
+ cl_optimization_restore (&global_options, &global_options_set,
+ TREE_OPTIMIZATION (new_optimize));
+
+ /* Restore target option with the one from caller fndecl. */
+ tree cur_target_opt = DECL_FUNCTION_SPECIFIC_TARGET (to->decl);
+ if (!cur_target_opt)
+ cur_target_opt = target_option_default_node;
+ cl_target_option_restore (&global_options, &global_options_set,
+ TREE_TARGET_OPTION (cur_target_opt));
+
+ /* Update target option as optimization changes. */
+ targetm.target_option.override ();
+
+ /* Rebuild target option node for caller fndecl and replace
+ with it if the node changes. */
+ tree new_target_opt
+ = build_target_option_node (&global_options, &global_options_set);
+ if (cur_target_opt != new_target_opt)
+ DECL_FUNCTION_SPECIFIC_TARGET (to->decl) = new_target_opt;
+
+ /* Restore the context with previous saved nodes. */
+ if (old_optimize != new_optimize)
+ cl_optimization_restore (&global_options, &global_options_set,
+ TREE_OPTIMIZATION (old_optimize));
+ cl_target_option_restore (&global_options, &global_options_set,
+ TREE_TARGET_OPTION (old_target_opt));
+ }
+
+ if (DECL_STRUCT_FUNCTION (to->decl) == cfun)
+ set_cfun (cfun, true);
+ }
/* If aliases are involved, redirect edge to the actual destination and
possibly remove the aliases. */
diff --git a/gcc/testsuite/gcc.dg/lto/pr105459_0.c
b/gcc/testsuite/gcc.dg/lto/pr105459_0.c
new file mode 100644
index 00000000000..c799e6ef23d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/lto/pr105459_0.c
@@ -0,0 +1,35 @@
+/* { dg-lto-do link } */
+/* { dg-lto-options { { -flto -O1 } } } */
+
+double m;
+int n;
+
+__attribute__ ((optimize ("-funsafe-math-optimizations")))
+void
+bar (int x)
+{
+ n = x;
+ m = n;
+}
+
+__attribute__ ((flatten))
+void
+foo (int x)
+{
+ bar (x);
+}
+
+void
+quux (void)
+{
+ ++n;
+}
+
+int
+main (void)
+{
+ foo (0);
+ quux ();
+
+ return 0;
+}
--
2.27.0
