| Summary: | [4.1 Regression] inliner creates an INDIRECT_REF without TREE_THIS_VOLATILE set for *a | ||
|---|---|---|---|
| Product: | gcc | Reporter: | Atsushi Nemoto <anemo> |
| Component: | tree-optimization | Assignee: | Not yet assigned to anyone <unassigned> |
| Status: | RESOLVED FIXED | ||
| Severity: | normal | CC: | gcc-bugs, hubicka, pinskia, rguenth, zadeck |
| Priority: | P3 | Keywords: | wrong-code |
| Version: | 4.2.0 | ||
| Target Milestone: | 4.1.1 | ||
| Host: | Target: | ||
| Build: | Known to work: | ||
| Known to fail: | 4.1.0 4.2.0 | Last reconfirmed: | 2006-04-21 12:50:39 |
From ipa-pure-const we get Function found to be pure: foo_read Function found to be pure: foo which is of course bogus for volatile pointer arguments. It's a regression, because ipa-pure-const is new. ipa-pure-const is just a symtom of the problem. TREE_THIS_VOLATILE is not set on the INDIRECT_REF. One more inliner fix:
Index: tree-inline.c
===================================================================
--- tree-inline.c (revision 112997)
+++ tree-inline.c (working copy)
@@ -590,6 +590,7 @@ copy_body_r (tree *tp, int *walk_subtree
if (n)
{
tree new;
+ tree old;
/* If we happen to get an ADDR_EXPR in n->value, strip
it manually here as we'll eventually get ADDR_EXPRs
which lie about their types pointed to. In this case
@@ -598,13 +599,17 @@ copy_body_r (tree *tp, int *walk_subtree
does other useful transformations, try that first, though. */
tree type = TREE_TYPE (TREE_TYPE ((tree)n->value));
new = unshare_expr ((tree)n->value);
+ old = *tp;
*tp = fold_indirect_ref_1 (type, new);
if (! *tp)
{
if (TREE_CODE (new) == ADDR_EXPR)
*tp = TREE_OPERAND (new, 0);
else
- *tp = build1 (INDIRECT_REF, type, new);
+ {
+ *tp = build1 (INDIRECT_REF, type, new);
+ TREE_THIS_VOLATILE (*tp) = TREE_THIS_VOLATILE (old);
+ }
}
*walk_subtrees = 0;
return NULL;
Bootstrapped and tested on x86_64-unknown-linux-gnu. Subject: Bug number PR27236 A patch for this bug has been added to the patch tracker. The mailing list url for the patch is http://gcc.gnu.org/ml/gcc-patches/2006-04/msg00871.html Note that I just figured out that your patch doesn't fix the problem. Subject: Bug 27236 Author: rguenth Date: Mon Apr 24 09:06:51 2006 New Revision: 113221 URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=113221 Log: 2006-04-24 Andrew Pinski <pinskia@gcc.gnu.org> Richard Guenther <rguenther@suse.de> PR tree-optimization/27236 * tree-inline.c (copy_body_r): Make sure to copy TREE_THIS_VOLATILE flag. * gcc.dg/tree-ssa/pr27236.c: New testcase. Added: trunk/gcc/testsuite/gcc.dg/tree-ssa/pr27236.c Modified: trunk/gcc/ChangeLog trunk/gcc/testsuite/ChangeLog trunk/gcc/tree-inline.c Uh, it did. Sorry. Fixed on the mainline. Subject: Bug 27236 Author: rguenth Date: Fri Apr 28 11:43:43 2006 New Revision: 113343 URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=113343 Log: 2006-04-28 Andrew Pinski <pinskia@gcc.gnu.org> Richard Guenther <rguenther@suse.de> PR middle-end/26869 * tree-complex.c (update_parameter_components): Don't handle unused parameters which have no default def. * gcc.dg/torture/pr26869.c: New testcase. PR tree-optimization/27236 * tree-inline.c (copy_body_r): Make sure to copy TREE_THIS_VOLATILE flag. * gcc.dg/tree-ssa/pr27236.c: New testcase. PR tree-optimization/27218 * tree-inline.c (expand_call_inline): Strip useless type conversions for the return slot address. * g++.dg/tree-ssa/pr27218.C: New testcase. Added: branches/gcc-4_1-branch/gcc/testsuite/g++.dg/tree-ssa/pr27218.C branches/gcc-4_1-branch/gcc/testsuite/gcc.dg/torture/pr26869.c - copied unchanged from r113219, trunk/gcc/testsuite/gcc.dg/torture/pr26869.c branches/gcc-4_1-branch/gcc/testsuite/gcc.dg/tree-ssa/pr27236.c - copied unchanged from r113221, trunk/gcc/testsuite/gcc.dg/tree-ssa/pr27236.c Modified: branches/gcc-4_1-branch/gcc/ChangeLog branches/gcc-4_1-branch/gcc/testsuite/ChangeLog branches/gcc-4_1-branch/gcc/tree-complex.c branches/gcc-4_1-branch/gcc/tree-inline.c Fixed. |
gcc 4.1.0 (and 4.2-20050415) produces wrong output for this program. I can reproduce it on i386 and mips/mipsel. Calls for foo_read() must not be discarded (for example, 'mem' might point a memory-mapped IO register), but gcc -O optimizes a foo_read() call away. gcc -O -fno-unit-at-a-time produces correct output. static inline int inline_read(volatile int *mem) { return *mem; } int foo_read(volatile int *mem) { return inline_read(mem); } unsigned int foo(volatile int *mem) { foo_read(mem); return foo_read(mem); } gcc -O output: .file "foo.c" .text .globl foo_read .type foo_read, @function foo_read: pushl %ebp movl %esp, %ebp movl 8(%ebp), %eax movl (%eax), %eax popl %ebp ret .size foo_read, .-foo_read .globl foo .type foo, @function foo: pushl %ebp movl %esp, %ebp subl $4, %esp movl 8(%ebp), %eax movl %eax, (%esp) call foo_read leave ret .size foo, .-foo .ident "GCC: (GNU) 4.1.0" .section .note.GNU-stack,"",@progbits gcc -O -fno-unit-at-a-time output: .file "foo.c" .text .globl foo_read .type foo_read, @function foo_read: pushl %ebp movl %esp, %ebp movl 8(%ebp), %eax movl (%eax), %eax popl %ebp ret .size foo_read, .-foo_read .globl foo .type foo, @function foo: pushl %ebp movl %esp, %ebp pushl %ebx subl $4, %esp movl 8(%ebp), %ebx movl %ebx, (%esp) call foo_read movl %ebx, (%esp) call foo_read addl $4, %esp popl %ebx popl %ebp ret .size foo, .-foo .ident "GCC: (GNU) 4.1.0" .section .note.GNU-stack,"",@progbits