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re PR middle-end/45819 (unexpected unaligned access to volatile int) 

2011-07-22  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/45819
	* tree-ssa-forwprop.c (forward_propagate_addr_expr_1): Properly
	preserve volatile and notrap flags.

	* gcc.dg/pr45819.c: New testcase.

From-SVN: r176623
This commit is contained in:
Richard Guenther 2011-07-22 11:55:30 +00:00 committed by Richard Biener
parent 679debeea3
commit 27315aa68f
4 changed files with 37 additions and 2 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
2011-07-22 Richard Guenther <rguenther@suse.de>
PR tree-optimization/45819
* tree-ssa-forwprop.c (forward_propagate_addr_expr_1): Properly
preserve volatile and notrap flags.
2011-07-22 Rainer Orth <ro@CeBiTec.Uni-Bielefeld.DE>
Ralf Wildenhues <Ralf.Wildenhues@gmx.de>

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2011-07-22 Richard Guenther <rguenther@suse.de>
PR tree-optimization/45819
* gcc.dg/pr45819.c: New testcase.
2011-07-22 Uros Bizjak <ubizjak@gmail.com>
* lib/target-supports.exp (check_ifunc_available): Rewrite.

20
gcc/testsuite/gcc.dg/pr45819.c Normal file
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@ -0,0 +1,20 @@
/* { dg-do compile } */
/* { dg-options "-O2 -fdump-tree-optimized" } */
struct ehci_regs {
char x;
unsigned int port_status[0];
} __attribute__ ((packed));
struct ehci_hcd {
struct ehci_regs *regs;
};
int ehci_hub_control (struct ehci_hcd *ehci, int wIndex)
{
unsigned int *status_reg = &ehci->regs->port_status[wIndex];
return *(volatile unsigned int *)status_reg;
}
/* { dg-final { scan-tree-dump "={v}" "optimized" } } */
/* { dg-final { cleanup-tree-dump "optimized" } } */

8
gcc/tree-ssa-forwprop.c
View File

@ -875,6 +875,8 @@ forward_propagate_addr_expr_1 (tree name, tree def_rhs,
}
*def_rhs_basep = build2 (MEM_REF, TREE_TYPE (*def_rhs_basep),
new_base, new_offset);
TREE_THIS_VOLATILE (*def_rhs_basep) = TREE_THIS_VOLATILE (lhs);
TREE_THIS_NOTRAP (*def_rhs_basep) = TREE_THIS_NOTRAP (lhs);
gimple_assign_set_lhs (use_stmt,
unshare_expr (TREE_OPERAND (def_rhs, 0)));
*def_rhs_basep = saved;
@ -927,9 +929,9 @@ forward_propagate_addr_expr_1 (tree name, tree def_rhs,
tidy_after_forward_propagate_addr (use_stmt);
return res;
}
/* If the LHS is a plain dereference and the value type is the same as
/* If the RHS is a plain dereference and the value type is the same as
that of the pointed-to type of the address we can put the
dereferenced address on the LHS preserving the original alias-type. */
dereferenced address on the RHS preserving the original alias-type. */
else if (gimple_assign_rhs1 (use_stmt) == rhs
&& useless_type_conversion_p
(TREE_TYPE (gimple_assign_lhs (use_stmt)),
@ -954,6 +956,8 @@ forward_propagate_addr_expr_1 (tree name, tree def_rhs,
}
*def_rhs_basep = build2 (MEM_REF, TREE_TYPE (*def_rhs_basep),
new_base, new_offset);
TREE_THIS_VOLATILE (*def_rhs_basep) = TREE_THIS_VOLATILE (rhs);
TREE_THIS_NOTRAP (*def_rhs_basep) = TREE_THIS_NOTRAP (rhs);
gimple_assign_set_rhs1 (use_stmt,
unshare_expr (TREE_OPERAND (def_rhs, 0)));
*def_rhs_basep = saved;