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* [Bug tree-optimization/17147] New: Alignment information lost with variable size structures
@ 2004-08-23 11:17 falk at debian dot org
2004-11-04 15:34 ` [Bug tree-optimization/17147] " pinskia at gcc dot gnu dot org
0 siblings, 1 reply; 2+ messages in thread
From: falk at debian dot org @ 2004-08-23 11:17 UTC (permalink / raw)
To: gcc-bugs
Given this code:
int f(int n, void *p) {
struct {
int a[n];
int b[n];
} *sp = p;
return sp->b[5];
}
3.4 and 3.5 20040815 (ugh. I should probably try a newer one) generate:
s4addq $16,$17,$17
ldl $0,20($17)
while lno generates:
s4addq $16,$17,$17
lda $2,20($17)
ldq_u $3,20($17)
ldq_u $1,3($2)
extll $3,$2,$3
extlh $1,$2,$1
bis $3,$1,$0
addl $31,$0,$0
that is, it does an unaligned load. This does not happen at -O0.
--
Summary: Alignment information lost with variable size structures
Product: gcc
Version: lno
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: tree-optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: falk at debian dot org
CC: gcc-bugs at gcc dot gnu dot org
GCC build triplet: alphaev68-unknown-linux-gnu
GCC host triplet: alphaev68-unknown-linux-gnu
GCC target triplet: alphaev68-unknown-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17147
^ permalink raw reply [flat|nested] 2+ messages in thread
* [Bug tree-optimization/17147] Alignment information lost with variable size structures
2004-08-23 11:17 [Bug tree-optimization/17147] New: Alignment information lost with variable size structures falk at debian dot org
@ 2004-11-04 15:34 ` pinskia at gcc dot gnu dot org
0 siblings, 0 replies; 2+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2004-11-04 15:34 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2004-11-04 15:34 -------
The LNO branch is dead and it works correctly on the mainline.
--
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Keywords| |missed-optimization
Resolution| |WONTFIX
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17147
^ permalink raw reply [flat|nested] 2+ messages in thread
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2004-08-23 11:17 [Bug tree-optimization/17147] New: Alignment information lost with variable size structures falk at debian dot org
2004-11-04 15:34 ` [Bug tree-optimization/17147] " pinskia at gcc dot gnu dot org
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