Hi!
The s390 glibc (_itoa function in particular) is miscompiled because
pcom pass changes:
__asm__("lr %N0,%1
mr %0,%2" : "=&r" __x.__ll : "r" ti_10, "r" s1_12);
__w1_15 = __x.__i.__h;
into:
__x___i___h_lsm0.28_34 = __x.__i.__h;
...
__asm__("lr %N0,%1
mr %0,%2" : "=&r" __x.__ll : "r" ti_10, "r" s1_12);
__w1_15 = __x___i___h_lsm0.28_34;
(where __x is a non-addressable union var of a DImode __ll and a struct of
two SImode __i.__{l,h}. The problem is in get_references_in_stmt:
/* ASM_EXPR and CALL_EXPR may embed arbitrary side effects.
Calls have side-effects, except those to const or pure
functions. */
if ((stmt_code == GIMPLE_CALL
&& !(gimple_call_flags (stmt) & (ECF_CONST | ECF_PURE)))
|| (stmt_code == GIMPLE_ASM
&& gimple_asm_volatile_p (stmt)))
clobbers_memory = true;
is the only place where it handles asm (but the testcase doesn't have
it volatile) and otherwise ignores all the references.
Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux,
ok for trunk?
BTW, not sure about non-volatile asm that has memory clobber, maybe
the above snippet should be changed into:
|| (stmt_code == GIMPLE_ASM
&& (gimple_asm_volatile_p (stmt)
|| gimple_asm_clobbers_memory_p (stmt)))
2012-01-25 Jakub Jelinek <ja...@redhat.com>
PR tree-optimization/51987
* tree-data-ref.c (get_references_in_stmt): Handle references in
non-volatile GIMPLE_ASM.
* gcc.target/i386/pr51987.c: New test.
--- gcc/tree-data-ref.c.jj 2011-11-28 17:58:04.000000000 +0100
+++ gcc/tree-data-ref.c 2012-01-24 22:33:18.995077693 +0100
@@ -1,5 +1,5 @@
/* Data references and dependences detectors.
- Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011
+ Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012
Free Software Foundation, Inc.
Contributed by Sebastian Pop <p...@cri.ensmp.fr>
@@ -4226,6 +4226,35 @@ get_references_in_stmt (gimple stmt, VEC
}
}
}
+ else if (stmt_code == GIMPLE_ASM)
+ {
+ unsigned i;
+ /* Inputs may perform loads. */
+ for (i = 0; i < gimple_asm_ninputs (stmt); ++i)
+ {
+ op1 = &TREE_VALUE (gimple_asm_input_op (stmt, i));
+ if (DECL_P (*op1)
+ || (REFERENCE_CLASS_P (*op1) && get_base_address (*op1)))
+ {
+ ref = VEC_safe_push (data_ref_loc, heap, *references, NULL);
+ ref->pos = op1;
+ ref->is_read = true;
+ }
+ }
+ /* Outputs may perform stores. */
+ for (i = 0; i < gimple_asm_noutputs (stmt); ++i)
+ {
+ op0 = &TREE_VALUE (gimple_asm_output_op (stmt, i));
+ if (DECL_P (*op0)
+ || (REFERENCE_CLASS_P (*op0) && get_base_address (*op0)))
+ {
+ ref = VEC_safe_push (data_ref_loc, heap, *references, NULL);
+ ref->pos = op0;
+ ref->is_read = false;
+ }
+ }
+ return clobbers_memory;
+ }
else
return clobbers_memory;
--- gcc/testsuite/gcc.target/i386/pr51987.c.jj 2012-01-24 23:32:44.887896707
+0100
+++ gcc/testsuite/gcc.target/i386/pr51987.c 2012-01-24 23:34:26.289296794
+0100
@@ -0,0 +1,33 @@
+/* PR tree-optimization/51987 */
+/* { dg-do run { target { ! { ia32 } } } } */
+/* { dg-options "-O3" } */
+
+extern void abort (void);
+union U { unsigned long long l; struct { unsigned int l, h; } i; };
+
+__attribute__((noinline, noclone)) void
+foo (char *x, char *y)
+{
+ int i;
+ for (i = 0; i < 64; i++)
+ {
+ union U u;
+ asm ("movl %1, %k0; salq $32, %0" : "=r" (u.l) : "r" (i));
+ x[i] = u.i.h;
+ union U v;
+ asm ("movl %1, %k0; salq $32, %0" : "=r" (v.l) : "r" (i));
+ y[i] = v.i.h;
+ }
+}
+
+int
+main ()
+{
+ char a[64], b[64];
+ int i;
+ foo (a, b);
+ for (i = 0; i < 64; i++)
+ if (a[i] != i || b[i] != i)
+ abort ();
+ return 0;
+}
Jakub
