Having a value in the wrong mode is not the only hazard that users of
set_unique_reg_note should anticipate; it could also be that the value
is computed as a constant by the compiler, and thus the last instruction
obtained with get_last_insn is completely (or somewhat) unrelated; or an
expander could decide to save / restore some hard register around the
actual operation.
So, in general, the test should be if the candidate insn actually sets the
expected target. There are already a number of users of set_unique_reg_note
that do that. Others assume that a move, add or other expander emits a
single insn, or a sequence of insns that ends with a single insn, which
sets the target. Although that is often the case, this is not a safe
assumption to make. Fixing all these places with inlined code would
mean a lot of cut & paste programming. So instead, I've added a new
wrapper for set_unique_reg_note to be used in these circumstances, and
also used it to replace the existing inlined checks unless something special
was going on (e.g. testing two different target / value pairs).
Bootstrapped and regression tested on x86_64-unknown-linux-gnu.
2011-12-07 Joern Rennecke <joern.renne...@embecosm.com>
PR middle-end/40154
* emit-rtl.c (set_dst_reg_note): New function.
* rtl.h (set_dst_reg_note): Declare.
* optabs.c (expand_binop, expand_absneg_bit): Use set_dst_reg_note.
(emit_libcall_block, expand_fix): Likewise.
* function.c (assign_parm_setup_reg, expand_function_start): Likewise.
* expmed.c (expand_mult_const, expand_divmod): Likewise.
* reload1.c (gen_reload): Likewise.
Index: optabs.c
===================================================================
--- optabs.c (revision 182075)
+++ optabs.c (working copy)
@@ -2052,11 +2052,11 @@ expand_binop (enum machine_mode mode, op
{
rtx temp = emit_move_insn (target, xtarget);
- set_unique_reg_note (temp,
- REG_EQUAL,
- gen_rtx_fmt_ee (binoptab->code, mode,
- copy_rtx (xop0),
- copy_rtx (xop1)));
+ set_dst_reg_note (temp, REG_EQUAL,
+ gen_rtx_fmt_ee (binoptab->code, mode,
+ copy_rtx (xop0),
+ copy_rtx (xop1)),
+ target);
}
else
target = xtarget;
@@ -2104,11 +2104,12 @@ expand_binop (enum machine_mode mode, op
if (optab_handler (mov_optab, mode) != CODE_FOR_nothing)
{
temp = emit_move_insn (target ? target : product, product);
- set_unique_reg_note (temp,
- REG_EQUAL,
- gen_rtx_fmt_ee (MULT, mode,
- copy_rtx (op0),
- copy_rtx (op1)));
+ set_dst_reg_note (temp,
+ REG_EQUAL,
+ gen_rtx_fmt_ee (MULT, mode,
+ copy_rtx (op0),
+ copy_rtx (op1)),
+ target ? target : product);
}
return product;
}
@@ -2966,8 +2967,9 @@ expand_absneg_bit (enum rtx_code code, e
gen_lowpart (imode, target), 1, OPTAB_LIB_WIDEN);
target = lowpart_subreg_maybe_copy (mode, temp, imode);
- set_unique_reg_note (get_last_insn (), REG_EQUAL,
- gen_rtx_fmt_e (code, mode, copy_rtx (op0)));
+ set_dst_reg_note (get_last_insn (), REG_EQUAL,
+ gen_rtx_fmt_e (code, mode, copy_rtx (op0)),
+ target);
}
return target;
@@ -3899,8 +3901,7 @@ emit_libcall_block (rtx insns, rtx targe
}
last = emit_move_insn (target, result);
- if (optab_handler (mov_optab, GET_MODE (target)) != CODE_FOR_nothing)
- set_unique_reg_note (last, REG_EQUAL, copy_rtx (equiv));
+ set_dst_reg_note (last, REG_EQUAL, copy_rtx (equiv), target);
if (final_dest != target)
emit_move_insn (final_dest, target);
@@ -5213,11 +5214,10 @@ expand_fix (rtx to, rtx from, int unsign
{
/* Make a place for a REG_NOTE and add it. */
insn = emit_move_insn (to, to);
- set_unique_reg_note (insn,
- REG_EQUAL,
- gen_rtx_fmt_e (UNSIGNED_FIX,
- GET_MODE (to),
- copy_rtx (from)));
+ set_dst_reg_note (insn, REG_EQUAL,
+ gen_rtx_fmt_e (UNSIGNED_FIX, GET_MODE (to),
+ copy_rtx (from)),
+ to);
}
return;
Index: function.c
===================================================================
--- function.c (revision 182075)
+++ function.c (working copy)
@@ -3140,9 +3140,8 @@ assign_parm_setup_reg (struct assign_par
set_unique_reg_note (sinsn, REG_EQUIV, stackr);
}
}
- else if ((set = single_set (linsn)) != 0
- && SET_DEST (set) == parmreg)
- set_unique_reg_note (linsn, REG_EQUIV, equiv_stack_parm);
+ else
+ set_dst_reg_note (linsn, REG_EQUIV, equiv_stack_parm, parmreg);
}
/* For pointer data type, suggest pointer register. */
@@ -4757,7 +4756,7 @@ expand_function_start (tree subr)
/* Mark the register as eliminable, similar to parameters. */
if (MEM_P (chain)
&& reg_mentioned_p (arg_pointer_rtx, XEXP (chain, 0)))
- set_unique_reg_note (insn, REG_EQUIV, chain);
+ set_dst_reg_note (insn, REG_EQUIV, chain, local);
}
/* If the function receives a non-local goto, then store the
Index: expmed.c
===================================================================
--- expmed.c (revision 182075)
+++ expmed.c (working copy)
@@ -2939,6 +2939,7 @@ expand_mult_const (enum machine_mode mod
&& !optimize)
? target : 0;
rtx accum_target = optimize ? 0 : accum;
+ rtx accum_inner;
switch (alg->op[opno])
{
@@ -3004,16 +3005,18 @@ expand_mult_const (enum machine_mode mod
that. */
tem = op0, nmode = mode;
+ accum_inner = accum;
if (GET_CODE (accum) == SUBREG)
{
- nmode = GET_MODE (SUBREG_REG (accum));
+ accum_inner = SUBREG_REG (accum);
+ nmode = GET_MODE (accum_inner);
tem = gen_lowpart (nmode, op0);
}
insn = get_last_insn ();
- set_unique_reg_note (insn, REG_EQUAL,
- gen_rtx_MULT (nmode, tem,
- GEN_INT (val_so_far)));
+ set_dst_reg_note (insn, REG_EQUAL,
+ gen_rtx_MULT (nmode, tem, GEN_INT (val_so_far)),
+ accum_inner);
}
if (variant == negate_variant)
@@ -3823,7 +3826,7 @@ expand_divmod (int rem_flag, enum tree_c
rtx quotient = 0, remainder = 0;
rtx last;
int size;
- rtx insn, set;
+ rtx insn;
optab optab1, optab2;
int op1_is_constant, op1_is_pow2 = 0;
int max_cost, extra_cost;
@@ -4127,12 +4130,10 @@ expand_divmod (int rem_flag, enum tree_c
break;
insn = get_last_insn ();
- if (insn != last
- && (set = single_set (insn)) != 0
- && SET_DEST (set) == quotient)
- set_unique_reg_note (insn,
- REG_EQUAL,
- gen_rtx_UDIV (compute_mode, op0, op1));
+ if (insn != last)
+ set_dst_reg_note (insn, REG_EQUAL,
+ gen_rtx_UDIV (compute_mode, op0, op1),
+ quotient);
}
else /* TRUNC_DIV, signed */
{
@@ -4211,18 +4212,15 @@ expand_divmod (int rem_flag, enum tree_c
{
insn = get_last_insn ();
if (insn != last
- && (set = single_set (insn)) != 0
- && SET_DEST (set) == quotient
&& abs_d < ((unsigned HOST_WIDE_INT) 1
<< (HOST_BITS_PER_WIDE_INT - 1)))
- set_unique_reg_note (insn,
- REG_EQUAL,
- gen_rtx_DIV (compute_mode,
- op0,
- GEN_INT
- (trunc_int_for_mode
+ set_dst_reg_note (insn, REG_EQUAL,
+ gen_rtx_DIV (compute_mode, op0,
+ GEN_INT
+ (trunc_int_for_mode
(abs_d,
- compute_mode))));
+ compute_mode))),
+ quotient);
quotient = expand_unop (compute_mode, neg_optab,
quotient, quotient, 0);
@@ -4309,12 +4307,10 @@ expand_divmod (int rem_flag, enum tree_c
break;
insn = get_last_insn ();
- if (insn != last
- && (set = single_set (insn)) != 0
- && SET_DEST (set) == quotient)
- set_unique_reg_note (insn,
- REG_EQUAL,
- gen_rtx_DIV (compute_mode, op0, op1));
+ if (insn != last)
+ set_dst_reg_note (insn, REG_EQUAL,
+ gen_rtx_DIV (compute_mode, op0, op1),
+ quotient);
}
break;
}
@@ -4732,11 +4728,10 @@ expand_divmod (int rem_flag, enum tree_c
NULL_RTX, 1);
insn = get_last_insn ();
- set_unique_reg_note (insn,
- REG_EQUAL,
- gen_rtx_fmt_ee (unsignedp ? UDIV : DIV,
- compute_mode,
- op0, op1));
+ set_dst_reg_note (insn, REG_EQUAL,
+ gen_rtx_fmt_ee (unsignedp ? UDIV : DIV,
+ compute_mode, op0, op1),
+ quotient);
}
break;
Index: emit-rtl.c
===================================================================
--- emit-rtl.c (revision 182075)
+++ emit-rtl.c (working copy)
@@ -5004,6 +5004,17 @@ set_unique_reg_note (rtx insn, enum reg_
return REG_NOTES (insn);
}
+
+/* Like set_unique_reg_note, but don't do anything unless INSN sets DST. */
+rtx
+set_dst_reg_note (rtx insn, enum reg_note kind, rtx datum, rtx dst)
+{
+ rtx set = single_set (insn);
+
+ if (set && SET_DEST (set) == dst)
+ return set_unique_reg_note (insn, kind, datum);
+ return NULL_RTX;
+}
/* Return an indication of which type of insn should have X as a body.
The value is CODE_LABEL, INSN, CALL_INSN or JUMP_INSN. */
Index: rtl.h
===================================================================
--- rtl.h (revision 182075)
+++ rtl.h (working copy)
@@ -1893,6 +1893,7 @@ extern enum machine_mode choose_hard_reg
/* In emit-rtl.c */
extern rtx set_unique_reg_note (rtx, enum reg_note, rtx);
+extern rtx set_dst_reg_note (rtx, enum reg_note, rtx, rtx);
extern void set_insn_deleted (rtx);
/* Functions in rtlanal.c */
Index: reload1.c
===================================================================
--- reload1.c (revision 182075)
+++ reload1.c (working copy)
@@ -8574,7 +8574,7 @@ gen_reload (rtx out, rtx in, int opnum,
if (insn)
{
/* Add a REG_EQUIV note so that find_equiv_reg can find it. */
- set_unique_reg_note (insn, REG_EQUIV, in);
+ set_dst_reg_note (insn, REG_EQUIV, in, out);
return insn;
}
@@ -8584,7 +8584,7 @@ gen_reload (rtx out, rtx in, int opnum,
gcc_assert (!reg_overlap_mentioned_p (out, op0));
gen_reload (out, op1, opnum, type);
insn = emit_insn (gen_add2_insn (out, op0));
- set_unique_reg_note (insn, REG_EQUIV, in);
+ set_dst_reg_note (insn, REG_EQUIV, in, out);
}
#ifdef SECONDARY_MEMORY_NEEDED
