This patch uses subreg_lowpart_offset in places that open-coded
the calculation. It also uses it in regcprop.c to test whether,
after a mode change, the first register in a multi-register group
is still the right one.
Tested on aarch64-linux-gnu and x86_64-linux-gnu, and by making sure
that there were no differences in testsuite assembly output for one
target per CPU. OK to install?
Richard
2017-08-23 Richard Sandiford <richard.sandif...@linaro.org>
Alan Hayward <alan.hayw...@arm.com>
David Sherwood <david.sherw...@arm.com>
gcc/
* calls.c (expand_call): Use subreg_lowpart_offset.
* cse.c (cse_insn): Likewise.
* regcprop.c (copy_value): Likewise.
(copyprop_hardreg_forward_1): Likewise.
Index: gcc/calls.c
===================================================================
--- gcc/calls.c 2017-08-21 15:49:31.653164829 +0100
+++ gcc/calls.c 2017-08-23 10:46:06.552151584 +0100
@@ -4128,7 +4128,6 @@ expand_call (tree exp, rtx target, int i
{
tree type = rettype;
int unsignedp = TYPE_UNSIGNED (type);
- int offset = 0;
machine_mode pmode;
/* Ensure we promote as expected, and get the new unsignedness. */
@@ -4136,18 +4135,8 @@ expand_call (tree exp, rtx target, int i
funtype, 1);
gcc_assert (GET_MODE (target) == pmode);
- if ((WORDS_BIG_ENDIAN || BYTES_BIG_ENDIAN)
- && (GET_MODE_SIZE (GET_MODE (target))
- > GET_MODE_SIZE (TYPE_MODE (type))))
- {
- offset = GET_MODE_SIZE (GET_MODE (target))
- - GET_MODE_SIZE (TYPE_MODE (type));
- if (! BYTES_BIG_ENDIAN)
- offset = (offset / UNITS_PER_WORD) * UNITS_PER_WORD;
- else if (! WORDS_BIG_ENDIAN)
- offset %= UNITS_PER_WORD;
- }
-
+ unsigned int offset = subreg_lowpart_offset (TYPE_MODE (type),
+ GET_MODE (target));
target = gen_rtx_SUBREG (TYPE_MODE (type), target, offset);
SUBREG_PROMOTED_VAR_P (target) = 1;
SUBREG_PROMOTED_SET (target, unsignedp);
Index: gcc/cse.c
===================================================================
--- gcc/cse.c 2017-08-22 17:14:30.334912144 +0100
+++ gcc/cse.c 2017-08-23 10:46:06.552151584 +0100
@@ -5964,7 +5964,6 @@ cse_insn (rtx_insn *insn)
rtx new_src = 0;
unsigned src_hash;
struct table_elt *src_elt;
- int byte = 0;
/* Ignore invalid entries. */
if (!REG_P (elt->exp)
@@ -5977,13 +5976,8 @@ cse_insn (rtx_insn *insn)
new_src = elt->exp;
else
{
- /* Calculate big endian correction for the SUBREG_BYTE.
- We have already checked that M1 (GET_MODE (dest))
- is not narrower than M2 (new_mode). */
- if (BYTES_BIG_ENDIAN)
- byte = (GET_MODE_SIZE (GET_MODE (dest))
- - GET_MODE_SIZE (new_mode));
-
+ unsigned int byte
+ = subreg_lowpart_offset (new_mode, GET_MODE (dest));
new_src = simplify_gen_subreg (new_mode, elt->exp,
GET_MODE (dest), byte);
}
Index: gcc/regcprop.c
===================================================================
--- gcc/regcprop.c 2017-08-21 15:49:31.652164829 +0100
+++ gcc/regcprop.c 2017-08-23 10:46:06.553156355 +0100
@@ -344,8 +344,7 @@ copy_value (rtx dest, rtx src, struct va
We can't properly represent the latter case in our tables, so don't
record anything then. */
else if (sn < (unsigned int) hard_regno_nregs[sr][vd->e[sr].mode]
- && (GET_MODE_SIZE (vd->e[sr].mode) > UNITS_PER_WORD
- ? WORDS_BIG_ENDIAN : BYTES_BIG_ENDIAN))
+ && subreg_lowpart_offset (GET_MODE (dest), vd->e[sr].mode) != 0)
return;
/* If SRC had been assigned a mode narrower than the copy, we can't
@@ -878,8 +877,7 @@ copyprop_hardreg_forward_1 (basic_block
is also invalid. */
if (hard_regno_nregs[regno][mode]
< hard_regno_nregs[regno][vd->e[regno].mode]
- && (GET_MODE_SIZE (vd->e[regno].mode) > UNITS_PER_WORD
- ? WORDS_BIG_ENDIAN : BYTES_BIG_ENDIAN))
+ && subreg_lowpart_offset (mode, vd->e[regno].mode) != 0)
goto no_move_special_case;
}
