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RE: [PATCH GCC/ARM]Fix rtx cost for Thumb1
- From: "Bin Cheng" <bin dot cheng at arm dot com>
- To: "Richard Earnshaw" <Richard dot Earnshaw at arm dot com>
- Cc: <gcc-patches at gcc dot gnu dot org>
- Date: Wed, 27 Mar 2013 16:22:45 +0800
- Subject: RE: [PATCH GCC/ARM]Fix rtx cost for Thumb1
- References: <002601ce29fc$afd803b0$0f880b10$ at cheng@arm.com> <51517F0D dot 30008 at arm dot com>
> -----Original Message-----
> From: Richard Earnshaw
> Sent: Tuesday, March 26, 2013 6:57 PM
> To: Bin Cheng
> Cc: gcc-patches@gcc.gnu.org
> Subject: Re: [PATCH GCC/ARM]Fix rtx cost for Thumb1
>
> On 26/03/13 08:34, Bin Cheng wrote:
> > Hi,
> > As reported in PR56102, arm back end returns wrong rtx cost for
> > pattern SET/ASHIFT/ASHIFTRT/LSHIFTRT/ROTATERT with multi-word mode.
> > This causes GCC skipping the split process in lower-subreg.c, and
> > generating bigger constant pool.
> >
> > This patch fixes the issue. Tested on arm-none-eabi/thumb1/O2/Os, ok
> > for trunk?
> >
> > Thanks.
> >
> > 2013-03-26 Bin Cheng <bin.cheng@arm.com>
> >
> > PR target/56102
> > * config/arm/arm.c (thumb1_rtx_costs, thumb1_size_rtx_costs): Fix
> > rtx costs for SET/ASHIFT/ASHIFTRT/LSHIFTRT/ROTATERT patterns with
> > mult-word mode.
> >
>
Sorry that I mis-sent the old version patch. The right one is attached now.
Since the difference is obvious and was approved before this thread, I
committed it directly as revision 197155.
Thanks.
Index: gcc/ChangeLog
===================================================================
--- gcc/ChangeLog (revision 197154)
+++ gcc/ChangeLog (working copy)
@@ -1,3 +1,10 @@
+2013-03-27 Bin Cheng <bin.cheng@arm.com>
+
+ PR target/56102
+ * config/arm/arm.c (thumb1_rtx_costs, thumb1_size_rtx_costs): Fix
+ rtx costs for SET/ASHIFT/ASHIFTRT/LSHIFTRT/ROTATERT patterns with
+ mult-word mode.
+
2013-03-27 Andreas Krebbel <Andreas.Krebbel@de.ibm.com>
* config/s390/s390.h (TARGET_FLT_EVAL_METHOD): Define.
Index: gcc/config/arm/arm.c
===================================================================
--- gcc/config/arm/arm.c (revision 197154)
+++ gcc/config/arm/arm.c (working copy)
@@ -7116,7 +7116,7 @@ static inline int
thumb1_rtx_costs (rtx x, enum rtx_code code, enum rtx_code outer)
{
enum machine_mode mode = GET_MODE (x);
- int total;
+ int total, words;
switch (code)
{
@@ -7124,6 +7124,8 @@ thumb1_rtx_costs (rtx x, enum rtx_code code, enum
case ASHIFTRT:
case LSHIFTRT:
case ROTATERT:
+ return (mode == SImode) ? COSTS_N_INSNS (1) : COSTS_N_INSNS (2);
+
case PLUS:
case MINUS:
case COMPARE:
@@ -7147,7 +7149,10 @@ thumb1_rtx_costs (rtx x, enum rtx_code code, enum
return COSTS_N_INSNS (1) + 16;
case SET:
- return (COSTS_N_INSNS (1)
+ /* A SET doesn't have a mode, so let's look at the SET_DEST to get
+ the mode. */
+ words = ARM_NUM_INTS (GET_MODE_SIZE (GET_MODE (SET_DEST (x))));
+ return (COSTS_N_INSNS (words)
+ 4 * ((MEM_P (SET_SRC (x)))
+ MEM_P (SET_DEST (x))));
@@ -7844,6 +7849,7 @@ static inline int
thumb1_size_rtx_costs (rtx x, enum rtx_code code, enum rtx_code outer)
{
enum machine_mode mode = GET_MODE (x);
+ int words;
switch (code)
{
@@ -7851,6 +7857,8 @@ thumb1_size_rtx_costs (rtx x, enum rtx_code code,
case ASHIFTRT:
case LSHIFTRT:
case ROTATERT:
+ return (mode == SImode) ? COSTS_N_INSNS (1) : COSTS_N_INSNS (2);
+
case PLUS:
case MINUS:
case COMPARE:
@@ -7869,7 +7877,10 @@ thumb1_size_rtx_costs (rtx x, enum rtx_code code,
return COSTS_N_INSNS (1);
case SET:
- return (COSTS_N_INSNS (1)
+ /* A SET doesn't have a mode, so let's look at the SET_DEST to get
+ the mode. */
+ words = ARM_NUM_INTS (GET_MODE_SIZE (GET_MODE (SET_DEST (x))));
+ return (COSTS_N_INSNS (words)
+ 4 * ((MEM_P (SET_SRC (x)))
+ MEM_P (SET_DEST (x))));