diff mbox

Make more use of subreg_size_lowpart_offset

Message ID 87wp5utv2h.fsf@linaro.org
State Accepted
Commit e10326ff910ab337741d0781a536435d51c5f044
Headers show

Commit Message

Richard Sandiford Aug. 23, 2017, 10:52 a.m. UTC 
This patch uses subreg_size_lowpart_offset in places that open-coded
the calculation.  The reload use (and the LRA one that was based on it)
seemed to ignore the BYTES_BIG_ENDIAN != WORDS_BIG_ENDIAN case; it's not
obvious whether that was deliberate or an oversight.

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.sandiford@linaro.org>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

gcc/
	* lra-spills.c (assign_mem_slot): Use subreg_size_lowpart_offset.
	* regcprop.c (maybe_mode_change): Likewise.
	* reload1.c (alter_reg): Likewise.

Comments

Jeff Law Oct. 12, 2017, 6:14 p.m. UTC | #1 
On 08/23/2017 04:52 AM, Richard Sandiford wrote:
> This patch uses subreg_size_lowpart_offset in places that open-coded

> the calculation.  The reload use (and the LRA one that was based on it)

> seemed to ignore the BYTES_BIG_ENDIAN != WORDS_BIG_ENDIAN case; it's not

> obvious whether that was deliberate or an oversight.

> 

> 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.sandiford@linaro.org>

> 	    Alan Hayward  <alan.hayward@arm.com>

> 	    David Sherwood  <david.sherwood@arm.com>

> 

> gcc/

> 	* lra-spills.c (assign_mem_slot): Use subreg_size_lowpart_offset.

> 	* regcprop.c (maybe_mode_change): Likewise.

> 	* reload1.c (alter_reg): Likewise.

I'm pretty sure the lra/reload case is just an oversight.  It's just
trying to get an adjustment so that it can make a MEM that covers the slot.

It's not absolutely clear to me that the regcprop bits are just an
open-coded subreg_size_lowpart_offset.  But I'll willing to trust you on
that one.

jeff
diff mbox

Patch

Index: gcc/lra-spills.c
===================================================================
--- gcc/lra-spills.c	2017-05-18 07:51:05.680420976 +0100
+++ gcc/lra-spills.c	2017-08-23 10:46:45.029672093 +0100
@@ -153,9 +153,7 @@  assign_mem_slot (int i)
 
   /* On a big endian machine, the "address" of the slot is the address
      of the low part that fits its inherent mode.  */
-  if (BYTES_BIG_ENDIAN && inherent_size < total_size)
-    adjust += (total_size - inherent_size);
-
+  adjust += subreg_size_lowpart_offset (inherent_size, total_size);
   x = adjust_address_nv (x, GET_MODE (regno_reg_rtx[i]), adjust);
 
   /* Set all of the memory attributes as appropriate for a spill.  */
Index: gcc/regcprop.c
===================================================================
--- gcc/regcprop.c	2017-08-23 10:46:06.553156355 +0100
+++ gcc/regcprop.c	2017-08-23 10:46:45.029672093 +0100
@@ -410,13 +410,9 @@  maybe_mode_change (machine_mode orig_mod
       int use_nregs = hard_regno_nregs[copy_regno][new_mode];
       int copy_offset
 	= GET_MODE_SIZE (copy_mode) / copy_nregs * (copy_nregs - use_nregs);
-      int offset
-	= GET_MODE_SIZE (orig_mode) - GET_MODE_SIZE (new_mode) - copy_offset;
-      int byteoffset = offset % UNITS_PER_WORD;
-      int wordoffset = offset - byteoffset;
-
-      offset = ((WORDS_BIG_ENDIAN ? wordoffset : 0)
-		+ (BYTES_BIG_ENDIAN ? byteoffset : 0));
+      unsigned int offset
+	= subreg_size_lowpart_offset (GET_MODE_SIZE (new_mode) + copy_offset,
+				      GET_MODE_SIZE (orig_mode));
       regno += subreg_regno_offset (regno, orig_mode, offset, new_mode);
       if (HARD_REGNO_MODE_OK (regno, new_mode))
 	return gen_raw_REG (new_mode, regno);
Index: gcc/reload1.c
===================================================================
--- gcc/reload1.c	2017-08-22 17:14:30.339835581 +0100
+++ gcc/reload1.c	2017-08-23 10:46:45.030666964 +0100
@@ -2253,8 +2253,7 @@  alter_reg (int i, int from_reg, bool don
 
       /* On a big endian machine, the "address" of the slot
 	 is the address of the low part that fits its inherent mode.  */
-      if (BYTES_BIG_ENDIAN && inherent_size < total_size)
-	adjust += (total_size - inherent_size);
+      adjust += subreg_size_lowpart_offset (inherent_size, total_size);
 
       /* If we have any adjustment to make, or if the stack slot is the
 	 wrong mode, make a new stack slot.  */