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.sandif...@linaro.org>
Alan Hayward <alan.hayw...@arm.com>
David Sherwood <david.sherw...@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.
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. */
