Previously we allowed subregs of non-GPR modes to be base and index
registers in non-strict mode. In practice such subregs will always
require a reload, so we get better code by disallowing them.
Tested on aarch64-linux-gnu. OK to install?
Richard
2017-08-22 Richard Sandiford <richard.sandif...@linaro.org>
Alan Hayward <alan.hayw...@arm.com>
David Sherwood <david.sherw...@arm.com>
gcc/
* config/aarch64/aarch64.c (aarch64_base_register_rtx_p): Only allow
subregs whose inner modes can be stored in GPRs.
(aarch64_classify_index): Likewise.
Index: gcc/config/aarch64/aarch64.c
===================================================================
--- gcc/config/aarch64/aarch64.c 2017-08-22 10:12:29.280432708 +0100
+++ gcc/config/aarch64/aarch64.c 2017-08-22 10:13:53.032828125 +0100
@@ -4196,7 +4196,9 @@ aarch64_regno_ok_for_base_p (int regno,
static bool
aarch64_base_register_rtx_p (rtx x, bool strict_p)
{
- if (!strict_p && GET_CODE (x) == SUBREG)
+ if (!strict_p
+ && GET_CODE (x) == SUBREG
+ && contains_reg_of_mode[GENERAL_REGS][GET_MODE (SUBREG_REG (x))])
x = SUBREG_REG (x);
return (REG_P (x) && aarch64_regno_ok_for_base_p (REGNO (x), strict_p));
@@ -4343,7 +4345,9 @@ aarch64_classify_index (struct aarch64_a
else
return false;
- if (GET_CODE (index) == SUBREG)
+ if (!strict_p
+ && GET_CODE (index) == SUBREG
+ && contains_reg_of_mode[GENERAL_REGS][GET_MODE (SUBREG_REG (index))])
index = SUBREG_REG (index);
if ((shift == 0 ||
