On 23/06/2020 13:10, Kyrylo Tkachov wrote:
-----Original Message-----
From: Andre Vieira (lists) <andre.simoesdiasvie...@arm.com>
Sent: 22 June 2020 09:52
To: gcc-patches@gcc.gnu.org
Cc: Kyrylo Tkachov <kyrylo.tkac...@arm.com>
Subject: [PATCH][GCC][Arm] PR target/95646: Do not clobber callee saved
registers with CMSE
Hi,
As reported in bugzilla when the -mcmse option is used while compiling
for size (-Os) with a thumb-1 target the generated code will clear the
registers r7-r10. These however are callee saved and should be preserved
accross ABI boundaries. The reason this happens is because these
registers are made "fixed" when optimising for size with Thumb-1 in a
way to make sure they are not used, as pushing and popping hi-registers
requires extra moves to and from LO_REGS.
To fix this, this patch uses 'callee_saved_reg_p', which accounts for
this optimisation, instead of 'call_used_or_fixed_reg_p'. Be aware of
'callee_saved_reg_p''s definition, as it does still take call used
registers into account, which aren't callee_saved in my opinion, so it
is a rather misnoemer, works in our advantage here though as it does
exactly what we need.
Regression tested on arm-none-eabi.
Is this OK for trunk? (Will eventually backport to previous versions if
stable.)
Ok.
Thanks,
Kyrill
As I was getting ready to push this I noticed I didn't add any skip-ifs
to prevent this failing with specific target options. So here's a new
version with those.
Still OK?
Cheers,
Andre
Cheers,
Andre
gcc/ChangeLog:
2020-06-22 Andre Vieira <andre.simoesdiasvie...@arm.com>
PR target/95646
* config/arm/arm.c: (cmse_nonsecure_entry_clear_before_return):
Use 'callee_saved_reg_p' instead of
'calL_used_or_fixed_reg_p'.
gcc/testsuite/ChangeLog:
2020-06-22 Andre Vieira <andre.simoesdiasvie...@arm.com>
PR target/95646
* gcc.target/arm/pr95646.c: New test.
diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index
6b7ca829f1c8cbe3d427da474b079882dc522e1a..dac9a6fb5c41ce42cd7a278b417eab25239a043c
100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -26960,7 +26960,7 @@ cmse_nonsecure_entry_clear_before_return (void)
continue;
if (IN_RANGE (regno, IP_REGNUM, PC_REGNUM))
continue;
- if (call_used_or_fixed_reg_p (regno)
+ if (!callee_saved_reg_p (regno)
&& (!IN_RANGE (regno, FIRST_VFP_REGNUM, LAST_VFP_REGNUM)
|| TARGET_HARD_FLOAT))
bitmap_set_bit (to_clear_bitmap, regno);
diff --git a/gcc/testsuite/gcc.target/arm/pr95646.c
b/gcc/testsuite/gcc.target/arm/pr95646.c
new file mode 100644
index
0000000000000000000000000000000000000000..12d06a0c8c1ed7de1f8d4d15130432259e613a32
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/pr95646.c
@@ -0,0 +1,32 @@
+/* { dg-do compile } */
+/* { dg-skip-if "avoid conflicting multilib options" { *-*-* } { "-march=*" }
{ "-march=armv8-m.base" } } */
+/* { dg-skip-if "avoid conflicting multilib options" { *-*-* } { "-mcpu=*" } {
"-mcpu=cortex-m23" } } */
+/* { dg-skip-if "avoid conflicting multilib options" { *-*-* } { "-mfpu=*" } {
} } */
+/* { dg-skip-if "avoid conflicting multilib options" { *-*-* } {
"-mfloat-abi=*" } { "-mfloat-abi=soft" } } */
+/* { dg-options "-mcpu=cortex-m23 -mcmse" } */
+/* { dg-additional-options "-Os" } */
+/* { dg-final { check-function-bodies "**" "" } } */
+
+int __attribute__ ((cmse_nonsecure_entry))
+foo (void)
+{
+ return 1;
+}
+/* { { dg-final { scan-assembler-not "mov\tr9, r0" } } */
+
+/*
+** __acle_se_bar:
+** mov (r[0-3]), r9
+** push {\1}
+** ...
+** pop {(r[0-3])}
+** mov r9, \2
+** ...
+** bxns lr
+*/
+int __attribute__ ((cmse_nonsecure_entry))
+bar (void)
+{
+ asm ("": : : "r9");
+ return 1;
+}
