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Re: [PATCH] ARM: exclude fixed_regs for stack-alignment save/restore
Here's the version of the change that incorporates Mike's suggestion.
Thanks,
Roland
gcc/
2012-06-14 Roland McGrath <mcgrathr@google.com>
* config/arm/arm.c (arm_get_frame_offsets): Never use a fixed register
as the extra register to save/restore for stack-alignment padding.
diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index 092e202..13771d9 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -16752,7 +16752,12 @@ arm_get_frame_offsets (void)
else
for (i = 4; i <= (TARGET_THUMB1 ? LAST_LO_REGNUM : 11); i++)
{
- if ((offsets->saved_regs_mask & (1 << i)) == 0)
+ /* While the gratuitous register save/restore is ordinarily
+ harmless, if a register is marked as fixed or global it
+ may be entirely forbidden by the system ABI to touch it,
+ so we should avoid those registers. */
+ if (!fixed_regs[i] && !global_regs[i]
+ && (offsets->saved_regs_mask & (1 << i)) == 0)
{
reg = i;
break;