On 19-06-14 18:43, Richard Henderson wrote:
On 06/19/2014 09:37 AM, Tom de Vries wrote:
On 19-06-14 05:59, Richard Henderson wrote:
On 06/01/2014 04:27 AM, Tom de Vries wrote:
+ if (TARGET_AAPCS_BASED)
+ {
+ /* For AAPCS, IP and CC can be clobbered by veneers inserted by the
+ linker. We need to add these to allow
+ arm_call_fusage_contains_non_callee_clobbers to return true. */
+ rtx *fusage = &CALL_INSN_FUNCTION_USAGE (insn);
+ clobber_reg (fusage, gen_rtx_REG (word_mode, IP_REGNUM));
+ clobber_reg (fusage, gen_rtx_REG (word_mode, CC_REGNUM));
Why are you adding CC_REGNUM if fixed registers are automatically included?
Richard,
You're right, setting a fixed register here is not required for
fuse-caller-save to work safely.
But it fits the definition of the hook
TARGET_CALL_FUSAGE_CONTAINS_NON_CALLEE_CLOBBERS:
...
Set to true if all the calls in the current function contain clobbers in
CALL_INSN_FUNCTION_USAGE for the registers that are clobbered by the call
rather than by the callee, and are not already set or clobbered in the call
pattern.
...
We can adapt the definition to not include fixed registers. I can make a patch
for that, if you like.
I think that would be best. It'll save just a bit of memory and scanning time.
Richard,
Now that the definition is updated not to include fixed registers, I've removed
the superfluous clobber of cc.
Build and reg-tested on arm, and committed.
Thanks,
- Tom
2014-06-25 Tom de Vries <t...@codesourcery.com>
* config/arm/arm.c (arm_emit_call_insn): Remove clobber of CC_REGNUM.
diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index 464dec1..0146fe8 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -17642,11 +17642,11 @@ arm_emit_call_insn (rtx pat, rtx addr, bool sibcall)
if (TARGET_AAPCS_BASED)
{
/* For AAPCS, IP and CC can be clobbered by veneers inserted by the
- linker. We need to add these to allow setting
- TARGET_CALL_FUSAGE_CONTAINS_NON_CALLEE_CLOBBERS to true. */
+ linker. We need to add an IP clobber to allow setting
+ TARGET_CALL_FUSAGE_CONTAINS_NON_CALLEE_CLOBBERS to true. A CC clobber
+ is not needed since it's a fixed register. */
rtx *fusage = &CALL_INSN_FUNCTION_USAGE (insn);
clobber_reg (fusage, gen_rtx_REG (word_mode, IP_REGNUM));
- clobber_reg (fusage, gen_rtx_REG (word_mode, CC_REGNUM));
}
}
--
1.9.1
