diff mbox series

rs6000: Don't use r12 for CR save on ELFv2 (PR102107)

Message ID 2484f7a4b0f52e6ed04754be336f1fa6fde47f6b.1630703147.git.segher@kernel.crashing.org
State New
Headers show
Series rs6000: Don't use r12 for CR save on ELFv2 (PR102107) | expand

Commit Message

Segher Boessenkool Sept. 3, 2021, 9:06 p.m. UTC 
CR is saved and/or restored on some paths where GPR12 is already live
since it has a meaning in the calling convention in the ELFv2 ABI.

It is not completely clear to me that we can always use r11 here, but
it does seem save, there is checking code (to detect conflicts here),
and it is stage 1.  So here goes.


Segher


2021-09-03  Segher Boessenkool <segher@kernel.crashing.org>

	PR target/102107
	* config/rs6000/rs6000-logue.c (rs6000_emit_prologue): On ELFv2 use r11
	instead of r12 for CR save, in all cases.
---
 gcc/config/rs6000/rs6000-logue.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)
diff mbox series

Patch

diff --git a/gcc/config/rs6000/rs6000-logue.c b/gcc/config/rs6000/rs6000-logue.c
index 07337c4836a3..e363d56ecec0 100644
--- a/gcc/config/rs6000/rs6000-logue.c
+++ b/gcc/config/rs6000/rs6000-logue.c
@@ -3293,10 +3293,13 @@  rs6000_emit_prologue (void)
 
   /* If we need to save CR, put it into r12 or r11.  Choose r12 except when
      r12 will be needed by out-of-line gpr save.  */
-  cr_save_regno = ((DEFAULT_ABI == ABI_AIX || DEFAULT_ABI == ABI_ELFv2)
-		   && !(strategy & (SAVE_INLINE_GPRS
-				    | SAVE_NOINLINE_GPRS_SAVES_LR))
-		   ? 11 : 12);
+  if (DEFAULT_ABI == ABI_AIX
+      && !(strategy & (SAVE_INLINE_GPRS | SAVE_NOINLINE_GPRS_SAVES_LR)))
+    cr_save_regno = 11;
+  else if (DEFAULT_ABI == ABI_ELFv2)
+    cr_save_regno = 11;
+  else
+    cr_save_regno = 12;
   if (!WORLD_SAVE_P (info)
       && info->cr_save_p
       && REGNO (frame_reg_rtx) != cr_save_regno