Recent commit introduced a conditional branch in eh_return epilogues
that is not compatible with speculation tracking:
commit 426fddcbdad6746fe70e031f707fb07f55dfb405
Author: Szabolcs Nagy <szabolcs.n...@arm.com>
CommitDate: 2023-11-27 15:52:48 +0000
aarch64: Use br instead of ret for eh_return
gcc/ChangeLog:
PR target/112987
* config/aarch64/aarch64.cc (aarch64_expand_epilogue): Use
explicit compare and separate jump with speculation tracking.
---
gcc/config/aarch64/aarch64.cc | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/gcc/config/aarch64/aarch64.cc b/gcc/config/aarch64/aarch64.cc
index e6bd3fd0bb4..e6de62dc02a 100644
--- a/gcc/config/aarch64/aarch64.cc
+++ b/gcc/config/aarch64/aarch64.cc
@@ -9879,7 +9879,17 @@ aarch64_expand_epilogue (rtx_call_insn *sibcall)
is just as correct as retaining the CFA from the body
of the function. Therefore, do nothing special. */
rtx label = gen_label_rtx ();
- rtx x = gen_rtx_EQ (VOIDmode, EH_RETURN_TAKEN_RTX, const0_rtx);
+ rtx x;
+ if (aarch64_track_speculation)
+ {
+ /* Emit an explicit compare, so cc can be tracked. */
+ rtx cc_reg = aarch64_gen_compare_reg (EQ,
+ EH_RETURN_TAKEN_RTX,
+ const0_rtx);
+ x = gen_rtx_EQ (GET_MODE (cc_reg), cc_reg, const0_rtx);
+ }
+ else
+ x = gen_rtx_EQ (VOIDmode, EH_RETURN_TAKEN_RTX, const0_rtx);
x = gen_rtx_IF_THEN_ELSE (VOIDmode, x,
gen_rtx_LABEL_REF (Pmode, label), pc_rtx);
rtx jump = emit_jump_insn (gen_rtx_SET (pc_rtx, x));
--
2.25.1
