https://gcc.gnu.org/g:3cf0e6ab2aa9e7cb9a406079ff19856a6461d9f0
commit r15-6833-g3cf0e6ab2aa9e7cb9a406079ff19856a6461d9f0
Author: Maciej W. Rozycki <ma...@orcam.me.uk>
Date: Sun Jan 12 16:48:53 2025 +0000
Alpha: Restore frame pointer last in `builtin_longjmp' [PR64242]
Add similar arrangements to `builtin_longjmp' for Alpha as with commit
71b144289c1c ("re PR middle-end/64242 (Longjmp expansion incorrect)")
and commit 511ed59d0b04 ("Fix PR64242 - Longjmp expansion incorrect"),
so as to restore the frame pointer last, so that accesses to a local
buffer supplied can still be fulfilled with memory accesses via the
original frame pointer, fixing:
FAIL: gcc.c-torture/execute/pr64242.c -O0 execution test
FAIL: gcc.c-torture/execute/pr64242.c -O1 execution test
FAIL: gcc.c-torture/execute/pr64242.c -O2 execution test
FAIL: gcc.c-torture/execute/pr64242.c -O3 -g execution test
FAIL: gcc.c-torture/execute/pr64242.c -Os execution test
FAIL: gcc.c-torture/execute/pr64242.c -O2 -flto -fno-use-linker-plugin
-flto-partition=none execution test
FAIL: gcc.c-torture/execute/pr64242.c -O2 -flto -fuse-linker-plugin
-fno-fat-lto-objects execution test
and adding no regressions in `alpha-linux-gnu' testing.
gcc/
PR middle-end/64242
* config/alpha/alpha.md (`builtin_longjmp'): Restore frame
pointer last. Add frame clobber and schedule blockage.
Diff:
---
gcc/config/alpha/alpha.md | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/gcc/config/alpha/alpha.md b/gcc/config/alpha/alpha.md
index 35c8030422f5..178ce992206d 100644
--- a/gcc/config/alpha/alpha.md
+++ b/gcc/config/alpha/alpha.md
@@ -5005,14 +5005,28 @@
rtx pv = gen_rtx_REG (Pmode, 27);
/* This bit is the same as expand_builtin_longjmp. */
+
emit_clobber (gen_rtx_MEM (BLKmode, gen_rtx_SCRATCH (VOIDmode)));
emit_clobber (gen_rtx_MEM (BLKmode, hard_frame_pointer_rtx));
- emit_move_insn (hard_frame_pointer_rtx, fp);
+
emit_move_insn (pv, lab);
+
+ /* Restore the frame pointer and stack pointer. We must use a
+ temporary since the setjmp buffer may be a local. */
+ fp = copy_to_reg (fp);
emit_stack_restore (SAVE_NONLOCAL, stack);
+
+ /* Ensure the frame pointer move is not optimized. */
+ emit_insn (gen_blockage ());
+ emit_clobber (hard_frame_pointer_rtx);
+ emit_clobber (frame_pointer_rtx);
+ emit_move_insn (hard_frame_pointer_rtx, fp);
+
emit_use (hard_frame_pointer_rtx);
emit_use (stack_pointer_rtx);
+ /* End of the bit corresponding to expand_builtin_longjmp. */
+
/* Load the label we are jumping through into $27 so that we know
where to look for it when we get back to setjmp's function for
restoring the gp. */
