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 --git a/gcc/config/alpha/alpha.md b/gcc/config/alpha/alpha.md
index 35c8030422f5df39c85164925886eff02b4bb947..178ce992206dee1f64040adc850b6c7a30c14338 100644 (file)
--- 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.  */