Testing on h8300, newlib/libm/math/ef_j0.c revealed a crash.
The problem is that PREV turned out to be unlinked when we came to
fixup_args_size_notes (prev, PREV_INSN (next),
INTVAL (XEXP (p, 0)));
I'm not sure how this didn't previously crash at
fixup_eh_region_note (insn, prev, next);
Thanks to reload inheritance deleting insns out from under, I can't
think of any other mechanism than to have a marker note before INSN
that won't get deleted.
Comments?
r~
commit 90060c3e9508d3bd0c930ba13cbe3230c7ea0b8f
Author: Richard Henderson <[email protected]>
Date: Mon Aug 1 18:47:04 2011 -0700
reload: Work around reload inheritence deleting insns.
diff --git a/gcc/reload1.c b/gcc/reload1.c
index 3233580..ba6ce37 100644
--- a/gcc/reload1.c
+++ b/gcc/reload1.c
@@ -4548,7 +4548,7 @@ reload_as_needed (int live_known)
#if defined (AUTO_INC_DEC)
int i;
#endif
- rtx x;
+ rtx x, marker;
memset (spill_reg_rtx, 0, sizeof spill_reg_rtx);
memset (spill_reg_store, 0, sizeof spill_reg_store);
@@ -4559,6 +4559,10 @@ reload_as_needed (int live_known)
set_initial_elim_offsets ();
+ /* Generate a marker insn that we will move around. */
+ marker = emit_note (NOTE_INSN_DELETED);
+ unlink_insn_chain (marker, marker);
+
for (chain = reload_insn_chain; chain; chain = chain->next)
{
rtx prev = 0;
@@ -4631,7 +4635,10 @@ reload_as_needed (int live_known)
rtx next = NEXT_INSN (insn);
rtx p;
+ /* ??? PREV can get deleted by reload inheritance.
+ Work around this by emitting a marker note. */
prev = PREV_INSN (insn);
+ reorder_insns_nobb (marker, marker, prev);
/* Now compute which reload regs to reload them into. Perhaps
reusing reload regs from previous insns, or else output
@@ -4649,6 +4656,9 @@ reload_as_needed (int live_known)
and that we moved the structure into). */
subst_reloads (insn);
+ prev = PREV_INSN (marker);
+ unlink_insn_chain (marker, marker);
+
/* Adjust the exception region notes for loads and stores. */
if (cfun->can_throw_non_call_exceptions && !CALL_P (insn))
fixup_eh_region_note (insn, prev, next);
