https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88904
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |jakub at gcc dot gnu.org
--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
I think the right fix is something like:
--- gcc/cfgcleanup.c.jj 2019-01-01 12:37:19.147942300 +0100
+++ gcc/cfgcleanup.c 2019-01-21 16:35:00.737320489 +0100
@@ -338,6 +338,13 @@ thread_jump (edge e, basic_block b)
insn != NEXT_INSN (BB_END (b)) && !failed;
insn = NEXT_INSN (insn))
{
+ /* cond2 must not mention any register that is not equal to the
+ former block. Check this before processing that instruction,
+ as BB_END (b) could contain also clobbers. */
+ if (insn == BB_END (b)
+ && mentions_nonequal_regs (cond2, nonequal))
+ goto failed_exit;
+
if (INSN_P (insn))
{
rtx pat = PATTERN (insn);
@@ -362,11 +369,6 @@ thread_jump (edge e, basic_block b)
goto failed_exit;
}
- /* cond2 must not mention any register that is not equal to the
- former block. */
- if (mentions_nonequal_regs (cond2, nonequal))
- goto failed_exit;
-
EXECUTE_IF_SET_IN_REG_SET (nonequal, 0, i, rsi)
goto failed_exit;
i.e. verify the condition before processing the second conditional jump,
because it is evaluated with the state of registers before the instruction,
rather than after it.
