Hi Jeff,
this patch tries to fix the handling of pic_offset_rtx +
const(unspec(symbol_ref)+ const_int) in may_trap_p,
and restores the original state of affairs in update_equiv_regs.
What do you think is it OK to extract the symbol_ref out
of the unspec in this way, or is does it need a target hook?
Patch works at least for x86_64 and arm.
Is it OK for trunk?
Bernd.
2017-04-23 Bernd Edlinger <bernd.edlin...@hotmail.de>
rtl-optimizatoin/79286
* ira.c (update_equiv_regs): Revert to using may_tap_p again.
* rtlanal.c (rtx_addr_can_trap_p_1): SYMBOL_REF_FUNCTION_P can never
trap. Extract constant offset from pic_offset_table_rtx +
const(unspec(symbol_ref)+int_val) and pic_offset_table_rtx +
const(unspec(symbol_ref)), otherwise RTL may trap.
Index: gcc/ira.c
===================================================================
--- gcc/ira.c (revision 247077)
+++ gcc/ira.c (working copy)
@@ -3551,7 +3551,8 @@ update_equiv_regs (void)
if (DF_REG_DEF_COUNT (regno) == 1
&& note
&& !rtx_varies_p (XEXP (note, 0), 0)
- && def_dominates_uses (regno))
+ && (!may_trap_or_fault_p (XEXP (note, 0))
+ || def_dominates_uses (regno)))
{
rtx note_value = XEXP (note, 0);
remove_note (insn, note);
Index: gcc/rtlanal.c
===================================================================
--- gcc/rtlanal.c (revision 247077)
+++ gcc/rtlanal.c (working copy)
@@ -485,7 +485,7 @@ rtx_addr_can_trap_p_1 (const_rtx x, HOST_WIDE_INT
case SYMBOL_REF:
if (SYMBOL_REF_WEAK (x))
return 1;
- if (!CONSTANT_POOL_ADDRESS_P (x))
+ if (!CONSTANT_POOL_ADDRESS_P (x) && !SYMBOL_REF_FUNCTION_P (x))
{
tree decl;
HOST_WIDE_INT decl_size;
@@ -645,8 +645,23 @@ rtx_addr_can_trap_p_1 (const_rtx x, HOST_WIDE_INT
case PLUS:
/* An address is assumed not to trap if:
- it is the pic register plus a constant. */
- if (XEXP (x, 0) == pic_offset_table_rtx && CONSTANT_P (XEXP (x, 1)))
- return 0;
+ if (XEXP (x, 0) == pic_offset_table_rtx
+ && GET_CODE (XEXP (x, 1)) == CONST)
+ {
+ x = XEXP (XEXP (x, 1), 0);
+ if (GET_CODE (x) == UNSPEC
+ && GET_CODE (XVECEXP (x, 0, 0)) == SYMBOL_REF)
+ return rtx_addr_can_trap_p_1(XVECEXP (x, 0, 0),
+ offset, size, mode, unaligned_mems);
+ if (GET_CODE (x) == PLUS
+ && GET_CODE (XEXP (x, 0)) == UNSPEC
+ && GET_CODE (XVECEXP (XEXP (x, 0), 0, 0)) == SYMBOL_REF
+ && CONST_INT_P (XEXP (x, 1)))
+ return rtx_addr_can_trap_p_1(XVECEXP (XEXP (x, 0), 0, 0),
+ offset + INTVAL (XEXP (x, 1)),
+ size, mode, unaligned_mems);
+ return 1;
+ }
/* - or it is an address that can't trap plus a constant integer. */
if (CONST_INT_P (XEXP (x, 1))
